FIS-483 Engineering Study Report R1.03.11.19

Marathon Petroleum Company 

Catlettsburg Refinery, KY 

Capacity Improvement Study of LPCCR 

Platformer Heater (1-44-B-1/2/3/4) 

BY 

FURNACE IMPROVEMENTS 

1600 Highway 6, Suite 480 

Sugar Land, TX 77478 

www.heatflux.com 

(281) 980-0325 

FIS Project 483 March 2019 

1

Marathon Petroleum Company, Catlettsburg Refinery, KY 

Capacity Improvement Study of LPCCR Platformer Heater (1-44-B-1/2/3/4) 

Table of Contents 

Section 1 Executive Summary .......................................... 11 

1.1 Introduction ............................................................................................. 11 

1.2 Design Observations .............................................................................. 11 

1.3 Operating Observations ......................................................................... 12 

1.4 Recommendation .................................................................................... 12 

1.5 Cost Estimation ....................................................................................... 13 

Section 2 Scope of Services & Design Basis .................. 15 

2.1 Scope of Services ................................................................................... 15 

2.2 Design Basis ............................................................................................ 16 

2.3 Feed Data ................................................................................................. 18 

2.4 Fuel Gas Characteristics ........................................................................ 22 

Section 3 System Analysis ................................................ 23 

3.1 LPCCR Platformer Heater Description .................................................. 23 

3.2 Debutanizer Reboiler Description .......................................................... 38 

Section 4 Current Data Analysis ....................................... 44 

4.1 Analysis from Graphs ............................................................................. 44 

4.2 Current Operation Modeling ................................................................. 105 

Section 5 Recommendations .......................................... 139 

5.1 Split Flow Technology .......................................................................... 139 

Furnace Improvements 

Low Cost Solutions for Fired Heaters 2



5.2 Energy balance for process heat recovery in convection section ... 139 

5.3 New Convection Section with Split Flow Technology ....................... 140 

5.4 Proposed Convection Section Design ................................................ 141 

5.5 Proposed Design 3D Model .................................................................. 144 

5.6 Effect of Charge Rate on the proposed design with split flow 

convection section .......................................................................................... 158 

5.7 Salient Features of Revamp Model ...................................................... 161 

Section 6 Cost Estimation ............................................... 164 

6.1 Basis of Cost Estimation ...................................................................... 164 

6.2 Proposed Design: New Convection Section ....................................... 164 

Section 7 Appendix .......................................................... 167 

7.1 List of P & ID’s ....................................................................................... 167 





List of Figures 

Figure 1: Naphtha Charge Rate, MBPD ....................................................................... 46 

Figure 2: Naphtha API Gravity, °API ............................................................................. 46 

Figure 3: Naphtha Charge Rate, Mlb/hr ....................................................................... 47 

Figure 4: Recycle Gas Flow Rate, MMSCFD .............................................................. 47 

Figure 5: Recycle Gas Flow Rate, Mlb/hr .................................................................... 48 

Figure 6: Recycle Gas / Naphtha Flow Rate Ratio ..................................................... 48 

Figure 7: Total Feed Flow Rate to Each Cell ............................................................... 49 

Figure 8: Charge Heater Feed Inlet Temperature ...................................................... 52 

Figure 9: Charge Heater Feed Outlet Temperature .................................................. 52 

Figure 10: Charge Heater Temperature Rise .............................................................. 53 

Figure 11: Charge Rate × ∆T of Charge Heater ......................................................... 53 

Figure 12: Charge Heater Tube Metal Temperature .................................................. 54 

Figure 13: Flue Gas Temperature Leaving Charge Heater ....................................... 54 

Figure 14: Excess O2 at Charge Heater ....................................................................... 55 

Figure 15: Charge Heater Fuel Gas Flow Rate ........................................................... 55 

Figure 16: Charge Heater Fuel Gas Pressure ............................................................. 56 

Figure 17: Charge Heater Firing Rate (Provided by Client) ..................................... 56 

Figure 18: Charge Heater Firing Rate (from Fuel Flow Rate) ................................... 57 

Figure 19: Charge Heater Firing Rate Comparison .................................................... 57 

Figure 20: Charge Rate × ∆T Vs Firing Rate of Charge Heater ............................... 58 

Figure 21: Charge Heater Bridge Wall Temperature Vs Firing Rate (Provided by 

Client) ................................................................................................................................. 58 





Figure 22: Inter Heater 1 Feed Inlet Temperature ...................................................... 62 

Figure 23: Inter Heater 1 Feed Outlet Temperature ................................................... 62 

Figure 24: Inter Heater 1 Temperature Rise ................................................................ 63 

Figure 25: Charge Rate × ∆T of Inter Heater 1 ........................................................... 63 

Figure 26: Inter Heater 1 Tube Metal Temperature .................................................... 64 

Figure 27: Flue Gas Temperature Leaving Inter Heater 1 ........................................ 64 

Figure 28: Excess O2 at Inter Heater 1 Exit ................................................................. 65 

Figure 29: Inter Heater 1 Fuel Gas Flow Rate ............................................................ 65 

Figure 30: Inter Heater 1 Fuel Gas Pressure .............................................................. 66 

Figure 31: Inter Heater 1 Firing Rate (Provided by Client) ........................................ 66 

Figure 32: Inter Heater 1 Firing Rate (from Fuel Flow Rate) .................................... 67 

Figure 33: Inter Heater 1 Firing Rate Comparison ...................................................... 67 

Figure 34: Charge Rate × ∆T Vs Firing Rate of Inter Heater 1 ................................. 68 

Figure 35: Inter Heater 1 Bridge Wall Temperature Vs Firing Rate (Provided by 

Client .................................................................................................................................. 68 



















Client) ................................................................................................................................. 78 















Client) ................................................................................................................................. 88 

Figure 64: Steam Generation Coil Circulation (MGPM) ............................................. 92 

Figure 65: Steam generation Coil Circulation (Mlb/hr) ............................................... 92 

Figure 66: Flow Rate of Steam Generated .................................................................. 93 

Figure 67: Boiler Feed Water Flow Rate (GPM) ......................................................... 93 





Figure 68: BFW Coil Inlet Temperature ........................................................................ 94 

Figure 69: BFW Coil Outlet Temperature ..................................................................... 94 

Figure 70: BFW Coil Temperature Rise ....................................................................... 95 

Figure 71: Average Flue Gas Temperature Leaving Radiant Section ..................... 95 

Figure 72: Flue Gas Temperature Leaving Convection Section .............................. 96 

Figure 73: Flue Gas Temperature Approach ............................................................... 96 

Figure 74: Flue Gas ΔT Across Convection ................................................................ 97 

Figure 75: Total Firing Rate (Provided by Client) ........................................................ 98 

Figure 76: Total Firing Rate (from Fuel Flow Rate) .................................................... 98 

Figure 77: Total Firing Rate Comparison ..................................................................... 99 

Figure 78: Flue Gas Temperature at Convection Exit Vs Total Firing Rate ........... 99 

Figure 79: Draft at Convection Entry ........................................................................... 100 

Figure 80: Average Excess O2 at Radiant Exit .......................................................... 100 

Figure 81: Stack Damper Position ............................................................................... 101 

Figure 82: Fuel Gas Molecular Weight ....................................................................... 103 

Figure 83: Fuel Gas Net Heating Value ...................................................................... 103 

Figure 84: Fuel Gas Molecular Weight Vs Fuel Heating Value .............................. 104 

Figure 85: Bridgewall Temperature Comparison ...................................................... 161 

Figure 86: Firing Rate Comparison ............................................................................. 162 

Figure 87: Flue Gas Convection Exit Temperature .................................................. 163 

Figure 88 : Reboiler Duty .............................................................................................. 173 

Figure 89: Debutanizer Reboiler Charge Flowrate ................................................... 173 

Figure 90: Debutanizer Reboiler Inlet Temperature ................................................. 174 

Figure 91: Debutanizer Reboiler Outlet Temperature .............................................. 174 





Figure 92: Draft at Convection Exit ............................................................................. 175 

Figure 93 Excess O2 at Stack ...................................................................................... 175 

Figure 94: Debutanizer Stack Damper Opening Percentage .................................. 176 

Figure 95 : Reboiler Stack Temperature .................................................................... 176 

Figure 96 : Fuel Gas Flowrate ...................................................................................... 177 

Figure 97 : Fuel Gas Pressure ..................................................................................... 177 





List of Tables 

Table 1: Existing Design Rich Case Data .................................................................... 16 

Table 2: Proposed Design Basis / Projected Operating Case .................................. 17 

Table 3: Debutanizer Data for Proposed Case ........................................................... 17 

Table 4: LPCCR Feed Distillation .................................................................................. 18 

Table 5 : LPCCR Feed Composition: - Naphtha ......................................................... 18 

Table 6 : Recycle Gas Composition .............................................................................. 20 

Table 7: Fuel Gas Properties ......................................................................................... 22 

Table 8: LPCCR Rich Feed Design Case Simulation ................................................ 29 

Table 9: Existing Heater Energy Balance .................................................................... 37 

Table 10: Debutanizer Reboiler Design Case Simulation ......................................... 41 

Table 11: List of Graphs of Feed ................................................................................... 44 

Table 12 : Analysis of Feed Operating Data ................................................................ 45 

Table 13: List of Graphs of Charge Heater .................................................................. 50 

Table 14: Analysis of Operating Data of Charge Heater ........................................... 51 

Table 15: List of Graphs of No. 1 Inter Heater ............................................................ 60 

Table 16: Analysis of Operating Data of No. 1 Inter Heater ...................................... 61 


Table 18: Analysis of Operating Data of No. 2 Inter Heater ...................................... 71 


Table 20: Analysis of Operating Data of No.3 Inter Heater ....................................... 81 

Table 21: List of Graphs of Convection Section .......................................................... 90 

Table 22: Analysis of Operating Data of Convection Section ................................... 91 





Table 23 : List of Graphs of Fuel ................................................................................. 102 

Table 24: Analysis of Operating Data of Fuel ............................................................ 102 

Table 25: Simulation of DCS Case (06/25/18) .......................................................... 106 

Table 26: Simulation of Maximum Firing Case (06/11/18) ...................................... 114 

Table 27: Simulation of Maximum Charge Case (08/30/18) ................................... 122 

Table 28: Simulation of Average Charge Case (04/13/18) ...................................... 130 

Table 29 : Proposed Convection Section Energy Balance ...................................... 140 

Table 30: Proposed Simulation Comparison ............................................................ 145 

Table 31 : List of Graphs of Debutanizer Reboiler .................................................... 171 

Table 32: Analysis of Operating Data of Debutanizer Reboiler ............................. 172 





1.1 Introduction 

Section 1 

Executive Summary 

FIS was employed by Marathon Catlettsburg Refinery, KY to carry out a capacity 

improvement study of LPCCR Platformer Heater (1-44-B-1/2/3/4). The existing 

Platformer Heater was built in 1992. It is designed for a Naphtha charge rate of 18.2 

MBPD and recycle gas rate of 26.4 MMSCFD. It is rated for 106.3 MMBtu/hr process 

absorbed duty in radiant section. The convection section recovers waste heat of 

50.5 MMBtu/hr and generates 55,966 lb/hr of steam. 

Marathon is operating the heater at an average of 22.9 MBPD of Naphtha charge 

rate. They are fuel gas pressure limited at burners for the Platformer heater. The 

charge heater inlet temperature is running 100 F lower than design. The outlet 

temperature is also 100 F lower, and this is limiting high octane conversion. 

The revamp will increase the outlet temperature by another 80 F, thus providing 

high outlet temperature to get the required octane conversion. Similar increase in 

outlet temperature is possible in the other cells. 

Marathon is looking to revamp the heater for a Naphtha feed rate 24.5 MBPD at 

higher octane, -which is maximum operated charge rate as per last one-year 

operating data and 40 MMSCFD of Recycle Gas flowrate. They want to increase the 

absorbed heat duty to 250 MMBtu/hr utilizing the maximum sustainable firing 

capacity of 280 MMBtu/hr (LHV). 

FIS has performed a Capacity Improvement Study to evaluate the complete 

performance. FIS analyzed the existing design and current operation of the heater. 

Based on the above, FIS has developed a very economical option for increasing the 

capacity of the Platformer Heater using our patented Split Flow Technology. With 

the split flow arrangement, the proposed new convection section can provide 44.25 

MMBtu/hr of absorbed process duty. The scheme also recovers 5.12 MMBtu/hr of 

debutanizer absorbed reboiler duty and generates 53,061 lb/hr of steam. 

1.2 Design Observations 

FIS has reviewed the existing design configuration of the Platformer heater. We ran 

the existing heater design simulation and the design is found to be in order. The 

simulation results closely match the process conditions, bridge wall temperature 

and steam generation in the datasheet. 





1.3 Operating Observations 

FIS has analyzed daily operating data of Platformer Heater for one year provided by 

Marathon. The following observations were made regarding the current operation of 

the heater: 

❖ Average feed flow rate to each cell is 263,190 lb/hr. 

❖ Average firing rate is 235.22 MMBtu/hr. 

❖ Feed inlet and outlet temperature in each cell are lower than the original design 

temperatures. Feed temperature rise in Charge Heater, inter heater 1 and Inter 

Heater 2 is higher than the design by 20°F. 

❖ Flue gas temperature leaving the convection section is around 571°F. 

❖ The excess O2 in the flue gas is in the range of 4.4%. 

❖ The burners are operated at higher fuel gas pressure in all the radiant cells than 

the original design. The average fuel gas pressure for No.1 Interheater, Charge 

heater, No.2 Interheater and No.3 Interheater are 22.2 psig, 25.1 psig, 22.4 psig 

and 28.5 psig respectively. 

❖ Firing rate (LHV) calculated from fuel pressure almost matches the firing rate 

provided by client 

❖ The calculated bridgewall temperature is higher than the actual. It could be that 

the radiant absorbed duty is higher than the calculated. Operating data 

simulation is indicating that the firing rates should be lower than the actual. It is 

also indicating that actual steam production is lower than calculated. We are not 

able to close the heat balance. This could be due to fuel gas flow measurement. 

1.4 Recommendation 

FIS recommends recovering process absorbed heat duty in convection section 

based on FIS Patented Split Flow Technology. We have optimized the required 

process absorbed duty as well as the design steam generation. 

In the proposed split flow arrangement, the process flow to the heater is split 

between radiant and convection sections. About 22.4-26.5% of the charge rate 

goes to the convection section split flow coil and the balance to the radiant coils. 

FIS proposes to run split flow piping from the inlet manifolds to the new convection 

coils and then return the convection section outlet split flow piping back to the 

outlet manifold from the radiant. We recommend installing a butterfly control valve 

to control the flow to the split flow convection coils so that the outlet temperature 

is maintained the same as the radiant section. 

The new convection section will be completely prefabricated in the shop. It 

consists 15 rows of tubes arranged in two modules. The bottom module consists 

of 7 rows of tubes and the top module consist of the rest 8 rows of tubes. 





The proposed convection houses process split flow coils for all four cells in the 

bottom module. The process coils consist of bare and finned tube rows. The 

steam generation coils are arranged above the process coils. The debutanizer 

reboiler coils are sandwiched between the steam generation coils. 

This revamped design of the heater with new convection section will increase the 

process absorbed heat duty from 106.3 MMBtu/hr to 191.7 MMBtu/hr. The total 

absorbed heat duty is 246.5 MMBtu/hr. Debutanizer absorbed heat duty is 5.12 

MMBtu/hr and Waste heat absorbed duty is 49.63 MMBtu/hr. 

The table below shows the comparison of existing design, maximum charge case 

and proposed design heat duties and the percentage flow through split flow coils: 

Heater 

Section 

No. 1 

Interheater 

Charge 

Heater 

No. 2 Inter 

Heater 

No. 3 Inter 

Heater 

Existing 

Design 

Case 

Maximum 

Charge case 

Proposed 

Design 

Case 

Extra Heat 

Duty 

Flow 

through 

split flow 

coils 

Heat Duty Absorbed, MMBtu/hr % 

37.46 42.97 66.13 23.16 26.46 

26.12 36.20 50.08 13.88 22.41 

28.70 35.56 49.20 13.64 22.93 

13.98 19.99 26.32 6.33 24.70 

Total Duty 106.3 134.7 191.7 57.0 

The process absorbed heat duty is being increased by almost 85.4 MMBtu/hr from 

the existing design heat duty and about 57 MMBtu/hr from the current operating 

levels of 134.7 MMBtu/hr. 

1.5 Cost Estimation 

FIS has developed ±30% cost estimates for Platformer Heater(1-44-B-1/2/3/4) 

revamp. The estimated cost for the proposed recommendation is $ 9.99 Million. 

The cost includes design engineering supply and erection of the new convection 

section. It also includes split flow piping and instrumentation. 





We hope you find our report helpful and informative. We will provide you all the help 

you need in implementing these changes. We will be happy to provide you with 

follow up support, should you need further information or clarifications. 





Section 2 

Scope of Services & Design Basis 

2.1 Scope of Services 

Following scope of services is considered for the Capacity Improvement Study 

of Platformer Heater: 

2.1.1 Review & Evaluation of Existing Platformer Heater 

❖ Review of existing design and drawings of the heater 

❖ Study of existing burner data sheets and drawings 

❖ Study of existing Process Flow Diagrams 

❖ Study of existing Piping & Instrumentation Diagram 

❖ Build a computer model of the existing heater 

❖ Carry out the thermal simulation of the existing heater: 

2.1.2 Current Operation Analysis 

❖ Obtain plant operating data from Marathon Catlettsburg Refinery for the 

past 3 years 

❖ Arrange, analyze & trend operating data 

❖ Select three sets of data corresponding to minimum, average and maximum 

operating conditions to identify the critical operating parameters for each 

data 

❖ Simulate the performance of the heater at these operating conditions 

❖ Check existing burner performance at current conditions 

❖ Remark and conclusion of the current condition of the heater 

2.1.3 Proposed Options 

❖ Evaluate Split Flow Technology and develop options to increase the 

heater capacity 

❖ Modeling the heater at projected operating conditions 

❖ Develop preliminary specifications of the modifications- radiant section, 

convection section, stack, piping 

❖ Identify modifications in the heater 

❖ Estimate ± 30% cost estimate of the proposed modification 

2.1.4 Exclusions 

Presently, our scope does not include the engineering / man hours for the 

following: 





❖ Detailed Design Engineering of proposed modifications 

❖ Any Mechanical / Structural / Civil design and calculations 

❖ Any Piping, Instrumentation and electrical design and calculations. 

❖ Any other activity not specifically mentioned in the scope of service 

2.2 Design Basis 

The following data from the heater datasheet is used for evaluating the existing 

design case of the Platformer heater: 

Parameters 

Process Absorbed 

Heat Duty 

Naphtha Charge 

Rate (Calculated) 

Recycle Gas Flow 

Rate (Calculated) 

Table 1: Existing Design Rich Case Data 

Unit 

Charge 

Heater 

Inter 

Heater 1 

Inter 

Heater 2 

Inter 

Heater 3 

MMBtu/hr 26.12 37.46 28.7 13.98 

MBPD 18.2 

MMSCFD 26.4 

Total Feed Flow Rate lb/hr 211,731 

Inlet Temperature °F 866 801 852 934 

Outlet Temperature °F 1,010 1,010 1,010 1,010 

Temperature Rise °F 144 209 158 76 

Inlet Pressure psig 77 71.8 68.2 63.0 

Outlet Pressure psig 75.8 69.8 66.2 61.3 

Coil Pressure Drop psi 1.2 2.0 2.0 1.7 

Waste Absorbed 

Heat Duty 

MMBtu/hr 50.5 

Firing Rate MMBtu/hr 177.51 





FIS considered 280 MMBtu/hr (LHV) as the maximum sustainable firing rate for the 

proposed design basis, based on the discussion with Marathon. The proposed 

design basis is as follows: 

Table 2: Proposed Design Basis / Projected Operating Case 

Parameters 

Process Absorbed 

Heat Duty 


Rate 

Recycle Gas Flow 

Rate 

Unit 

Charge 

Heater 

Inter 

Heater 1 

Inter 

Heater 2 

Inter 

Heater 3 

MMBtu/hr 53.4 60.5 48.6 29.5 

MBPD 24.5 

MMSCFD 40.0 

Total Feed Flow Rate lb/hr 288,160 

Inlet Temperature °F 741 728.7 795.9 847.1 

Outlet Temperature °F 953 988.7 990.0 954.0 

Temperature Rise °F 212 260 194.1 106.9 

Coil ΔP psi 1.2 2.0 2.0 1.7 

Debutanizer 

Absorbed Duty 

Waste Heat Absorbed 

Duty 

MMBtu/hr 5.0 

MMBtu/hr 53.0 

Firing Rate MMBtu/hr 280.0 

Table 3: Debutanizer Data for Proposed Case 

Parameters Unit Value 

Feed Flow Rate (75% of design feed 

flowrate) 

Feed inlet temperature (Outlet from 

Debutanizer) 

lb/hr 93,327 

°F 504 





2.3 Feed Data 

Table 4: LPCCR Feed Distillation 

Distillation % 

DCS Case 

06/25/18 

Max. 

Charge 

08/30/18 

Avg. 

Charge 

04/13/18 

Max. 

Firing 

06/11/18 

Avg. 

Firing 

03/17/18 

°F IBP 136 139 136 136 140 

°F 10% 157 189 156 158 188 

°F 20% 192 198 191 194 197 

°F 30% 203 209 200 206 208 

°F 40% 215 219 209 217 218 

°F 50% 230 240 221 231 231 

°F 60% 252 258 244 252 247 

°F 70% 272 280 261 270 260 

°F 80% 296 299 284 290 281 

°F 90% 335 339 319 324 308 

FBP 384 408 366 371 358 

Table 5 : LPCCR Feed Composition: - Naphtha 

Compositi 

on, % 

DCS Case 

06/25/18 

Max 

Charge 

08/30/18 

Average 

Charge 

04/13/18 

Maximum 

Firing 

06/11/18 

Average 

Firing 

03/17/18 

C6 P 6.03 4.30 8.04 6.15 7.02 

C7 P 8.60 8.42 7.95 8.63 9.05 

C8 P 6.54 6.40 5.86 6.92 6.92 





C9 P 4.44 4.14 4.08 4.61 4.25 

C10 P 2.38 2.63 2.26 2.39 1.98 

C11+ P 0.34 0.45 0.09 0.16 0.05 

C6 iso P 4.67 2.79 6.22 4.72 4.24 

C7 iso P 10.39 9.10 11.1 10.2 12.0 

C8 iso P 10.6 11.0 9.77 11.1 10.9 

C9 iso P 5.9 7.6 5.4 5.9 6.3 

C10 iso P 0.77 4.98 0.71 0.80 0.70 

C11+ iso P 0.84 1.21 0.01 0.84 0.01 

C6 A 0.72 0.47 0.98 0.74 0.78 

C8 A 3.20 2.65 3.38 3.32 3.28 

C9 A 0.52 2.42 0.15 0.51 0.13 

C10+ A 0.0 1.10 0.43 0.0 0.38 

C5 N 0.26 0.08 0.36 0.24 0.12 

C6 N 2.86 1.87 7.12 2.68 6.15 

C7 N 14.59 10.06 14.25 13.89 14.02 

C8 N 8.16 7.54 7.60 8.22 8.07 

C9 N 2.22 2.83 2.37 2.32 2.18 

C10+ N 0.0 1.17 0.01 0.01 0.00 

C6 O 0.54 0.32 0.72 0.53 0.45 

C7 O 3.75 2.42 0.0 3.54 0.0 





C8 O 0.16 0.22 0.17 0.18 0.18 

C9 O 0.54 1.22 0.56 0.57 0.51 

C10 O 0.0 0.96 0.01 0.00 0.00 

C7-C11 

Naptheno 

0.26 0.41 0.20 0.24 0.18 

C10 Indane 0.44 0.16 0.0 0.36 0.0 

Total 

Paraffins 

Total 

isoParaffins 

Total 

Aromatics 

Total 

Napthenes 

Total 

Olefins 

Total 

Unknowns 

Recycle 

Gas 

Information 

Rate, 

MMSCFD 

Molecular 

Weight 

28.49 26.44 28.33 28.95 29.31 

33.22 36.70 33.27 33.61 34.17 

4.89 6.91 4.98 4.93 4.61 

28.09 23.61 31.71 27.35 30.55 

5.26 5.61 1.67 5.08 1.33 

0.05 0.72 0.03 0.08 0.03 

Table 6 : Recycle Gas Composition 

DCS Case 

(06/25/18) 

Composition, mol% 

Max 

Charge 

(08/30/18) 

Avg Charge 

(04/13/18) 

Max Firing 

(06/11/18) 

Avg Firing 

(03/17/18) 

36.0 32.0 36.0 35.0 26.8 

5.41 

H2 85.3 90.2 77.2 85.3 81.5 

C1-C5 0.01 0.00 0.01 0.02 0.00 

2,2-DMC4 0.09 0.03 0.12 0.09 0.04 

CyC5 0.26 0.08 0.36 0.23 0.12 





2,3-DMC4 0.34 0.34 0.34 0.34 0.34 

2MC5 2.27 1.33 3.02 2.25 1.91 

3MC5 1.94 1.23 2.60 2.02 1.99 

nC6 6.03 4.30 8.04 6.15 7.02 

2,2-DMC5 0.19 0.20 0.18 0.17 0.20 

MCyC5 2.87 1.87 3.73 2.68 3.11 

Benzene 0.72 0.47 0.98 0.74 0.78 

CyC6 0.00 0.00 3.39 0.00 3.03 





2.4 Fuel Gas Characteristics 

The following fuel gas design composition from datasheet is used for the existing 

design, operating and proposed design simulations. 

Table 7: Fuel Gas Properties 

Parameters 

Units 

Refinery Gas 

Design 

Alternate 

Specific Gravity at 60°F - 0.68 0.60 

Heat of Combustion (LHV) Btu/Scf 1,120 1,005 

Fuel temperature at burner F 100 100 

Components 

H2 % 39.33 46.70 

CH4 % 18.41 22.60 

C2H6 % 24.34 14.10 

C3H6 % 1.21 2.30 

C3H8 % 12.58 7.80 

I-C4H10 % 1.31 2.00 

n-C4H10 % 1.61 2.00 

i-C5H12 % 1.21 1.25 

n-C5H12 % 0 1.25 

Total % 100 100 





Section 3 

System Analysis 

3.1 LPCCR Platformer Heater Description 

The CCR Platformer heater (1-44-B-1/2/3/4) is a four-cell box type with Vertical 

Arbor (“U”) coils. The Platformer heater has a common convection section and a 

self-supported & top mounted stack. The heater was originally built and installed in 

1992. The heater operates under natural draft. 

The Platformer heater radiant box 

consists of 4 cells; Charge heater, No. 1 

Interheater, No. 2 Interheater and No. 3 

Interheater. The radiant section of the 

heater is used to heat process service 

and the convection section is used for 

waste heat recovery. The total absorbed 

duty of the heater is 156.76 MMBtu/hr. 

The total process absorbed duty in the 

radiant section is 106.26 MMBtu/hr and 

the waste heat absorbed duty in the 

convection is 50.5 MMBtu/hr. 

The heater is designed for gas firing and 

is operated at 15% excess air. The firing 

rate of the heater is 177.51 MM Btu/hr 

(LHV). The net thermal efficiency of the 

heater is 88.3% (based on LHV) 

considering 2% radiation heat loss. 

3.1.1 Radiant Section 

The process feed to the radiant section is a mixture of Naphtha and Recycle Gas. 

The flue gas temperature leaving the radiant section is 1,500ºF. 

Charge Heater (1-44-B-1) 

The Charge heater is designed for a 26.12 MMBtu/hr absorbed heat duty. It has a 

normal absorbed duty of 23.75 MMBtu/hr. This cell is designed to heat 211,731 

lb/hr of feed from 866ºF to 1,010ºF. The feed enters at a pressure of 77 psig and 

leaves at 75.8 psig. The calculated coil pressure drop is 1.2 psi. The process fluid 

mass velocity is 23.8 lb/sec.ft 2 . The average radiant heat flux is 9,075 Btu/hr.ft 2 and 





the maximum radiant heat flux is 12,700 Btu/hr.ft 2 . The radiant tubes have a 

maximum metal temperature of 1,125°F. 

The Charge heater has 41.9 ft high, 38.14 ft long and 17.94 ft wide inside insulation 

dimensions. It consists of 28 inverted arbor coils arranged in 28 passes. The coils 

are 4” NPS x Sch 40. The coils are made of A335 Gr P9 material. The effective 

length of the coil is 87.3 ft. The coils are placed at a center to center spacing of 1.27 

ft. The radiant heat transfer area is 2,879 ft 2 . 

No.1 Interheater (1-44-B-2) 

The No.1 Interheater is designed for 37.46 MMBtu/hr absorbed duty. This cell is 

designed to heat 211,731 lb/hr of feed from 801ºF to 1,010ºF. The feed enters at a 

pressure of 71.8 psig and leaves at 69.8 psig. The calculated coil pressure drop is 

2 psi. The process fluid mass velocity is 23.8 lb/sec.ft 2 . The average radiant heat 

flux is 10,065 Btu/hr.ft 2 and the maximum radiant heat flux is 14,090 Btu/hr.ft 2 . The 

radiant tubes have a maximum metal temperature of 1,130°F. 

The No.1 Interheater has 54.47 ft high, 38.14 ft long and 15.05 ft wide inside 

insulation dimensions. It consists of 28 inverted arbor coils arranged in 28 passes. 

The coils are 4” NPS x Sch 40. The coils are made of A335 Gr P9 material. The 

effective length of the coil is 112.85 ft. The coils are placed at a center to center 

spacing of 1.27 ft. The radiant heat transfer area is 3,723 ft 2 . 




pressure of 68.2 psig and leaves at 66.2 psig. The calculated coil pressure drop is 

2 psi. The process fluid mass velocity is 23.8 lb/sec.ft 2 . The average radiant heat 



The No.2 Interheater has 41.9 ft high, 38.14 ft long and 16.1 ft wide inside insulation 








pressure of 63 psig and leaves at 61.3 psig. The calculated coil pressure drop is 





1.7 psi. The process fluid mass velocity is 23.8 lb/sec.ft 2 . The average radiant heat 



The No.3 Interheater has 26.2 ft high, 38.14 ft long and 14.9 ft wide inside insulation 





The tubes in all radiant cells are provided with inlet and outlet manifolds at the top. 

The radiant section manifolds are supported on spring hangers. All the manifolds 

are 24” NPS size, are made of A335 Gr P11 material. 

The radiant floor is lined with 8” thk. Kaolite 2200. Radiant section shielded walls 

are lined with 6” thk. Kaolite 2200. The exposed radiant walls below burner level 

are lined with 8” thk. Kaolite 2200 and above burner level are lined with 6” thk. 

Kaolite 2200. The radiant arch is lined with 6” thk. Kaolite 2200. 

Ducts Connecting Radiant and Convection Sections 

Flue gas from radiant section enters the convection section through 4 ducts. All the 

four radiant cells have an opening at the center. The offtake ducts are lined with 6” 

thk. Kaolite 2200 refractory. 

Burners 

The radiant section is fired with 30 natural draft fuel gas burners. The burners are 

John Zink Ultra Low NOx PNDR-18M/20M type and are installed at the end walls 

for horizontal firing. The burners are designed for fuel gas pressure of 20 psig and 

15% excess air. The burners are arranged for the single firing of the coils in all the 

cells. Each burner has a manually ignited pilot with a flame retention head. 

The Charge heater consists of 8 burners with 4 burners on each end wall. The 

burners have a design heat release of 7.81 MM Btu/hr. The normal heat release 

per burner is 6.25 MM Btu/hr. The turndown ratio of burners is 3:1. The draft loss 

across the burners varies from 0.32-0.45 in WC at design heat release and excess 

air at 70°F. The burners are spaced at a center to center distance of 4.5 ft. The 

distance between the burner centerline to tube centerline is 5.5 ft. 

The No.1 Inter heater consists of 10 burners with 5 burners on each end wall. The 


per burner is 6.25 MM Btu/hr. The turndown ratio of burners is 3:1. The draft at 

burners varies from 0.39-0.57 in WC at design heat release and excess air at 70°F. 





The burners are spaced at a center to center distance of 4.5 ft. The distance 

between the burner centerline to tube centerline is 6 ft. 



per burner is 6.25 MM Btu/hr. The turndown ratio of burners is 3:1. The draft at 

burners varies from 0.32-0.45 in WC at design heat release and excess air at 70°F. 

The burners are spaced at a center to center distance of 4.5 ft. The distance 

between the burner centerline to tube centerline is 5.5 ft. 


burners have a design heat release of 7 MM Btu/hr. The turndown ratio of burners 

is 3:1. The draft at burners varies from 0.26-0.30 in WC at design heat release and 

excess air at 70°F. The burners are spaced at a center to center distance of 4.5 ft. 

The distance between the burner centerline to tube centerline is 5 ft. 

3.1.2 Convection Section 

The convection section is 8.33 ft wide, 56 ft long and 14.5 ft high inside insulation 

dimensions. The convection section is used for steam generation and BFW 

services. The total waste heat recovery (absorbed) duty in the convection is 50.5 

MMBtu/hr. The hot flue gases leave the convection section at 448ºF. 

Convection Section 





Steam Generator 

The Steam Generator (SG) is designed for a absorbed duty of 43.95 MMBtu/hr. 

Saturated water flowrate of 574,227 lb/hr enters at 463°F and 510 psig. The SG 

coils are used to generate 55,986 lb/hr of steam at 465 psig. The calculated 

pressure drop is 45 psi. The fluid mass velocity through the SG coil is 249.7 

lb/sec.ft 2 . The finned tubes have a maximum tip temperature of 590°F. The average 

convective heat flux (Based on bare outside surface) is 6,940 Btu/hr.ft 2 . 

The steam generator has 36 bare tubes and 60 finned tubes. The tubes are 

arranged in concurrent manner. All the tubes are 4” NPS, Sch.80 and made of 

A106 Gr B material. The tubes are arranged in 8 rows and 12 tubes per row. The 

effective length of the tube is 56 ft. The tubes are arranged in 8 passes and placed 

at 8” x 8” triangular pitch. The finned tubes are made of CS material with 0.875” 

height, 0.105” thick and 4 FPI fin configuration. The total heat transfer area is 2,375 

ft 2 (bare) + 37,700 ft 2 (finned). 

Boiler Feed Water 

The Boiler Feed Water (BFW) coils are placed at the top of convection section. It is 

designed for a absorbed duty of 6.55 MMBtu/hr. It is used to heat 70,918 lb/hr of 

water from a temperature of 300ºF to 385ºF. The inlet and outlet pressures are 470 

psig and 465 psig respectively. The calculated pressure drop is 5 psi. The fluid 

mass velocity through the BFW coil is 123.4 lb/sec.ft 2 . The finned tubes have a 

maximum tip temperature of 415°F. The average convective heat flux (Based on 

bare outside surface) is 2,758 Btu/hr.ft 2 . 

The BFW coils consists of 36 finned tubes. The tubes are arranged in 

countercurrent manner. All the tubes are 4” NPS, Sch. 80 and made of SA 106 Gr 

B material. The tubes are arranged in 3 rows and 12 tubes per row. The effective 

length of the tube is 56 ft. The tubes are arranged in 2 passes and placed at 8” x 8” 

triangular pitch. The finned tubes are made of CS material with 0.875” height, 0.105” 

thick and 4 FPI fin configuration. The total heat transfer area is 22,620 ft 2 (finned). 

The convection casing is made of 3/16” thk. CS material. It is lined with a single 

layer of 5” thk. Kaolite 2200. The end tube sheets of the convection section are 

made of ½” thk. CS material and is lined with 4” thk. Kaolite 2200. The header boxes 

are made of 3/16” thk. CS material and is lined with 2” thk. Insulating concrete 

refractory. 





3.1.3 Offtake Ducts and Stack 

The flue gas leaving the convection section enters the 

stack through two offtake ducts and is discharged into 

the atmosphere. Each offtake duct has a cross-section 

of 9.14 ft x 5.47 ft. The flue gas velocity in the offtake 

duct is 11.3 ft/s. The breaching is lined with 3” thk. 

Kaolite 2200 and offtake ducts are lined with 2” thk. 

Kaolite 2200. 

The stack is located at the top of the convection section 

and is self-supported. The length of the stack is 120 ft 

and the inside insulation diameter is 11.21 ft. Top of 

stack elevation is 213 ft. The stack is provided with a 

multi-blade damper with pneumatic actuator to control 

the draft. The damper blade and shaft are made up of 

SS-304 material. The stack is lined with 2” thk. Kaolite 

2200. The flue gas duct from the adjacent Debutanizer 

Reboiler connects the Platformer heater stack 5 ft 

above the stack damper. The debutanizer flue gas duct 

diameter is 2’ -7”. 

Refer to FIS-483-CIS-1001 (Sheets 1 and 2 of 2) for Existing Design Coil and 

Insulation Summary. 

Refer to FIS-483-PFD-1001 for Existing Design Process Flow Diagram. 





3.1.4 Basis for Existing Design Simulation 

❖ Process data for the Platformer Heater is taken from heater data sheet. 

❖ Mechanical Data is taken from heater datasheet and General Arrangement 

Drawings. 

❖ The design case simulation is performed at fixed exit condition. 

❖ We have considered an emissivity of 1.0 for the radiant tubes as they are 

coated with ceramic. 

Table 8: LPCCR Rich Feed Design Case Simulation 

Parameter Unit Datasheet Simulation Output 

Total Absorbed Heat Duty MMBtu/hr 156.8 158.9 

Process Heat Duty (Absorbed, 

Hydrocarbon) 

MMBtu/hr 106.3 105.6 

Naphtha Flowrate MBPD - 18.2 

Recycle Gas Flowrate MMSCFD - 26.4 

Total Feed Flowrate Lb/hr 211,731 211,731 

Waste Heat Duty Absorbed 

(Steam) 

MMBtu/hr 50.50 53.36 

Radiant Section 

Radiant Absorbed Heat Duty MMBtu/hr 106.3 105.6 

No. 1 Inter Heater (1-44-B-2) 

Heat Duty, absorbed MMBtu/hr 37.46 37.49 

Heat Duty, absorbed % 23.89 23.59 

Charge Flow Rate Lb/hr 211,731 211,731 

Inlet Temperature °F 801.0 807.5 






Inlet Pressure psig 71.8 71.9 

Outlet Temperature °F 1,010 1,010 

Outlet Pressure psig 69.8 69.8 

Coil Pressure Drop psi 2.0 2.1 

Radiant Heat Transfer Area ft 2 3,722 3,723 

Average Radiant Section Heat 

Flux 

Btu/hr/ft 2 10,064 10,070 

Max Rad. Section Heat Flux Btu/hr/ft 2 14,090 18,778 

Fluid Mass Velocity lb/sec/ft 2 - 23.8 

Bridge Wall Temperature °F 1,500 1,452 

Maximum Inside Film 

Temperature 

Maximum Tube Metal 

Temperature 

°F - 1,113 

°F 1,130 1,134 

Volumetric Heat Release Btu/hr/ft 3 - 2,287 

















Flux 

Btu/hr/ft 2 9,075 9,073 





Temperature 


Temperature 

°F - 1,131 

°F 1,125 1,154 


No.2 Inter heater (1-44-B-3) 



Charge Flow Ra Lb/hr 211,731 211,731 












Average Rad. Section Heat Flux Btu/hr/ft 2 9,970 9,990 





Temperature 


Temperature 

°F - 1,122 

°F 1,125 1,148 













Flux 

Btu/hr/ft 2 7,605 7,193 










Temperature 


Temperature 

°F - 1,076 

°F 1,100 1,092 



Total Convection Absorbed 

Heat Duty 

Flue Gas Temp. Entering 


MMBtu/hr 50.50 53.36 

°F 1,500 1,491 

Steam Generation Coils 



Circulation Flow Rate lb/hr 574,227 574,227 

Inlet Temperature °F 463.0 456 


Outlet Temperature °F 463.0 462.7 

Outlet Pressure psig 465 465.0 

Coil Pressure Drop Psi 45.0 45.1 

Steam Generation Flow Rate lb/hr 55,966 57,049 

Heat Transfer Area (Bare) Ft 2 2,375 2,375 

Heat Transfer Area (Finned) Ft 2 37,700 37,702 






Average SG Coil Section Heat 

Flux (BOS) 

Btu/hr/Ft 2 6,939 7,351 

Fluid Mass Velocity lb/s/Ft 2 - 249.7 

Flue Gas Mass Velocity lb/s/Ft 2 0.258 0.300 

Flue Gas Pressure Drop in WC - 0.076 

Flue Gas Temperature Leaving 

SG Coil Section 

Outside Heat Transfer Fin 

Efficiency Factor 

°F - 555 

- - - 

Maximum Fin Tip Temperature °F 590 481.5 

Boiler Feed Water Coils 



Flow Rate Lb/hr 70,918 70,918 


Inlet Pressure Psig 470 470 

Outlet Temperature °F 385.0 391.6 

Outlet Pressure Psig 465.0 467.9 

Coil Pressure Drop Psi 5.0 2.1 

Heat Transfer Area (Finned) Ft 2 22,620 22,621 

Average BFW Coil Section Heat 

Flux (BOS) 

Btu/hr/Ft 2 2,758 2,863 

Fluid Mass Velocity Lb/s/Ft 2 - 123.4 

Flue Gas Mass Velocity Lb/s/Ft 2 0.258 0.300 

Outside Heat Transfer Fin 


- - - 

Flue Gas Pressure Drop in WC - 0.027 






Flue Gas Temperature Leaving 

BFW Coil Section 

°F 448 407 

Maximum Fin Tip Temperature °F 415 415 

Combustion 

Fuel Gas Heating Value (LHV) Btu/Scf 1,120 1,118 

Total Fuel Gas Flow Rate Lb/hr - 8,248 

Total Combustion Air Flow Rate Lb/hr - 159,224 

Combustion Air Temperature °F 60 60 

Total Flue Gas Flow Rate Lb/hr - 167,472 

Total Firing Rate MMBtu/hr 177.5 178.0 

Heat Loss % 2 2 

Thermal Efficiency % 88.3 89.3 


Fuel Gas Flow Rate Lb/hr - 2,873 

Combustion Air Flow Rate Lb/hr - 55,460 

Flue Gas Flow Rate Lb/hr - 58,333 

Firing Rate MMBtu/hr - 62.0 

Excess O2 % 3.00 3.00 

Excess Air % 15.0 15.0 











Excess O2 % 3.00 3.00 

Excess Air % 15.0 15.0 






Excess O2 % 3.00 3.00 

Excess Air % 15.0 15.0 


Fuel Gas Flow Rate Lb/hr - 996 




Excess O2 % 3.00 3.00 

Excess Air % 15.0 15.0 

3.1.5 Observations of Existing Design 

❖ The heat absorption in the radiant section is increased with high tube 

emissivity. 

❖ We are almost matching all the terminal conditions with the datasheet. 

❖ We are almost matching the bridge wall temperature with the datasheet. 

❖ Convection section flue gas exit temperature is 41°F lesser than the 

datasheet. 

❖ The amount of steam generation is almost matching with the datasheet 

value. 





3.1.6 Existing Heater Energy Balance 

The below table shows the energy balance across the radiant and convection 

section: 

Table 9: Existing Heater Energy Balance 


Parameter 

Unit 

Charge 

Heater 

No. 1 

Interheater 

No. 2 

Interheater 

No. 3 

Interheater 

Firing Rate MMBtu/hr 44.5 62.0 50.0 21.5 

Bridgewall 

temperature 

°F 1,512 1,452 1,552 1,418 

Flue Gas Enthalpy Btu/lb 415.3 396.6 427.8 386.1 

Flue Gas Flowrate Lb/hr 41,868 58,333 47,043 20,228 

Radiant Heat Loss % 2.0 2.0 2.0 2.0 

Radiant Duty, 

absorbed 

Total Radiant Duty, 

absorbed 


Flue Gas Conv. Inlet 

Temperature 

Flue Gas Conv. Outlet 

Temperature 

Enthalpy of Flue Gas 

at Conv. Inlet 

Enthalpy of Flue Gas 

at Conv. Outlet 

Total Flue Gas 

Flowrate 

Total Convection 

Duty, absorbed 

MMBtu/hr 26.20 37.63 28.88 13.26 

MMBtu/hr 105.97 

°F 1,491 

°F 406.9 

Btu/lb 408.8 

Btu/lb 92.27 

Lb/hr 167,472 


Steam Generated lb/hr 56,675 





3.2 Debutanizer Reboiler Description 

The Debutanizer Reboiler (1-44-B-5) is a vertical cylindrical, natural draft heater. 

The heater was originally built in 1992. It is located adjacent to the CCR Platformer 

heater (1-44-B-1/2/3/4). It has a horizontal convection section. The flue gases leave 

the convection section through a duct that combines to the Platformer Heater stack. 

The total absorbed heat duty of the heater is 10.16 MMBtu/hr. It is designed to heat 

124,436 lb/hr of debutanizer bottoms from 447°F to 504°F. The feed inlet pressure 

is 215 psig and the coil pressure drop is 50 psi. the inlet-outlet vaporization is 0% 

and 50% respectively. 

The calculated average radiant heat flux is 9,000 Btu/hr/ft 2 and the maximum 

radiant heat flux is 16,200 Btu/hr/ft 2 . The process fluid mass velocity is 172.3 

lb/sec/ft 2 . The maximum tube metal temperature is 555°F. The hot flue gases enter 

the convection section at 1,310°F and leave at 538°F. The maximum flue gas mass 

velocity through the convection section is 0.370 lb/sec.ft 2 . 

The heater is designed for fuel gas firing at 15% excess air. The firing rate of the 

heater is 11.81 MMBtu/hr. The calculated net thermal efficiency is 86% (based on 

LHV) considering a heat loss of 2%. 

The Debutanizer reboiler (1-44-B-5) consists of: 



Flue gas duct 

Burners 

3.2.1 Radiant Section 

The radiant section inside insulation height and diameter is 18.34 ft and 10.54 ft 

respectively. It consists of total 28 tubes of 6” NPS, Sch.40 arranged in single pass 

arrangement. The tubes are made of A106 Gr.B metallurgy. The tube circle 

diameter is 8.94 ft. The radiant effective tube length is 16.75 ft. the straight tube 

length is 15.17 ft. The total radiant section heat transfer area is 813 ft 2 . 

The radiant wall casing is made of 1/4” thk. CS material. The radiant shielded wall 

is lined with 6” thk. L.W. Castable Kaolite 2200. The radiant floor is lined with 8” thk. 

L.W. Castable Kaolite 2200. The radiant arch is lined with 6.5” thk. L.W. Castable 

Kaolite 2200. 

3.2.2 Convection Section 





The convection section is 2.09 ft wide and 11.25 ft long. It consists of total 18 tubes 

of 5” NPS, Sch. 40 arranged in single pass arrangement. The tubes are made of 

A106 Gr.B material. The tubes are arranged in 9 rows with 2 tubes in each row. It 

consists of 3 bare and 6 finned tube rows. The tubes are arranged in 10”X 10” 

triangular pitch. The effective tube length is 11.25 ft. The total heat transfer area for 

is 98 ft 2 (bare) + 1,926 ft 2 (finned). 

The convection section side walls are lined with 5” thk. L.W. Castable Kaolite 2200. 

The end tube sheets are provided with 3” thk. L.W. Castable Kaolite 2200. The 

breeching is lined with 3” thk. L.W. Castable Kaolite 2200. The header boxes are 

lined with 2” L.W. Castable Kaolite 2200. 

3.2.3 Flue Gas Duct 

Flue gases leaving the convection section enters into the Platformer Stack through 

the flue gas duct. The approximate length of this flue gas duct is 100ft. The 

debutanizer flue gas duct combines with the Platformer Stack at an elevation of 125 

ft. The flue gas duct inside insulation diameter is 2.58 ft. The design flue gas velocity 

is 16.5 ft/sec. 

The flue gas duct is internally lined with 2” thk. L.W. Castable Kaolite 2200. 

3.2.4 Burners 

The radiant section is fired with 3 natural draft, Ultra Low NOx burners. The burners 

are installed on the radiant floor. The burner circle diameter is 3.27 ft. The burner 

centerline to tube center line distance is 2.83 ft. Each burner is rated for 4.92 

MMBtu/hr of maximum heat release. The normal heat release per burner is 3.93 

MMBtu/hr. It has a turndown ratio is 3:1. The draft available is -0.25 in WC. 

Refer to FIS-483-CIS-1004 for Existing Debutanizer Reboiler Coil and 

Insulation Summary. 

Refer to FIS-483-SK-1001 for Debutanizer Reboiler Convection Off-take Duct 

Sketch. 





3.2.5 Basis for Existing Design Simulation 

❖ Process data for the Debutanizer Reboiler is taken from heater data sheet. 

❖ Mechanical Data is taken from heater datasheet and General Arrangement 

Drawings. 

❖ The design case simulation is performed at fixed exit condition. 

❖ We have considered an emissivity of 1.0 for the radiant tubes 





Table 10: Debutanizer Reboiler Design Case Simulation 

Parameter 

Unit 

Datasheet 

Design Case 

Simulation 

Total Heat Duty, 

absorbed 

MMBtu/hr 10.16 10.17 

Charge Flow Rate lb/hr 124,436 124,436 


Outlet Temperature °F 504.0 504 


Radiant Duty, absorbed MMBtu/hr - 6.89 

Radiant Duty, absorbed % - 67.75 

Radiant Heat Transfer 

Area 

Average Radiant Section 

Heat Flux 

Max Rad. Section Heat 

Flux 

Fluid Mass Velocity in 


ft 2 813 813 

Btu/hr/ft 2 9,000 8,475 

Btu/hr/ft 2 16,200 15,196 

lb/sec/ft 2 - 172.3 


Maximum Radiant Inside 

Film Temperature 

Maximum Radiant Tube 

Metal Temperature 

°F - 570.7 

°F 555 584.7 

Volumetric Heat Release Btu/hr/ft 3 19,855 10,439 






Parameter 

Unit 

Datasheet 

Design Case 

Simulation 

Convection Duty, 

absorbed 

Convection Duty, 

absorbed 

Conv. Heat Transfer Area 

(Bare) 


(Finned) 

Average Convection 

Section Heat Flux (BOS) 

MMBtu/hr - 3.28 

% - 32.25 

Ft 2 98 98 

Ft 2 1,926 1,737 

Btu/hr/Ft 2 - 11,054 

Fluid Mass Velocity lb/s/Ft 2 - 248.8 

Flue Gas Mass Velocity lb/s/Ft 2 - 0.465 

Flue Gas Pressure Drop In WC - 0.12 

Flue Gas Temp. leaving 

the coil section 

Maximum Fin Tip 

Temperature 

°F 538 569.3 

°F - 591.8 

Combustion 

Combustion Air Flow Rate lb/hr - 10,735 

Combustion Air 

Temperature 

°F 60 60 

Flue Gas Flow Rate lb/hr - 11,290 

Fuel Gas Flow Rate lb/hr - 555 

Fuel Gas Heating Value 

(LHV) 

Btu/Scf 1,120 1,120 





Parameter 

Unit 

Datasheet 

Design Case 

Simulation 

Excess O2 % - 2.99 

Excess Air % 15.0 15.0 

Total Firing Rate MMBtu/hr 11.81 11.99 

Heat Loss % 2.0 2.0 

Thermal Efficiency % 86.03 84.82 

3.2.6 Observations of Existing Design 

❖ We are almost matching all the terminal conditions with the datasheet. 

❖ Bridge Wall Temperature is higher than the datasheet. 

❖ Convection section flue gas exit temperature is 31°F higher than the 

datasheet. 





Section 4 

Current Data Analysis 

Marathon has provided operating data of 1 year for the Platformer heater from 2 nd 

November 2017 to 1 st November 2018. FIS carried out a detailed analysis of the 

data and the data is plotted with respect to time to observe the operating trend 

and variation with respect to the design value. 

4.1 Analysis from Graphs 

4.1.1 Feed Flowrate Analysis 

Table 11: List of Graphs of Feed 

Figure No. Parameters Tag no. 

Figure 1 Naphtha Charge Rate FC1 

Figure 2 Naphtha API Gravity 338033.A 

Figure 3 Naphtha Charge Rate Calculated 

Figure 4 Recycle gas Flow Rate FC2 

Figure 5 Recycle gas Flow Rate Calculated 

Figure 6 

Recycle Gas / Naphtha 

Flowrate Ratio 

Calculated 

Figure 7 Total Feed Flowrate Calculated 





Table 12 : Analysis of Feed Operating Data 

Description Units Max. Avg. Design 


Rate 

MBPD 24.5 22.9 18.2 

Naphtha API Gravity °API 61.1 59.6 60 


Rate 

Recycle gas Flow 

Rate 

Recycle gas Flow 

Rate 

Recycle Gas/Naphtha 

Flowrate Ratio 

Mlb /hr 267 244 196 

MMSCFD 38.5 32.3 26.4 

Mlb /hr 22.9 19.1 15.7 

lb/lb 0.34 0.08 0.08 

Total Feed Flowrate Mlb / hr 287.4 263.2 211.7 



FLOWRATE, MBPD 

API GRAVITY, ⁰API 



27 

25 

Figure 1: Naphtha Charge Rate, MBPD 

AVERAGE=22.9 MBPD 

DESIGN=18.2 MBPD 

(FC1) 

23 

21 

19 

17 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 TIME 

20-Aug-18 1-Nov-18 

Figure 2: Naphtha API Gravity, °API 

62 

AVERAGE=59.56 °API 

(338033.A) 

61 

60 

59 

58 

57 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



FLOWRATE, MLB/HR 

FLOWRATE, MMSCFD 



280 

260 

Figure 3: Naphtha Charge Rate, Mlb/hr 

AVERAGE=244.06 MLB/HR 

DESIGN =196.3 MLB/HR 

(CALCULATED) 

240 

220 

200 

180 


20-Aug-18 1-Nov-18 

40 

36 

Figure 4: Recycle Gas Flow Rate, MMSCFD 

AVERAGE=32.3 MMSCFD 

DESIGN=26.4 MMSCFD 

(FC2) 

32 

28 

24 

20 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



FLOW RATE RATIO, LB/LB 




Figure 5: Recycle Gas Flow Rate, Mlb/hr 

24 

22 


DESIGN=15.7 MLB/HR 

(CALCULATED) 

20 

18 

16 

14 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 

Note: Recycle Gas molecular weight of 5.41 lb/lbmol (provided for only one day in operating 

data) was considered in this calculation. 

Figure 6: Recycle Gas / Naphtha Flow Rate Ratio 

0.10 

AVERAGE=0.08 LB/LB 

(CALCULATED) 

0.09 

0.08 

0.07 

0.06 

0.05 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 






300 

280 

Figure 7: Total Feed Flow Rate to Each Cell 



(CALCULATED) 

260 

240 

220 

200 


20-Aug-18 1-Nov-18 

Observations on Feed Flowrate Graphs: 

❖ Operating process feed flow rate is 24.3% higher than the design. The 

average operating feed flow rate is 263,190 lb/hr and the design feed 

flowrate is 211,731 lb/hr. 





4.1.2 Charge Heater Analysis: 

Table 13: List of Graphs of Charge Heater 

Figure No. Parameters Tag No. 

Figure 8 Inlet Temperature TI3 

Figure 9 Outlet Temperature TC252 

Figure 10 Temperature Rise Calculated 

Figure 11 Charge Rate X ∆T Calculated 

Figure 12 Tube Metal Temperature TI552 

Figure 13 Bridge Wall Temperature TI204 

Figure 14 Bridge wall O 2 AI11C 

Figure 15 Fuel Gas Flow Rate FC53 

Figure 16 Fuel Gas Pressure PI169 

Figure 17 Firing Rate B1BTU.C 

Figure 18 

Firing Rate Based on Fuel 

Flow Rate 

Calculated 

Figure 19 Firing Rate Comparison - 

Figure 20 

Figure 21 

Charge Rate X ∆T Vs Firing 

Rate 

Bridge Wall Temperature Vs 

Firing Rate 

- 

- 





Table 14: Analysis of Operating Data of Charge Heater 

Description Units Maximum Average Design 

Inlet Temperature ºF 783 751 866 

Outlet Temperature ºF 946 911 1,010 

Temperature Rise ºF 175 161 144 

Charge Rate X ∆T Mlb°F/hr 48,212 42,120 30,489 

Tube Metal 

Temperature 

Bridge Wall 

Temperature 

ºF 1,089 1,017 1,125 

ºF 1,453 1,392 1,500 

Bridge wall O2 % 7.90 4.49 3.00 

Fuel Gas Flow Rate MMSCFD 1.58 1.44 0.96 

Fuel Pressure Psig 26.97 25.06 9.8 

Firing Rate MMBtu/hr 76.02 66.76 44.5 

Firing Rate Based on 

Fuel Flow Rate 


Fuel Gas Pressure 

MMBtu/hr 83.52 60.53 44.5 

MMBtu/hr 76.3 65.37 44.5 



TEMPERATURE, ⁰F 




900 

864 

Figure 8: Charge Heater Feed Inlet Temperature 

AVERAGE=751°F 

DESIGN=866°F 

(TI3) 

828 

792 

756 

720 


20-Aug-18 1-Nov-18 

1,020 

Figure 9: Charge Heater Feed Outlet Temperature 

(TC252) 

992 


DESIGN=1,010°F 

964 

936 

908 

880 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



CHARGE RATE x ΔT, MLB⁰F/HR 

TEMPERATURE RISE, ⁰F 



Figure 10: Charge Heater Temperature Rise 

180 

172 


DESIGN=144°F 

(CALCULATED) 

164 

156 

148 

140 


20-Aug-18 1-Nov-18 

Figure 11: Charge Rate × ∆T of Charge Heater 

50,000 

45,000 

AVERAGE=42,120 MLB°F/HR 

DESIGN=30,489 MLB°F/HR 

(CALCULATED) 

40,000 

35,000 

30,000 

25,000 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 




TEMPERATURE,⁰F 



1,180 

1,140 

Figure 12: Charge Heater Tube Metal Temperature 

AVERAGE=1,017 °F 

DESIGN =1,125 °F 

(TI552) 

1,100 

1,060 

1,020 

980 


20-Aug-18 1-Nov-18 

1,550 

1,500 

Figure 13: Flue Gas Temperature Leaving Charge Heater 

AVERAGE=1,392 °F 

DESIGN=1,500 °F 

(TI204) 

1,450 

1,400 

1,350 

1,300 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 




VOLUME % (DRY BASIS) 



Figure 14: Excess O2 at Charge Heater 

6.0 

(AI11C) 

AVERAGE=4.49 % 

DESIGN= 3 % 

5.3 

4.6 

3.9 

3.2 

2.5 


20-Aug-18 1-Nov-18 

Figure 15: Charge Heater Fuel Gas Flow Rate 

1.60 

(FC53) 

1.45 

1.30 



1.15 

1.00 

0.85 


20-Aug-18 1-Nov-18 

Note: The values in operating data is divided by 1,000 



PRESSURE, PSIG 

FIRING RATE, MMBTU/HR 



30.0 

Figure 16: Charge Heater Fuel Gas Pressure 

(PI169) 

25.5 

21.0 

AVERAGE=25.06 PSIG 

DESIGN=9.8 PSIG 

16.5 

12.0 

7.5 


20-Aug-18 1-Nov-18 

90 

80 

Figure 17: Charge Heater Firing Rate (Provided by Client) 

AVERAGE=66.76 MMBTU/HR 

DESIGN= 44.50 MMBTU/HR 

(B1BTU.C) 

70 

60 

50 

40 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







80 

72 

Figure 18: Charge Heater Firing Rate (from Fuel Flow Rate) 


DESIGN= 44.50 MMBTU/HR 

(CALCULATED) 

64 

56 

48 

40 


20-Aug-18 1-Nov-18 

Figure 19: Charge Heater Firing Rate Comparison 

100 

80 

60 

40 

20 

OPERATING DATA 

CALCULATED FROM FUEL FLOWRATE 

CALCULATED FROM FUEL PRESSURE 

0 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



CHARGE RATE x ΔT, MLB⁰F/HR 

TEMPERATURE, F 



Figure 20: Charge Rate × ∆T Vs Firing Rate of Charge Heater 

50,000 

(CALCULATED) 

45,000 

40,000 

35,000 

30,000 

DESIGN=30,489 MLB F/HR 

25,000 

35 45 55 65 75 85 


Figure 21: Charge Heater Bridge Wall Temperature Vs Firing Rate (Provided 

by Client) 

1,525 

(CALCULATED) 

1,470 

DESIGN=1,500 F 

1,415 

1,360 

1,305 

1,250 

40 48 56 64 72 80 






Observations on Charge Heater Graphs: 

❖ The heater is operating at 115 °F lower process feed inlet temperature than 

the design. The average operating process feed inlet temperature is 751°F 

and the design process feed inlet temperature is 866°F. 

❖ The process feed outlet temperature is lower than the design. The average 

operating process feed outlet temperature is 911°F and the design process 

feed outlet temperature is 1,010°F. 

❖ Average operating process feed temperature rise is higher than the design 

value by 20°F. 

❖ Burners are often operated at a higher fuel gas pressure than the design. 

The average operating fuel gas pressure is 25.06 psig which is higher than 

the design value of 9.8 psig. 

❖ in current operation, average excess O2 at arch is 4.49%, which is higher 

than the design value of 3%. 

❖ Bridge wall temperature is lesser than the design. The average bridge wall 

temperature is 1,392°F and the design bridge wall temperature is 1,500°F. 





4.1.3 No. 1 Inter Heater Analysis: 

Table 15: List of Graphs of No. 1 Inter Heater 








Figure 28 Bridge wall O2 AI11D 




Figure 32 Firing Rate Based on Fuel Flow Rate Calculated 


Figure 34 Charge Rate X ∆T Vs Firing Rate - 

Figure 35 Bridge Wall Temperature Vs Firing Rate - 





Table 16: Analysis of Operating Data of No. 1 Inter Heater 

Description Units Max. Avg Design 




Charge Rate X ∆T Mlb°F/hr 70,745 47,940 44,252 

Tube Metal 

Temperature 

Bridge Wall 

Temperature 

ºF 1,040 997.8 1,130 

ºF 1,393 1,356 1,500 

Bridge wall O2 % 7.58 4.38 3.00 








MMBtu/hr 96.46 69.94 62.0 

MMBtu/hr 86.1 74.45 62.0 





Figure 22: Inter Heater 1 Feed Inlet Temperature 

Figure 23: Inter Heater 1 Feed Outlet Temperature 





Figure 24: Inter Heater 1 Temperature Rise 

Figure 25: Charge Rate × ∆T of Inter Heater 1 





Figure 26: Inter Heater 1 Tube Metal Temperature 

Figure 27: Flue Gas Temperature Leaving Inter Heater 1 






Figure 28: Excess O2 at Inter Heater 1 Exit 

Figure 29: Inter Heater 1 Fuel Gas Flow Rate 

1.90 



(FC50) 

1.78 

1.66 

1.54 

1.42 

1.30 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







25 

Figure 30: Inter Heater 1 Fuel Gas Pressure 

(PI152) 

22 

19 


DESIGN=12 PSIG 

17 

14 

11 


20-Aug-18 1-Nov-18 

Figure 31: Inter Heater 1 Firing Rate (Provided by Client) 

100 

90 


DESIGN=62.0 MMBTU/HR 

(B2BTU.C) 

80 

70 

60 

50 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







100 

Figure 32: Inter Heater 1 Firing Rate (from Fuel Flow Rate) 

(CALCULATED) 


88 


76 

64 

52 

40 


20-Aug-18 1-Nov-18 

Figure 33: Inter Heater 1 Firing Rate Comparison 

100 

80 

60 

40 

20 




0 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 





Figure 34: Charge Rate × ∆T Vs Firing Rate of Inter Heater 1 

Figure 35: Inter Heater 1 Bridge Wall Temperature Vs Firing Rate (Provided 

by Client 





Observations on No.1 Inter heater Graphs 

❖ The heater is operating at a lower process feed inlet temperature than the 

design. The average operating process feed inlet temperature is 727°F and 

the design process feed inlet temperature is 801°F. 




❖ Average Operating process feed temperature rise is higher than the design 




the design value of 12 psig. 

❖ In current operation, average excess O2 at arch is 4.38% which is higher 








4.1.4 No. 2 Inter Heater Analysis 









Figure 42 Bridge wall O2 AI11B 












Table 18: Analysis of Operating Data of No. 2 Inter Heater 

Description Units Max Avg Design 




Charge Rate X ∆T Mlb ºF/hr 41,584 36,460 33,453 

Tube Metal Temp. ºF 1,060 1,006 1,125 

Bridge Wall Temp. ºF 1,431 1,374 1,500 

Bridge wall O2 % 9.53 4.47 3.00 








MMBtu/hr 80.15 56.18 50.0 

MMBtu/hr 74.50 62.61 50.0 


























1.60 

(FC56) 



1.49 

1.38 

1.27 

1.16 

1.05 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 








27 




(PI188) 

24 

21 

17 

14 

11 


20-Aug-18 1-Nov-18 

80 

72 




(B3BTU.C) 

64 

56 

48 

40 


20-Aug-18 1-Nov-18 







80 

70 




(CALCULATED) 

60 

50 

40 

30 


20-Aug-18 1-Nov-18 


100 

80 

60 

40 

20 




0 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







by Client) 





Observations on No.2 Inter heater Graphs: 

❖ The heater is operating at a lower process feed inlet temperature than the 






❖ Average operating process feed temperature rise is higher than the design 





❖ In current operation, average excess O2 at arch is 4.47%, which is higher 








4.1.5 No. 3 Inter Heater 









Figure 56 Bridge wall O2 AI11A 












Table 20: Analysis of Operating Data of No.3 Inter Heater 




Temperature Rise ºF 81.0 74.7 76.0 

Charge Rate X ∆T Mlb ºF/hr 22,841 19,710 16,092 

Tube Metal 

Temperature 

Bridge Wall 

Temperature 

ºF 1,053 1,004 1,100 

ºF 1,500 1,434 1,500 

Bridge wall O2 % 7.66 4.43 3.00 








MMBtu/hr 38.67 26.92 21.5 

MMBtu/hr 37.80 31.75 21.5 

























0.72 




(FC59) 

0.67 

0.61 

0.56 

0.50 

0.45 


20-Aug-18 1-Nov-18 








33 


(PI215) 

28 

24 



19 

15 

10 


20-Aug-18 1-Nov-18 

40 



DESIGN = 21.5 MMBtu/hr 

(B4BTU.C) 

36 

32 

28 

24 

20 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 








40 

35 


DESIGN=21.5 MMBtu/hr 

(CALCULATED) 

30 

25 

20 

15 


20-Aug-18 1-Nov-18 


100 


80 



60 

40 

20 

0 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







by Client) 





Observations on No.3 Interheater Graphs: 

❖ The heater is operating at 87°F lower process feed inlet temperature than 









❖ In current operation, average excess O2 at arch is 4.43%, which is higher 








4.1.6 Convection Section: 

Table 21: List of Graphs of Convection Section 


Figure 64 Saturated Water Flow Rate (MGPM) FI69 

Figure 65 Saturated Water Flow Rate (Mlb/hr) Calculated 

Figure 66 Total Steam Flow Rate FI68 

Figure 67 Boiler Feed Water Flow Rate FC65 

Figure 68 BFW Coil Inlet Temperature TI200B 

Figure 69 BFW Coil Outlet Temperature TI206 

Figure 70 BFW Coil Temperature Rise Calculated 

Figure 71 Average Bridge Wall Temperature Calculated 

Figure 72 Flue Gas Leaving Convection Section TI207 

Figure 73 Flue Gas Temperature Approach Calculated 

Figure 74 Flue Gas ΔT Across Convection Calculated 

Figure 75 Total Firing Rate Calculated 

Figure 76 Total Firing Rate Based on Fuel Flow Rate Calculated 

Figure 77 Total Firing Rate Comparison - 

Figure 78 

Flue Gas Temperature at Convection Exit Vs 

Total Firing Rate 

- 

Figure 79 Draft Profile at Entry of Convection PI245 

Figure 80 Excess O2 at Arch Calculated 

Figure 81 Stack Damper Position HC210.OP 





Table 22: Analysis of Operating Data of Convection Section 


Saturated Water 

Flow Rate 

Saturated Water 

Flow Rate 

Total Steam Flow 

Rate 

MGPM 1.91 1.55 1.15 

Mlb/hr 781.3 632.8 574.2 

Mlb/hr 69.30 57.48 55.97 

BFW Flow Rate GPM 173.84 140.36 141.63 

BFW Coil Inlet 

Temperature 

BFW Coil Outlet 

Temperature 

BFW Coil 

Temperature Rise 

Average Bridge Wall 

Temperature 

Flue Gas Leaving 


Flue Gas Temp. 

Approach 

Flue Gas ΔT Across 

Convection 

ºF 277 265 300 

ºF 370 345.7 385 

ºF 93 81 85 

ºF 1,435 1,389 1,500 

ºF 602 571 448 

ºF 337 306 148 

ºF 851.8 817.7 1,052 

Total Firing Rate MMbtu/hr 270.5 235.2 177.5 


Based on Fuel Flow 

Rate 


Based on Fuel Gas 

Pressure 

Draft at Entry of 

Convection 

MMbtu/hr 302 213.2 177.5 

MMBtu/hr 274.7 234.2 177.5 

In WC -0.17 -0.43 -0.10 

Excess O2 at Arch % 8.17 4.44 3.00 

Stack Damper 

Position 

% 33.35 25.8 - 



FLOW RATE, MLB/HR 

FLOW RATE, MGPM 



2.1 

Figure 64: Steam Generation Coil Circulation (MGPM) 

(FI69) 

1.9 

1.7 

1.5 

AVERAGE=1.55 MGPM 

1.3 

DESIGN=1.15 MGPM 

1.1 


20-Aug-18 1-Nov-18 

Figure 65: Steam generation Coil Circulation (Mlb/hr) 

800 

(CALCULATED) 

740 

680 



620 

560 

500 


20-Aug-18 1-Nov-18 





Figure 66: Flow Rate of Steam Generated 

Figure 67: Boiler Feed Water Flow Rate (GPM) 





Figure 68: BFW Coil Inlet Temperature 

Figure 69: BFW Coil Outlet Temperature 





Figure 70: BFW Coil Temperature Rise 

Figure 71: Average Flue Gas Temperature Leaving Radiant Section 






Figure 72: Flue Gas Temperature Leaving Convection Section 

Figure 73: Flue Gas Temperature Approach 

340 

(CALCULATED) 

300 

260 

AVERAGE=306 °F 

220 

DESIGN=148 °F 

180 

140 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 





Figure 74: Flue Gas ΔT Across Convection 

Observations on Convection Section Graphs 

❖ Total steam generated is closer to the design. The average steam 

generated is 57.48 Mlb/hr and the design steam generated is 55.97 

Mlb/hr. 

❖ The BFW inlet temperature is lower than the design. The average 

operating BFW inlet temperature is 265°F and the design BFW inlet 

temperature is 300°F. 

❖ The BFW outlet temperature is lower than the design. The average 

operating BFW outlet temperature is 346°F and the design BFW outlet 


❖ Platformer heater is operating at a lower efficiency than the design. The 

average flue gas exit temperature is 571°F and the design flue gas exit 


❖ Average flue gas temperature approach is higher than the design. The 

average approach is 306°F and the design approach is 148°F. 







Figure 75: Total Firing Rate (Provided by Client) 

320 

288 



(CALCULATED) 

256 

224 

192 

160 


20-Aug-18 1-Nov-18 

Figure 76: Total Firing Rate (from Fuel Flow Rate) 

300 

(CALCULATED) 



266 

232 

198 

164 

130 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







320 

Figure 77: Total Firing Rate Comparison 


260 

200 

140 

80 




20 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 20-Aug-18 1-Nov-18 

TIME 

Figure 78: Flue Gas Temperature at Convection Exit Vs Total Firing Rate 

600 

(CALCULATED) 

568 

536 

504 

472 

DESIGN= 448 F 

440 

150 180 210 240 270 300 

TOTAL FIRING RATE, MMBTU/HR 



PRESSURE, IN WC 

VOLUME % (DRY BASIS) 



Figure 79: Draft at Convection Entry 

-0.1 

-0.24 

AVERAGE=-0.43 IN WC 

DESIGN=-0.1 IN WC 

(PI245) 

-0.38 

-0.52 

-0.66 

-0.8 

2-Nov-17 13-Jan-18 27-Mar-18TIME 

8-Jun-18 20-Aug-18 1-Nov-18 

Figure 80: Average Excess O2 at Radiant Exit 

6.0 

5.3 

(CALCULATED) 


DESIGN= 3 % 

4.6 

3.9 

3.2 

2.5 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



DAMPER OPENING % 



Figure 81: Stack Damper Position 

33 


(HC210) 

30 

27 

24 

21 

18 


20-Aug-18 1-Nov-18 

Observations 

❖ The average total firing rate is 235.22 MMBtu/hr and the design total 

firing rate is 177.51 MMBtu/hr. 

❖ Overall Average excess O2 at arch is 4.44%. 





4.1.7 Fuel Data Analysis 

Table 23 : List of Graphs of Fuel 


Figure 82 Fuel Molecular Weight AL: 570500.E 

Figure 83 Fuel Net Heating Value Calculated 

Figure 84 

Fuel Molecular Weight Vs Fuel 

Heating Value 

Calculated 

Table 24: Analysis of Operating Data of Fuel 


Total Fuel Flow Rate MMSCFD 5.59 5.08 3.83 

Fuel Molecular 

Weight 

Lb / lbmol 26.48 18.73 19.61 

Fuel Heating Value Btu / Scf 1,363 1,007 1,120 



FUEL GAS HEATING VALUE(LHV), 

BTU/SCF 

MOLECULAR WEIGHT, LB/LBMOL 



27 

Figure 82: Fuel Gas Molecular Weight 

AVERAGE=18.73 LB/LBMOL 

DESIGN=19.61 LB/LBMOL 

(AL:570500.E) 

24 

21 

18 

15 

12 


20-Aug-18 1-Nov-18 

Figure 83: Fuel Gas Net Heating Value 

1,320 

AVERAGE=1,007 BTU/SCF 

DESIGN=1,120 BTU/SCF 

(CALCULATED) 

1,200 

1,080 

960 

840 

720 


20-Aug-18 1-Nov-18 



FUEL GAS MW, LB/LBMOL 



Figure 84: Fuel Gas Molecular Weight Vs Fuel Heating Value 

30 

(CALCULATED) 

26 

22 

DESIGN=19.61 LB/LBMOL 

18 

14 

10 

600 760 920 1080 1240 1400 

FUEL HEATING VALUE, BTU/SCF 





4.2 Current Operation Modeling 

Simulation of operating cases is done to determine how much the operating 

parameters deviate from the design data and to determine the effectiveness of the 

existing heat transfer surfaces. 

Basis for the Simulation 

To analyze the current operating conditions in detail, FIS has selected & simulated 

four operating cases as follows: 

1. DCS Case (06/25/18) 

2. Maximum Firing Case (06/11/18) 

3. Maximum Charge Case (08/30/18) 

4. Average Charge Case (04/13/18) 

The following operating data provided was assumed to be correct: 

a. Process parameters 

b. Stack temperature 

c. Excess O 2 % at exit of each radiant cell 

d. Fuel heating value 

e. Steam Generation 

f. BFW flow rates, inlet and outlet temperatures 

The operating simulations are also performed considering an emissivity of 1.0 for 

the radiant tubes. 





Parameter 


absorbed 

Process Heat Duty 

(Absorbed, 

Hydrocarbon) 

Table 25: Simulation of DCS Case (06/25/18) 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

MMBtu/hr 158.9 - 201.5 

MMBtu/hr 105.6 - 131.6 

Naphtha Flowrate MBPD 18.2 23.5 23.5 

Recycle Gas 

Flowrate 

Total Feed Flowrate Lb/hr 211,731 

Waste Heat Duty, 

Absorbed (Steam) 


Radiant Heat Duty, 

absorbed 


MMSCFD 26.4 36.0 36.0 

275,587 

(Calculated) 

275,587 

MMBtu/hr 53.36 - 69.91 

MMBtu/hr 105.6 - 131.6 

Heat Duty, absorbed MMBtu/hr 37.49 - 44.54 

Heat Duty, absorbed % 23.59 - 22.10 

Charge Flow Rate Lb/hr 211,731 275,587 275,587 

Inlet Temperature °F 807.5 720.0 721.2 

Inlet Pressure psig 71.9 86.3 87.0 

Outlet Temperature °F 1,010 913.0 913.0 

Outlet Pressure psig 69.8 84.3 84.3 

Coil Pressure Drop psi 2.1 2.0 2.7 

Radiant Heat 

Transfer Area 

Average Radiant 

Section Heat Flux 

ft 2 3,723 3,723 3,723 

Btu/hr/ft 2 10,070 - 11,963 





Parameter 

Max Rad. Section 

Heat Flux 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 2 18,778 - 21,792 

Fluid Mass Velocity lb/sec/ft 2 23.8 - 30.9 

Bridge Wall 

Temperature 


Temperature 

Maximum Tube 


Volumetric Heat 

Release 


Heat Duty, 

absorbed 

°F 1,452 1,375 1,511 

°F 1,113 - 1,018 

°F 1,134 981.5 1,044 

Btu/hr/ft 3 2,287 - 2,848 

MMBtu/hr 26.12 - 36.49 








Radiant Heat 

Transfer Area 




Heat Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,075 - 12,675 

Btu/hr/ft 2 12,700 - 27,684 

Fluid Mass Velocity lb/sec/ft 2 - - 30.9 

Bridge Wall 

Temperature 

°F 1,500 1,406 1,656 





Parameter 


Temperature 

Maximum Tube 



Release 


Heat Duty, 

absorbed 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F - - 1,052 

°F 1,125 975.5 1,085 

Btu/hr/ft 3 - - 4,030 

MMBtu/hr 28.76 - 31.53 








Radiant Heat 

Transfer Area 

Average Rad. 



Heat Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,990 - 10,952 

Btu/hr/ft 2 22,215 - 23,902 


Bridge Wall 

Temperature 


Temperature 

Maximum Tube 



Release 

°F 1,552 1,378 1,579 

°F 1,122 - 1,021 

°F 1,148 982.5 1,050 

Btu/hr/ft 3 2,807 - 3,273 





Parameter 


Heat Duty, 

absorbed 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

MMBtu/hr 13.22 - 19.05 








Radiant Heat 

Transfer Area 




Heat Flux 

ft 2 1,838 1,838 1,838 

Btu/hr/ft 2 7,193 - 10,365 

Btu/hr/ft 2 13,502 - 19,449 


Bridge Wall 

Temperature 


Temperature 

Maximum Tube 



Release 



Heat Duty, 

absorbed 


Entering Convection 

°F 1,418 1,459 1,545 

°F 1,076 - 997.1 

°F 1,092 1,009 1,020 

Btu/hr/ft 3 2,413 - 3,760 

MMBtu/hr 53.36 - 69.91 

°F 1,491 1,405 1,576 





Section 

Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 


Heat Duty, 

absorbed 

MMBtu/hr 46.56 - 57.75 


Circulation Flow 

Rate 

Lb/hr 574,227 

655,232 

(Calculated) 

655,232 

Inlet Temperature °F 456 - 449.1 

Inlet Pressure Psig 510.1 - 517.0 

Outlet Temperature °F 462.7 - 462.7 

Outlet Pressure Psig 465.0 - 465.0 

Coil Pressure Drop Psi 45.1 - 52.0 

Steam Generation 

Flow Rate 

Heat Transfer Area 

(Bare) 


(Finned) 

Average SG Coil 


(BOS) 

Lb/hr 57,049 62,700 71,985 

Ft 2 2,375 2,375 2,375 

Ft 2 37,702 37,702 37,702 

Btu/hr/Ft 2 7,351 - 9,118 

Fluid Mass Velocity Lb/s/Ft 2 249.7 - 379.9 

Flue Gas Mass 

Velocity 

Flue Gas Pressure 

Drop 

Flue Gas 

Temperature 

Leaving SG Coil 

Section 

Outside Heat 

Transfer Fin 

Lb/s/Ft 2 0.300 - 0.432 

in WC 0.076 - 0.158 

°F 555 - 765.7 

- - - 0.48 





Parameter 


Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 


Temperature 

°F 481.5 - 499.8 


Heat Duty, 

absorbed 

MMBtu/hr 6.55 - 12.16 


Flow Rate Lb/hr 70,918 

71,352 

(Calculated) 

75,584 


Inlet Pressure Psig 470 - 470.0 

Outlet Temperature °F 385.0 345.0 418.3 




(Finned) 

Average BFW Coil 


(BOS) 

Ft 2 22,620 22,621 22,621 

Btu/hr/Ft 2 2,758 - 5,120 


Flue Gas Mass 

Velocity 

Outside Heat 

Transfer Fin 



Drop 

Flue Gas 

Temperature 

Leaving BFW Coil 

Section 

Lb/s/Ft 2 0.258 - 0.432 

- - - 0.48 

in WC - - 0.062 

°F 448 584 583.2 





Parameter 


Temperature 

Combustion 

Fuel Gas Heating 

Value (LHV) 

Total Fuel Gas Flow 

Rate 

Total Combustion Air 

Flow Rate 


Temperature 

Total Flue Gas Flow 

Rate 


(LHV) 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 415 - 462.7 

Btu/Scf 1,118 1,259 1,258 

Lb/hr 8,248 11,322 12,592 

Lb/hr 159,224 - 228,450 

°F 60 - 60 

Lb/hr 167,472 - 241,042 

MMBtu/hr 178.0 262.0 239.7 

Heat Loss % 2 - 2 

Thermal Efficiency % 89.3 - 84.1 


Fuel Gas Flow Rate Lb/hr 2,873 3,745 4,056 

Combustion Air Flow 

Rate 

Lb/hr 55,460 - 72,012 

Flue Gas Flow Rate Lb/hr 58,333 - 76,068 


Excess O2 % 3.00 4.40 4.37 

Excess Air % 15.0 24.3 24.3 




Rate 

Lb/hr 39,806 - 68,708 





Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 



Excess O2 % 3.00 5.1 5.08 

Excess Air % 15.0 29.5 29.5 




Rate 

Lb/hr 44,726 - 56,657 



Excess O2 % 3.00 4.40 5.08 

Excess Air % 15.0 29.5 29.5 


Fuel Gas Flow Rate Lb/hr 996 1,464 1,760 


Rate 

Lb/hr 19,232 - 31,073 



Excess O2 % 3.00 4.30 4.27 

Excess Air % 15.0 23.6 23.6 





Table 26: Simulation of Maximum Firing Case (06/11/18) 

Parameter 


absorbed 


(Absorbed, 

Hydrocarbon) 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

MMBtu/hr 158.9 - 211.9 

MMBtu/hr 105.6 - 137.7 


Recycle Gas Flowrate MMSCFD 26.4 35.0 35.0 



absorbed (Steam) 


285,689 

(Calculated) 

285,689 

MMBtu/hr 53.36 - 74.18 


absorbed 

MMBtu/hr 105.6 - 137.7 






Inlet Pressure psig 71.9 - 92.4 



Coil Pressure Drop psi 2.1 - 2.8 


Area 

ft 2 3,723 3,723 3,723 





Parameter 




Flux 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 2 10,070 - 11,851 

Btu/hr/ft 2 18,778 - 21,590 


Bridge Wall 

Temperature 


Temperature 


Temperature 


Release 


°F 1,452 1,380 1,502 

°F 1,113 - 1,013 

°F 1,134 1,010 1,039 

Btu/hr/ft 3 2,287 - 2,815 










Area 




Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,073 - 13,376 

Btu/hr/ft 2 20,236 - 29,242 





Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 


Bridge Wall 

Temperature 


Temperature 


Temperature 


Release 


°F 1,512 1,425 1,684 

°F 1,131 - 1,063 

°F 1,154 1,028 1,099 

Btu/hr/ft 3 2,537 - 4,275 










Area 

Average Rad. Section 

Heat Flux 


Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,990 - 12,160 

Btu/hr/ft 2 22,215 - 26,546 


Bridge Wall 

Temperature 

°F 1,552 1,394 1,631 





Parameter 


Temperature 


Temperature 


Release 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 1,122 - 1,044 

°F 1,148 1,013 1,077 

Btu/hr/ft 3 2,807 - 3,616 











Area 




Flux 

ft 2 1,838 1,838 1,838 

Btu/hr/ft 2 7,193 - 10,903 

Btu/hr/ft 2 13,502 - 20,452 


Bridge Wall 

Temperature 


Temperature 


Temperature 

°F 1,418 1,473 1,572 

°F 1,076 - 1,009 

°F 1,092 995.3 1,034 





Parameter 


Release 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 3 2,413 - 4,074 


Total Convection Heat 




Section 

MMBtu/hr 53.36 - 74.18 

°F 1,491 1,418 1,600 




Circulation Flow Rate Lb/hr 574,227 

616,238 

(Calculated) 

616,238 


Inlet Pressure Psig 510.1 - 483.9 




Steam Generation Flow 

Rate 


(Bare) 


(Finned) 



(BOS) 

Lb/hr 57,049 64,193 76,326 

Ft 2 2,375 2,375 2,375 

Ft 2 37,702 37,702 37,702 

Btu/hr/Ft 2 7,351 - 9,755 


Flue Gas Mass Velocity Lb/s/Ft 2 0.300 - 0.447 





Parameter 


Drop 

Flue Gas Temperature 


Section 

Outside Heat Transfer 

Fin Efficiency Factor 


Temperature 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

in WC 0.076 - 0.168 

°F 555 - 767.5 

- - - 0.469 

°F 481.5 - 497.1 





73,087 

(Calculated) 

80,142 







(Finned) 



(BOS) 

Ft 2 22,621 22,621 22,621 

Btu/hr/Ft 2 2,863 - 5,221 






Drop 

- - - 0.469 

in WC 0.027 - 0.066 





Parameter 



Section 


Temperature 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 407 586 588.6 

°F 415 - 461.7 

Combustion 


(LHV) 


Rate 


Flow Rate 


Temperature 


Rate 

Btu/Scf 1,118 1,362 1,365 

Lb/hr 8,248 11,328 12,605 

Lb/hr 159,224 - 236,668 

°F 60 - 60 

Lb/hr 167,472 - 249,273 

Total Firing Rate MMBtu/hr 178.0 270.5 252.0 






Rate 

Lb/hr 55,460 - 71,257 



Excess O2 % 3.00 3.95 3.91 

Excess Air % 15.0 21.0 21.0 






Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 



Rate 

Lb/hr 39,806 - 71,664 



Excess O2 % 3.00 4.34 4.32 

Excess Air % 15.0 23.8 23.8 




Rate 

Lb/hr 44,726 - 59,398 



Excess O2 % 3.00 3.70 3.68 

Excess Air % 15.0 19.5 19.5 




Rate 

Lb/hr 19,232 - 34,349 



Excess O2 % 3.00 4.18 4.15 

Excess Air % 15.0 22.6 22.6 





Table 27: Simulation of Maximum Charge Case (08/30/18) 

Parameter 


absorbed 


(Absorbed, 

Hydrocarbon) 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

MMBtu/hr 158.9 - 207.9 

MMBtu/hr 105.6 - 134.7 


Recycle Gas 

Flowrate 


Waste Heat Duty , 




absorbed 


Heat Duty, 

absorbed 

MMSCFD 26.4 32 32 

283,420 

(Calculated) 

283,420 

MMBtu/hr 53.36 - 73.21 

MMBtu/hr 105.6 - 134.7 

MMBtu/hr 37.49 - 42.98 






Outlet Pressure psig 69.8 - 91.0 


Radiant Heat 

Transfer Area 

ft 2 3,723 3,723 3,723 





Parameter 




Heat Flux 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 2 10,070 - 11,544 

Btu/hr/ft 2 18,778 - 21,028 


Bridge Wall 

Temperature 

Maximum Inside 


Maximum Tube 



Release 


Heat Duty, 

absorbed 

°F 1,452 1,375 1,483 

°F 1,113 - 1,008 

°F 1,134 996.7 1,033 

Btu/hr/ft 3 2,287 - 2,763 

MMBtu/hr 26.12 - 36.19 



283,420 

(Calculated) 






Radiant Heat 

Transfer Area 




Heat Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,073 - 12,570 

Btu/hr/ft 2 20,236 - 27,438 






Parameter 

Bridge Wall 

Temperature 



Maximum Tube 



Release 

Unit 


Heat Duty, 

absorbed 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 1,512 1,417 1,638 

°F 1,131 - 1,039 

°F 1,154 1,004 1,073 

Btu/hr/ft 3 2,537 - 3,967 

MMBtu/hr 28.76 - 35.56 








Radiant Heat 

Transfer Area 

Average Rad. 



Heat Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,990 - 12,352 

Btu/hr/ft 2 22,215 - 26,978 


Bridge Wall 

Temperature 



Maximum Tube 


°F 1,552 1,417 1,637 

°F 1,122 - 1,051 

°F 1,148 1,018 1,084 





Parameter 


Release 

Unit 


Heat Duty, 

absorbed 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 3 2,807 - 3,779 

MMBtu/hr 13.22 - 19.97 








Radiant Heat 

Transfer Area 




Heat Flux 

ft 2 1,838 1,838 1,838 

Btu/hr/ft 2 7,193 - 10,865 

Btu/hr/ft 2 13,502 - 20,380 


Bridge Wall 

Temperature 



Maximum Tube 



Release 


°F 1,418 1,458 1,563 

°F 1,076 - 1,008 

°F 1,092 1,020 1,032 

Btu/hr/ft 3 2,413 - 4,085 


Heat Duty, 

MMBtu/hr 53.36 - 73.21 





Parameter 

absorbed 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 



Section 

°F 1,491 1,417 1,580 


Heat Duty, 

absorbed 

MMBtu/hr 46.56 - 60.69 


Circulation Flow 

Rate 

Lb/hr 574,227 

752,301 

(Calculated) 

752,301 






Steam Generation 

Flow Rate 


(Bare) 


(Finned) 



(BOS) 

Lb/hr 57,049 66,870 75,414 

Ft 2 2,375 2,375 2,375 

Ft 2 37,702 37,702 37,702 

Btu/hr/Ft 2 7,351 - 9,582 


Flue Gas Mass 

Velocity 


Drop 

Flue Gas 

Temperature 


Lb/s/Ft 2 0.300 - 0.448 

in WC 0.076 - 0.171 

°F 555 - 770.0 





Section 

Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Outside Heat 

Transfer Fin 



Temperature 


Heat Duty, 

absorbed 

- - - 0.488 

°F 481.5 - 501.3 

MMBtu/hr 6.80 - 12.52 



65,203 

(Calculated) 

79,185 


Inlet Pressure Psig 470 - 470 





(Finned) 



(BOS) 

Ft 2 22,621 22,621 22,621 

Btu/hr/Ft 2 2,863 - 5,271 


Flue Gas Mass 

Velocity 

Outside Heat 

Transfer Fin 



Drop 

Flue Gas 

Temperature 

Lb/s/Ft 2 0.300 - 0.448 

- - - 0.488 

in WC 0.027 - 0.067 

°F 407 589 591.3 





Parameter 


Section 


Temperature 

Combustion 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 415 - 482.9 

Fuel Gas Heating 

Value (LHV) 


Rate 

Total Combustion 

Air Flow Rate 


Temperature 


Rate 

Btu/Scf 1,118 1,186 1,189 

Lb/hr 8,248 11,691 12,247 

Lb/hr 159,224 - 237,631 

°F 60 - 60 

Lb/hr 167,472 - 249,878 

Total Firing Rate MMBtu/hr 178.0 270 248.5 






Rate 

Lb/hr 55,460 - 71,392 



Excess O2 % 3.00 3.96 3.94 

Excess Air % 15.0 21.0 21.0 







Parameter 


Rate 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Lb/hr 39,806 - 67,217 



Excess O2 % 3.00 4.20 4.18 

Excess Air % 15.0 22.6 22.6 




Rate 

Lb/hr 55,460 - 64,327 



Excess O2 % 3.00 3.91 3.91 

Excess Air % 15.0 20.8 20.8 




Rate 

Lb/hr 19,232 - 34,695 



Excess O2 % 3.00 3.94 3.94 

Excess Air % 15.0 21.0 21.0 





Table 28: Simulation of Average Charge Case (04/13/18) 

Parameter 


absorbed 

Process Heat Duty , 

absorbed 

(Hydrocarbon) 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

MMBtu/hr 158.9 - 195.1 

MMBtu/hr 105.6 - 128.5 


Recycle Gas Flowrate MMSCFD 26.4 36.0 36.0 





263,176 

(Calculated) 

263,176 

MMBtu/hr 53.36 - 66.60 


absorbed 

MMBtu/hr 105.6 - 128.5 











Area 

ft 2 3,723 3,723 3,723 





Parameter 


Heat Flux 


Flux 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Btu/hr/ft 2 10,070 - 10,881 

Btu/hr/ft 2 18,778 - 19,903 


Bridge Wall Temperature °F 1,452 1,373 1,459 


Temperature 


Temperature 

°F 1,113 - 1,028 

°F 1,134 1,024 1,052 

Volumetric Heat Release Btu/hr/ft 3 2,287 - 2,534 











Area 


Heat Flux 


Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,073 - 12,365 

Btu/hr/ft 2 20,236 - 27,176 





Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 




Temperature 


Temperature 

°F 1,131 - 1,085 

°F 1,154 1,046 1,118 












Area 


Heat Flux 


Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,990 - 12,261 

Btu/hr/ft 2 22,215 - 26,934 







Parameter 


Temperature 


Temperature 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 1,122 - 1,084 

°F 1,148 1,049 1,117 












Area 


Heat Flux 


Flux 

ft 2 1,838 1,838 1,838 

Btu/hr/ft 2 7,193 - 9,298 

Btu/hr/ft 2 13,502 - 17,450 




Temperature 


Temperature 

°F 1,076 - 1,017 

°F 1,092 1,023 1,038 





Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 



Total Convection Heat 




MMBtu/hr 53.36 - 66.60 

°F 1,491 1,413 1,567 




Circulation Flow Rate Lb/hr 574,227 

582,126 

(Calculated) 

582,126 







Rate 


(Bare) 


(Finned) 

Average SG Coil Section 

Heat Flux (BOS) 

Lb/hr 57,049 54,977 68,526 

Ft 2 2,375 2,375 2,375 

Ft 2 37,702 37,702 37,702 

Btu/hr/Ft 2 7,351 - 8,714 







Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

Flue Gas Pressure Drop in WC 0.076 - 0.140 


Leaving SG Coil Section 




Temperature 


°F 555 - 749 

- - - 0.486 

°F 481.5 - 497.4 




70,503 

(Calculated) 

71,952 







(Finned) 



Ft 2 22,621 22,621 22,621 

Btu/hr/Ft 2 2,863 - 4,804 





- - - 0.486 

Flue Gas Pressure Drop in WC 0.027 - 0.055 





Parameter 



Section 


Temperature 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 

°F 407 565 567.9 

°F 415 - 452.3 

Combustion 


(LHV) 

Btu/Scf 1,118 1,096 1,098 

Total Fuel Gas Flow Rate Lb/hr 8,248 10,421 11,359 


Flow Rate 


Temperature 

Lb/hr 159,224 - 213,356 

°F 60 - 60 

Total Flue Gas Flow Rate Lb/hr 167,472 - 224,715 







Rate 

Lb/hr 55,460 - 63,741 



Excess O2 % 3.00 3.51 3.52 

Excess Air % 15.0 18.3 18.3 






Parameter 

Unit 

Design 

Simulation 

Operating 

Data 

Simulation 

Output 



Rate 

Lb/hr 39,806 - 62,042 



Excess O2 % 3.00 3.57 3.57 

Excess Air % 15.0 18.6 18.6 




Rate 

Lb/hr 44,726 - 59,033 



Excess O2 % 3.00 3.12 3.11 

Excess Air % 15.0 15.8 15.8 




Rate 

Lb/hr 19,232 - 28,540 



Excess O2 % 3.00 4.00 3.99 

Excess Air % 15.0 21.3 21.3 





Operating Simulation Observations 

❖ Convection tubes are fouled on flue gas side. Fins in the convection section 

are only 50% efficient. This is leading to higher flue gas temperature. 

❖ Firing rates for design and the operating case are as follows. 

Description 

Actual (Datasheet/ 

Provided by Client) 

Firing rate, MMBtu/hr 

Calculated 

Design Case 177.5 178.0 

DCS Case (06/25/18) 262.0 239.7 

Maximum Firing Case 

(06/11/18) 

Average Charge Case 

(04/13/18) 

Maximum Charge Case 

(08/30/18) 

270.5 252.0 

233.0 230.4 

270.0 248.5 

• We are not able to match the steam generation in the operating cases. 





Section 5 

Recommendations 

Marathon intends to operate the heater at 24.5 MBPD Naphtha Charge rate and 

36-38 MMSCFD of recycle gas flowrate during maximum octane rate. FIS has 

considered 24.5 MBPD and 40 MMSCFD as total feed flow rate for the projected 

operating case. FIS proposes to increase the capacity of the heater based on FIS 

patented Split Flow Technology. The proposed total process absorbed heat duty 

with the new convection using Split Flow Technology is 191.7 MMBtu/hr. Existing 

heater process absorbed duty is 105.6 MMBtu/hr. The process absorbed duty at 

maximum charge rate is 134.7 MMBtu/hr. 

5.1 Split Flow Technology 

In a reformer heater with a split flow, the process stream is divided in two streams 

and heated in parallel. The main stream continues to be heated as before in the 

radiant section. The split flow stream is heated in the convection section to the outlet 

temperature. The split flow convection section is designed by balancing the heat 

transfer and pressure drop with the radiant stream. 

The split flow piping runs from the inlet manifolds to the new convection coils and 

then return the convection section outlet split flow piping back to the outlet manifold 

from the radiant. 

The flow control can be achieved by introducing a variable resistance in the form of 

a butterfly control valve for heaters designed with low process side pressure drop. 

The split stream outlet temperature can be controlled by adjusting the flow through 

the convection section. These parallelly heated streams are mixed downstream and 

sent to the reformer reactors. 

5.2 Energy balance for process heat recovery in convection 

section 

FIS has considered the permitted firing rate of 280 MMBtu/hr (LHV) for the 

proposed design basis. The below table shows the amount of process heat 

recovered in the convection section. 





Table 29 : Proposed Convection Section Energy Balance 

Parameter Unit Value 

Total Firing Rate MMBtu/hr 280 

Total Radiant Process 

Absorbed Duty 


Bridgewall Temperature °F 1,644 

Total Flue Gas Flow Rate lb/hr 277,645 

Process Coils 

Flue Gas Entry Temperature °F 1,644 

Flue Gas Exit Temperature °F 1,125 

Enthalpy of Flue Gas at Inlet Btu/lb 454.5 

Enthalpy of Flue Gas at 

Outlet 

Process Duty Absorbed in 


Btu/lb 295.7 


5.3 New Convection Section with Split Flow Technology 

FIS proposes to install a new convection section that accommodates process coils 

for the four radiant cells of Platformer Heater in the bottom portion of the convection 

section. Steam generation coils are accommodated on the top portion of convection 

Section. The heat transfer surface is optimized to achieve the total heat absorbed 

duty and to limit the firing rate. The summary of proposed case duty is as follows: 





Heater Section 

Proposed 

Heat Duty, 

Absorbed 

Proposed 

Radiant Duty, 

Absorbed 

Proposed 

Convection 

Duty, Absorbed 

MMBtu/hr 

No. 1 Interheater 66.13 49.22 16.91 

Charge Heater 50.08 39.31 10.77 



Total Process 

Absorbed Duty 

191.7 147.5 44.25 

Steam Generator 39.81 - 39.81 

BFW Preheat 9.82 - 9.82 

Debutanizer 

Absorbed Duty 

5.12 - 5.12 

5.4 Proposed Convection Section Design 

The new convection section is designed to cool the flue gases from 1,644°F to 

438°F. The proposed convection consists of 3 bare rows and 12 finned rows. Each 

row consists of 12 tubes. The following heat recovery sequence (in the order of 

decreasing flue gas temperature) will be adopted in the convection section (bottom 

to top): 

a. No.3 Interheater - Bottom 1 bare row 

b. Charge Heater – Next 2 bare rows 

c. No.2 Interheater - Next 1 finned row 

d. No.1 Interheater - Next 2 finned rows 

e. Steam Generator - Next 2 finned rows 

f. Debutanizer – Next 1 finned row 

g. Steam Generator - Next 3 finned rows 

h. Boiler Feed Water - Next 3 finned rows 

No.3 Interheater split flow coils 

The bottom row consists of 12 bare tubes of 4” NPS Sch.40 made of A335 Gr. P9 

material. The tubes are arranged in twelve passes. The No.3 Interheater split flow 

coils will be designed for a absorbed heat duty of 6.14 MMBtu/hr. The heat transfer 

area is 792 ft 2 (bare). The flue gas temperature leaving the coil section is 1,573 °F. 





Charge Heater split flow coils 

The next two rows consists of 24 bare tubes of 4” NPS Sch.40 made of A335 Gr.P9 

material. The tubes are arranged in twelve passes. The Charge heater split flow 

coils will be designed for absorbed heat duty of 10.77 MMBtu/hr. The heat transfer 

area is 1,583 ft 2 (bare). The flue gas temperature leaving the coil section is 1,449 

°F. 


The next row consists of 12 finned tubes of 4” NPS Sch.40 made of A335 Gr. P9 

material. The tubes are arranged in twelve passes. The No.2 Interheater split flow 

coils will be designed for absorbed heat duty of 10.43 MMBtu/hr. The fins are of 

0.5” ht. X 0.06” thk. X 5 FPI configuration and made of 18Cr-8 Ni fin material. The 

heat transfer area is 5,243 ft 2 (finned). The flue gas temperature leaving the coil 

section is 1,326°F. The maximum fin tip temperature is 1,147°F. 


The next two rows consists of 24 finned tubes of 4” NPS Sch.40 made of A335 Gr. 

P9 material. The tubes are arranged in twelve passes. The No.1 Interheater split 

flow coils will be designed for absorbed heat duty of 16.91 MMBtu/hr. The fins are 

of 0.75” ht. X 0.06” thk. X 5 FPI configuration and made of 18Cr-8Ni fin material. 

The heat transfer area is 15,596 ft 2 (finned). The flue gas temperature leaving the 

coil section is 1,125°F. The maximum fin tip temperature is 1,140°F. 

The preliminary manifold sizes for the process convection split flow coil are as 

follows: 

a. Charge Heater: 14” NPS 

b. No.1 Interheater: 16” NPS 

c. No.2 Interheater: 14” NPS 

d. No.3 Interheater: 16” NPS 

Lower Steam Generator coils 

The next two finned rows consist of 24 finned tubes of 4” NPS Sch.80 made of 

A106 Gr.B tube material. The tubes are arranged in six passes. The lower steam 

generator coils will be designed for absorbed heat duty of 25.5 MMBtu/hr. The fins 

are of 0.75” ht. X 0.06” thk. X 5 FPI configuration and made of CS fin material. The 


section is 81 °F. The maximum fin tip temperature is 606°F. 

Debutanizer coils 

The next finned row consists of 12 finned tubes of 4” NPS Sch.40 made of 





A106 Gr.B tube material. The tubes are arranged in four passes. The Debutanizer 

finned row is sandwiched between lower and upper steam generation coils. The 

outlet from the adjacent Debutanizer heater is heated in series with the debutanizer 

coil in the Platformer convection. The Debutanizer coil in the Platformer convection 

is designed for absorbed heat duty of 5.12 MMBtu/hr. It is designed to heat 75% of 

debutanizer process fluid (93,327 lb/hr) at 504°F. 

The fins are of 1” ht. X 0.06” X 5 FPI configuration and made of CS fin material. The 


section is 749°F. The maximum fin tip temperature is 693 °F. 

Upper Steam Generator coils 

The next three finned rows consist of 36 finned tubes of 4” NPS Sch.80 made of 

A106 Gr.B tube material. The tubes are arranged in six passes. The upper steam 

generator coils will be designed for absorbed heat duty of 14.32 MMBtu/hr. The fins 

are of 1” ht. X 0.06” thk. X 5 FPI configuration and made of CS fin material. The 

heat transfer area is 31,720 ft 2 (finned). The maximum fin tip temperature is 566 °F. 

BFW Coils 

The last three finned rows consist of 36 finned tubes of 4” NPS Sch.80 made of 

A106 Gr.B tube material. The BFW coils will be designed for absorbed heat duty of 

9.82 MMBtu/hr. The fins are of 1” ht. X 0.06” X 5 FPI configuration and made of CS 

fin material. The heat transfer area is 31,720 ft 2 (finned). The flue gas temperature 

leaving the coil section is 438°F. The maximum fin tip temperature is 476°F. 

The height of the proposed convection is increased by approximately 11-7/16”. The 

new top of stack elevation is 213.95 ft. 

The approximate weight of the existing and proposed convection section is 366,976 

lbs. and 395,226 lbs. respectively. The percentage increase in weight is 8%. 

Refer to FIS-483-CIS-1002 (Sheets 1& 2 of 2) for Proposed Design Coil and 

Insulation Summary and FIS-483-CIS-1003 for existing and proposed 

convection comparison. 

Refer to FIS-483-PFD-1002 for Proposed Process Flow Diagram. 





5.5 Proposed Design 3D Model 

3D snapshot of the proposed revamp with split flow inlet and outlet piping 

connecting radiant inlet and outlet transfer lines to convection process coils. 





Parameter 


Absorbed 


(Absorbed, 

Hydrocarbon) 

Table 30: Proposed Simulation Comparison 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

MMBtu/hr 158.9 207.9 246.5 

MMBtu/hr 105.6 134.7 191.7 


Recycle Gas Flowrate MMSCFD 26.4 32 40 

Total Feed Flowrate Lb/hr 211,731 283,420 288,160 

Debutanizer Heat Duty, 

Absorbed 


Absorbed (Steam) 

Total Radiant Heat 

Duty, Absorbed 


Process Absorbed Heat 

Duty 

MMBtu/hr - - 5.12 

MMBtu/hr 53.36 73.21 49.63 

MMBtu/hr 105.6 134.7 147.5 

MMBtu/hr - - 44.25 


Total Absorbed Heat 

Duty 

MMBtu/hr 37.49 42.98 66.13 


Heat Duty, absorbed MMBtu/hr 37.49 42.98 49.22 

Heat Duty, absorbed % 23.59 20.67 19.94 








Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 





Area 


Heat Flux 


Flux 

ft 2 3,723 3,723 3,723 

Btu/hr/ft 2 10,070 11,544 13,221 

Btu/hr/ft 2 18,778 21,028 24,562 

Fluid Mass Velocity lb/sec/ft 2 23.8 31.8 23.8 

Bridge Wall Temperature °F 1,452 1,483 1,575 


Temperature 


Temperature 

°F 1,113 1,008 1,126 

°F 1,134 1,033 1,154 

Volumetric Heat Release Btu/hr/ft 3 2,287 2,763 3,306 


Heat Duty Absorbed MMBtu/hr - - 16.91 

Heat Duty Absorbed % - - 6.85 

Charge Flow Rate Lb/hr - - 

76,250 

(26.4% split) 

Inlet Temperature °F - - 728.9 

Inlet Pressure Psig - - 71.8 

Outlet Temperature °F - - 987.4 

Outlet Pressure Psig - - 70.2 





Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

Fluid Pressure Drop Psi - - 1.6 

Convection Heat Transfer 

Area (Finned) 

Average Conv. Sec. Heat 

Flux (BOS) 

Ft 2 - - 15,596 

Btu/hr/Ft 2 - - 10,680 

Fluid Mass Velocity Lb/s/Ft 2 - - 20.0 

Flue Gas Mass Velocity Lb/s/Ft 2 - - 0.452 

Flue Gas Pressure Drop In WC - - 0.071 


the Coil Section 


Temperature 

°F - - 1,125 

°F - - 1,140 


Total Absorbed Heat 

Duty 

MMBtu/hr 26.12 36.19 50.08 


Heat Duty Absorbed MMBtu/hr 26.12 36.19 39.31 

Heat Duty Absorbed % 16.44 17.41 15.93 

Charge Flow Rate Lb/hr 211,731 

283,420 

(Calculated) 

223,580 










Parameter 


Area 


Heat Flux 


Flux 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,073 12,570 13,654 

Btu/hr/ft 2 20,236 27,438 30,287 




Temperature 


Temperature 

°F 1,131 1,039 1,134 

°F 1,154 1,073 1,170 






64,580 

(22.4% split) 







Area (Bare) 


Flux (BOS) 

Ft 2 - - 1,583 

Btu/hr/Ft 2 - - 6,804 





Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 







Total Heat Duty 

Absorbed 


°F - - 1,449 

MMBtu/hr 28.76 35.56 49.20 



Charge Flow Ra Lb/hr 211,731 283,420 222,080 







Area 


Heat Flux 


Flux 

ft 2 2,879 2,879 2,879 

Btu/hr/ft 2 9,990 12,352 13,466 

Btu/hr/ft 2 22,215 26,978 29,885 






Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 



Temperature 


Temperature 

°F 1,122 1,051 1,138 

°F 1,148 1,084 1,173 






66,080 

(22.9% split) 







Area (Finned) 


Flux (BOS) 

Ft 2 - - 5,243 

Btu/hr/Ft 2 - - 13,174 






°F - - 1,326 





Parameter 


Temperature 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

°F - - 1,147 



Absorbed 

MMBtu/hr 13.22 19.97 26.32 











Area 


Heat Flux 


Flux 

ft 2 1,838 1,838 1,838 

Btu/hr/ft 2 7,193 10,865 10,979 

Btu/hr/ft 2 13,502 20,380 20,591 




Temperature 


Temperature 

°F 1,076 1,008 1,056 

°F 1,092 1,032 1,080 





Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 






71,180 

(24.7% split) 







Area (Bare) 


Flux (BOS) 

Ft 2 - - 792 

Btu/hr/Ft 2 - - 7,753 






°F - - 1,573 

Heat Recovery Coils 


Absorbed Heat Duty 

(Process + Heat 

Recovery Coils) 

MMBtu/hr 53.36 73.21 99.0 





Parameter 



Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

°F 1,491 1,580 1,644 

Debutanizer Coils 



Charge Flow Rate Lb/hr - - 93,327 

Inlet Temperature °F - - 504 






(Finned) 

Average Convection 


Ft 2 - - 10,573 

Btu/hr/Ft 2 - - 6,467 





the coil section 


Temperature 

°F - - 748.5 

°F - - 693 







Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 


Circulation Flow Rate Lb/hr 574,227 752,301 752,301 

Inlet Temperature °F 456 450.8 472.5 

Inlet Pressure Psig 510.1 528.2 512.4 


Outlet Pressure Psig 465.0 465.0 465.0 

Coil Pressure Drop Psi 45.1 63.2 47.4 


Rate 


(Bare) 


(Finned) 

Average SG Coil Section 

Heat Flux (BOS) 

Lb/hr 57,049 75,414 53,061 

Ft 2 2,375 2,375 - 

Ft 2 37,702 37,702 47,316 

Btu/hr/Ft 2 7,351 9,582 10,057 

Fluid Mass Velocity Lb/s/Ft 2 249.7 436.2 436.2 

Flue Gas Mass Velocity Lb/s/Ft 2 0.300 0.448 0.475 

Flue Gas Pressure Drop in WC 0.076 0.171 0.103 


Leaving SG Coil Section 




Temperature 

°F 555 770.0 566.2 

- - 0.488 - 

°F 481.5 501.3 605.5 







Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 


Flow Rate Lb/hr 70,918 79,185 65,200 


Inlet Pressure Psig 470 470 470.0 


Outlet Pressure Psig 467.9 468.2 469 

Coil Pressure Drop Psi 2.1 1.8 1.0 


(Finned) 



Ft 2 22,621 22,621 31,720 

Btu/hr/Ft 2 2,863 5,271 4,135 

Fluid Mass Velocity Lb/s/Ft 2 123.4 113.4 113.4 

Flue Gas Mass Velocity Lb/s/Ft 2 0.300 0.448 0.475 



- - 0.488 - 

Flue Gas Pressure Drop in WC 0.027 0.067 0.057 



Section 


Temperature 

°F 407 591.3 438.1 

°F 415 482.9 476.3 

Combustion 


(LHV) 

Btu/Scf 1,118 1,189 1,120 

Total Fuel Gas Flow Rate Lb/hr 8,248 12,247 12,972 





Parameter 


Flow Rate 


Temperature 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

Lb/hr 159,224 237,631 264,673 

°F 60 60 60 

Total Flue Gas Flow Rate Lb/hr 167,472 249,878 277,645 


Heat Loss % 2 2 2 

Thermal Efficiency % 89.3 83.7 88.0 




Rate 

Lb/hr 55,460 71,392 84,423 

Flue Gas Flow Rate Lb/hr 58,333 75,083 88,574 


Excess O2 % 3.00 3.94 3.94 

Excess Air % 15.0 21.0 21.0 




Rate 

Lb/hr 39,806 67,217 74,274 



Excess O2 % 3.00 4.18 4.19 





Parameter 

Unit 

Design 

Simulation 

Maximum 

Charge 

Operating 

Case 

Proposed 

Simulation 

Excess Air % 15.0 22.6 22.6 




Rate 

Lb/hr 44,726 64,327 71,302 



Excess O2 % 3.00 3.91 3.91 

Excess Air % 15.0 20.8 20.8 




Rate 

Lb/hr 19,232 34,695 34,674 



Excess O2 % 3.00 3.94 3.96 

Excess Air % 15.0 21.0 21.0 





5.6 Effect of Charge Rate on the proposed design with split flow convection 

section 

When the heater operates at reduced loads (75% load and 50% load) for the same 

terminal conditions, the performance of the proposed design with split flow coils in 

convection is as follows: 

Parameter Units 100% Load 75% Load 50% Load 


Absorbed 

Total Charge 

Rate 

MMBtu/hr 246.5 186.6 122.8 

lb/hr 288,160 216,120 144,080 


Total Process 

Absorbed Heat 

Duty 

MMBtu/hr 191.7 147.4 98.8 

Bridgewall temp. °F 1,638 1,526 1,373 

Waste heat duty 

Absorbed 

MMBtu/hr 49.63 35.45 21.71 

Steam Generated lb/hr 53,061 37,901 23,211 

Debutanizer 

Absorbed duty 

MMBtu/hr 5.12 3.72 2.28 

Stack temp. °F 438.1 410.5 380.1 

Inter Heater 1 

Parameter Units Radiant Conv. Radiant Conv. Radiant Conv. 

Total Process 

Absorbed Duty 

Process Heat 

Duty Absorbed 

Charge Rate lb/hr 211,910 

Inlet / Outlet 

temp. 

MMBtu/hr 66.13 49.93 33.11 

MMBtu/hr 49.22 16.91 39.24 10.69 28.11 5.00 

76,250 

(26.46%) 

168,930 

47,190 

(21.84%) 

121,955 

22,125 

(15.36%) 

°F 717.2 / 988.7 717.2 / 988.7 719.4 / 988.7 





Coil pressure 

drop 

psi 2.0 1.6 1.3 0.6 0.7 0.1 

Charge Heater 


Total Process 

Duty Absorbed 

Process Heat 

Duty Absorbed 



temp. 

Coil pressure 

drop 


MMBtu/hr 50.08 39.23 26.04 

MMBtu/hr 39.31 10.77 31.63 7.60 21.54 4.50 

64,580 

(22.41 %) 

174,685 

41,435 

(19.17%) 

118,790 

25,290 

(17.55%) 

°F 739.8 / 953.0 733.1 / 953.0 732.8 / 953.0 

psi 1.3 0.8 0.8 0.3 0.4 0.1 


Total Process 

Duty Absorbed 

Process Heat 

Duty Absorbed 



temp. 

Coil pressure 

drop 


MMBtu/hr 49.20 37.73 25.59 

MMBtu/hr 38.77 10.43 31.12 6.61 22.50 3.09 

66,080 

(22.93 %) 

176,560 

39,560 

(18.30%) 

126,040 

18,040 

(12.52%) 

°F 796.0 / 990.0 794.1 / 990.0 791.5 / 990.0 

psi 2.2 0.8 1.4 0.3 0.7 0.1 


Total Process 

Duty Absorbed 

Process Heat 

Duty Absorbed 

MMBtu/hr 26.32 20.51 14.07 

MMBtu/hr 20.18 6.14 16.12 4.39 11.44 2.63 

Charge Rate lb/hr 216,980 71,180 172,735 43,385 118,490 25,590 





(24.70%) (20.07%) (17.76%) 


temp. 

Coil pressure 

drop 

°F 852.5 / 954.0 852.1 / 954.0 848.6 / 954.0 

psi 1.8 1.1 1.2 0.4 0.6 0.1 

5.6.1 Proposed Design Simulation Observations: 

Keeping the terminal conditions fixed, 

❖ At 100% load, percentage flow through the split flow coils in the convection 

section is in the range of 22.9 – 26.5%. 


section is in the range of 18.3 – 21.8%. 


section is in the range of 12.5-17.8%. 






5.7 Salient Features of Revamp Model 

Figure 85: Bridgewall Temperature Comparison 

2,000 

EXISTING DESIGN SIMULATIONS 

EXISTING HEATER AT PROPOSED CONDITIONS 

PROPOSED OPTION (NEW CONVECTION) 

Charge Heater Inter Heater No.2 

Inter Heater No. 3 

1,800 

Inter Heater No.1 

1,600 

1,400 

1,200 

1,000 

If the existing heater is operated at projected conditions, the bridgewall 

temperatures in all cells will be very high. For the projected operating 

condition, the estimated bridge wall temperature in No.1 Interheater is 

1,729°F, Charge heater is 1,849°F, No.2 Interheater is 1,855°F and No.3 

Interheater is 1,761°F. In proposed heater, the bridgewall temperatures will 

be 154°F lower in No.1 Interheater, 150°F lower in Charge heater, 157°F 

lower in No.2 Interheater and 183°F lower in No.3 Interheater. 

With the proposed design, the bridge wall temperatures will be reduced 

significantly in all cells. 






Figure 86: Firing Rate Comparison 

150 

120 





Charge Heater 


90 

60 


30 

0 

If existing heater is operated at projected conditions, the firing rate in each 

cell will be very high. With proposed option firing rate in No.1 Interheater is 

31% lower, in Charge Heater is 30% lower, in No.2 Interheater is 31.7% 

lower and in No.3 Interheater is 36.6% lower. The total firing rate in the 

proposed design will be 32% lower. 






Figure 87: Flue Gas Convection Exit Temperature 




800 

700 

600 

500 

400 

300 

The average flue gas convection exit temperature for the operating cases is 590°F. 

The estimated flue gas convection exit temperature for the existing heater at 

proposed condition is 722°F. The flue gas convection exit temperature for the 

proposed design is 438°F. 





Section 6 

Cost Estimation 

This section provides cost estimate (± 30%) for the revamp of Platformer Heater (1- 

44-B-1/2/3/4). It also provides the details of design, engineering, materials, 

fabrication and erection activities considered for the revamp work. 

6.1 Basis of Cost Estimation 

The cost estimate provided here is based on the following assumptions: 

❖ Construction prices are based on the USGC (US Gulf Coast) labor. 

❖ Heater Steel and Coil Fabrication, refractory installation and dry-out of the 

refractory wherever applicable are included in the cost estimate. 

❖ Crane, scaffolding, piping, and instrumentation cost is included wherever 

applicable. 

❖ Transportation cost up to the refinery is included 

❖ The removal of dumpsters, final disposal of removed tubes, casing, etc. are 

not included. 

❖ The heater would be blinded, isolated, opened and closed by others 

❖ No new foundation or civil work is anticipated in this revamp 

6.2 Proposed Design: New Convection Section 

Proposed Design consists of replacement of existing convection section with a new 

convection section. It consists of split flow coils, waste heat recovery coils and 

debutanizer coils. The convection section height is ~1 ft more than the existing 

convection section. New convection section will be supplied in two modules. New 

debutanizer flue gas duct module will be supplied. The existing convection 

platforms will be reused. As the convection height is increased, new debutanizer 

reboiler flue gas duct module and a ladder will be supplied. 





6.2.1 Scope of Supply 

The following items are considered as prefabricated and supplied to the site for 

installation: 

❖ New convection modules complete with coils, supports, refractory and 

manifolds 

❖ New refractory lined debutanizer flue gas duct module 

❖ New piping, valves and other hardware for split flow inlet and outlet lines 

tying between the new convection and existing radiant process inlet and 

outlet lines. 

6.2.2 Scope of Site Activity 

The following major site activities are envisaged: 

❖ Demolish existing debutanizer reboiler flue gas duct to platformer stack 

(Partially) 

❖ Dismantle existing platformer off take ducts and platforms 

❖ Dismantle existing platformer stack with platforms 

❖ Demolish existing convection modules, platforms (Reusable) and structures 

❖ Install new convection modules and structures 

❖ Re-install existing convection platforms with new ladder 

❖ Re-install existing platformer stack with platforms and ladders 

❖ Re-install existing off take ducts and platforms 

❖ Install new debutanizer reboiler flue gas duct module to platformer stack 

❖ Install split flow piping and valves 

6.2.3 Revamp Cost Estimate 

The cost estimates for increasing the capacity and improving efficiency in 

platformer heater is summarized below: 

S. No. Description 

Cost 

(Million USD) 

1 Convection Pressure Parts, Finning and Coil Fabrication 1.01 

2 Convection Intermediate Tube Sheets 0.40 

3 Steel fabrication, Refractory & Anchors 1.31 

4 

Split Flow Piping, Flow Control Valves and 

Instrumentation 

1.00 

Total Supply Cost (Hardware Cost) 3.72 



5 



Dismantling and erection, of convection modules and 

split flow piping (50% of Supply Cost) 

1.86 

6 Crane & rigger (45% of Supply Cost) 1.67 

7 Scaffolding (15% of Supply Cost) 0.56 

Total Direct Cost (Supply + Erection) 7.81 

8 Contingency (10% of Direct Cost) 

0.78 

9 Design, Engineering and Licensing Fee 1.40 

Total Cost 9.99 

6.2.4 Project Schedule 

❖ Convection Design, Engineering, Procurement and Shop Fabrication will 

require 10 to 12 months 

❖ Site Installation will require approx. 35 working days with 2 nos of 12-hour 

work shifts 





7.1 List of P & ID’s 

Section 7 

Appendix 

S. No Description Drawing No. 

1 P&ID LPCCR Platformer 14968 Sheet 02 

2 

P&ID LPCCR Platformer - Steam Generator 


3 P&ID LPCCR Platformer – Firing Controls 

14968 Sheet 22 

14968 Sheet 

17/18/19/20 

7.2 List of Documents & Drawings 

S. No Description Document No. 

1 Heater Datasheet - 

2 Burner Datasheet 

CA-BU-S87636-801 

to 819-0 

3 Capacity-Pressure Curve for Burners - 

4 44B5 Debut Reboiler Burner Data Sheet - 

5 44B5 Debut Reboiler Specification Sheet - 

6 44B5 Debut Reboiler Burner Curve II - 

7 44B5 Debut Reboiler Burner Curve I - 

8 DCS Print Outs & PI Screenshots - 

9 

10 

11 

12 

Convection Section Photos, Burner Photos, 

Refinery Pictures 

Heater General Arrangement Drawing- 

Longitudinal Section 

Heater General Arrangement Drawing-Cross 

Section 

Heater General Arrangement Drawing-Plan & 

Details 

- 

1131-1-6-2 E 

1131-1-6-3 B 

1131-1-6-4 C 






13 Bill of Material 1131-1-6-5E/4C 

14 Burner Arrangement-Longitudinal Sections 113137 

15 

16 

17 

18 

19 

Burner General Arrangement (Charge Heater 

Burners) 

Burner General Arrangement (Interheater-1 

Burner) 


Burner) 


Burner) 

ST-1-SE-FR SPL Pilot Assembly for Burners 

S87636-614/610-617619 

B-BU-S87636- 

607/608/611/612/61 

3/614 

B-BU-S87636- 

601/602/603/604/60 

5/606/610 

B-BU-S87636- 

609/615/616/617 

B-BU-S87636- 

618/619 

SB7636-620 

20 Steel Arrangement Radiant Section 1133-1-6-7B 

21 

(1-44-B-1, B-3) Radiant Coils & Headers (1992) 

Radiant Coil Arrangement 

1131-1-6-10-B 

22 (1-44-B-2, B-4) Radiant Coil Arrangement 1131-1-6-9-A 

23 Radiant Coil Arrangement for 1-44-B-1/2/3/4 46314 

24 General Notes & Coil Fabrication Notes 113306 

25 

26 

27 

28 

29 

Radiant Coils & Headers Wicket Pipe Bending 

Details 

(1-44-B-, B-2, B-3, B-4) Anchor Details for 

Radiant Arch Roof/End Walls/Floor/Radiant Wall 

Panels/Convection Section (Insulation & Anchor 

Details) 

(1-44-B-1, B-2, B-3, B-4) Insulation & Anchor 

Details for Radiant to Convection Section Duct 

(1-44-B-1, B-2, B-3, B-4) Steel Arrangement - 

Radiant to Convection Ducts 

(1-44-B-1, B-2, B-3, B-4) Radiant Coils & 

Headers (1992) Typical Details - Radiant & 

Convection Header Boxes 

CN-12-339-03- 

01/02/03/04 

- 

- 

1131-1-6-21-D 

121S-1-95M 

30 Steel Arrangement – Convection Section 1133-1-6-8F 






31 

32 

33 

(1-44-B-, B-2, B-3, B-4) Steel Arrangement 


(1-44-B-1, B-2, B-3, B-4) Steel Arrangement - 

Typical Details End Tube Sheet for Convection 

Section 

(1-44-B-1, B-2, B-3, B-4) Convection Section - 

Intermediate Tube Support - Alloy Casting 

1131-1-6-20-D 

121S-2-266M 

1131-1-6-7-A 

34 Finned Tube Details 113305 

35 Finned Tube Details 1133-4-6-5B 

36 General Arrangement Elevation and Section 113302 

37 General Arrangement Plan 113303 

38 Steel Fabrication General & Erection Notes 113310 

39 Steel Arrangements Plans – Platforms 1133-1-6-9C 

40 Foundation Loading Diagram 113301 

41 Miscellaneous Duct Details 121S1459 

42 Debutanizer Reboiler Flue Gas Duct to Stack 113132 





Appendix-1 

(Debutanizer Reboiler Operating Plots) 





Table 31 : List of Graphs of Debutanizer Reboiler 

Figure 

No. 

Parameters 

Tag No. 

Figure 88 Reboiler Duty Absorbed B5BTU.C 

Figure 89 Charge Flowrate FC20 



Figure 92 Draft at Convection Exit PI234 

Figure 93 Excess O2 at Stack AI11E 

Figure 94 Debutanizer Stack Damper Opening % HC196.OP 

Figure 95 Reboiler Stack Temperature TI130 

Figure 96 Fuel Gas Flowrate FC62 

Figure 97 Fuel Gas Pressure PC238 





Table 32: Analysis of Operating Data of Debutanizer Reboiler 


Reboiler Duty Absorbed MMBtu/hr 16.17 13.96 10.16 

Charge Flowrate MBPD 10.66 10.26 13.55 

Inlet Temperature °F 388.2 374.8 447 

Outlet Temperature °F 419.5 408.5 504 

Draft at Convection Exit In WC -0.04 -0.27 -0.1 

Excess O2 at Stack % 7.04 4.62 3.0 

Stack Damper Opening % % 65.5 56.57 - 

Stack Temperature °F 797.9 754.7 - 

Fuel Gas Flowrate MSCFD 350.8 306.9 - 

Fuel Gas Pressure PSIG 22.04 18.75 20 



FLOWRATE, MBPD 

HEAT CONTENT, MMBTU/HR 



Figure 88 : Reboiler Duty Absorbed 

16.0 

(B5BTU.C) 

14.4 

12.8 

11.2 



9.6 

8.0 


20-Aug-18 1-Nov-18 

Figure 89: Debutanizer Reboiler Charge Flowrate 

10.70 

10.55 

AVERAGE= 10.26 MBPD 

DESIGN=13.55 MBPD 

(FC20) 

10.40 

10.25 

10.10 

9.95 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 







Figure 90: Debutanizer Reboiler Inlet Temperature 

385 

381 

AVERAGE= 375°F 


(TI64) 

377 

373 

369 

365 

2-Nov-17 13-Jan-18 27-Mar-18TIME 

8-Jun-18 20-Aug-18 1-Nov-18 

Figure 91: Debutanizer Reboiler Outlet Temperature 

420 

416 

AVERAGE= 408 °F 


(TC66) 

412 

408 

404 

400 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



O 2 CONTENT, % 



Figure 92: Draft at Convection Exit 

0.0 

AVERAGE= -0.27 IN WC 

(PI234) 

-0.1 

PRESSURE, IN WC 

-0.2 

-0.3 

-0.4 

-0.5 


20-Aug-18 1-Nov-18 

Figure 93 Excess O2 at Stack 

6.5 

AVERAGE= 4.62 % 

DESIGN=3% 

(AI11E) 

5.7 

4.9 

4.1 

3.3 

2.5 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



DAMPER OPENING, % 




Figure 94: Debutanizer Stack Damper Opening Percentage 

70 

AVERAGE= 56.6 % 

(HC196.OP) 

65 

60 

55 

50 

45 


20-Aug-18 1-Nov-18 

Figure 95 : Reboiler Stack Temperature 

800 

(TI130) 

740 

680 

AVERAGE= 755 °F 

DESIGN=538°F 

620 

560 

500 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18 



FLOW RATE, MSCFD 




360 

AVERAGE= 306.9 MSCFD 

Figure 96 : Fuel Gas Flowrate 

(FC62) 

340 

320 

300 

280 

260 


20-Aug-18 1-Nov-18 

24.0 

21.6 

Figure 97 : Fuel Gas Pressure 

(PC238) 

AVERAGE= 18.75 PSIG 

DESIGN= 13.5 PSIG 

19.2 

16.8 

14.4 

12.0 

2-Nov-17 13-Jan-18 27-Mar-18 8-Jun-18 

TIME 

20-Aug-18 1-Nov-18

FIS-483 Engineering Study Report R1.03.11.19

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