Novel Design of an Integrated Pulp Mill Biorefinery for the ...

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Table 28: Quality requirements for gas turbine fuel gas. Gas characteristic Minimum LHV Particles Alkali metals Unit of measure MJ/Nm 3 ppm ppm Level 3–11 < 2-30 < 0.2-1.0 3. Combustion stability in Gas Turbine Stigsson [108] and Larson [109] noted that from the experience accumulated in Integrated Gasification Combined Cycles (IGCC) and experimental work, combustion stability is not a major issue when the fuel calorific value is above 4-6 MJ/m 3 n (at normal conditions of 1 atm, 0°C). Syngas produced with pure oxygen gasification has a heating value of 8-20 MJ/m 3 n. In our design considered, no particular flame stability problems are envisaged. 4. Steam Turbine: There are two basic steam turbine designs: back pressure and condensing. We chose back pressure steam turbine and let the steam leaving the turbine go into the steam distribution system to meet the steam requirement from pulp/paper process demand. 3.5.4 Design Main Issues 1. Recovery Heat from Syngas Cooling In our design, we used a syngas cooler to recovery heat to generate electricity other than to use a water quench to recovery chemicals. From Table 29 we can see a large part of energy (54.4 MWe) was recovered from raw syngas. Table 29: Power from Syngas cooled steam. Flow Rate of steam kg/s 159.3 Power MWe 54.37 2. Recovery Energy from Biofuel Synthesis Waist Steam In F-T diesel synthesis process, a large flow rate of waist steam was generated. We recovered this part of energy by sending the steam to HRSG to be superheated and then sending it to the steam turbine to generate electricity. This steam could generate 22 MWe electricity. Table 30: Power from F-T diesel synthesis waist steam. Flow Rate of steam kg/s 126.8 Power MWe 21.77 3. Recovery Heat from HRSG Exhaust Gas Exhaust gas from HRSG still was in high temperature (210°C). We designed to recover this heat to saturate water in a water heat exchanger. The saturated water then was sent to the syngas cooler to generate steams. This part of heat recovery increased the system efficiency. 64
Figure 25showed the detailed energy and mass flow in the water heater. The recovered energy from HRSG exhaust gas was shown in Table 31. Figure 25: Energy and mass flow in the water heater. Table 31: The recovered energy of from HRSG exhaust gas to saturate H2O in the Water Heater. Temperature °C 120.6 Pressure bar 1.01 Flow Rate kg/s 257.02 cp a kJ/kgK 1.901 Energy H2O absorbed MW 46.71 4. Recovery Energy from HRSG A HRSG was designed to recover heat from gas turbine exhaust gas. High temperature (610°C) exhaust gas superheated steam from biofuel synthesis or from the deaerator for steam turbine to increase power generation. From Table 32 we can see, 21 MWe power can be recovered from HRSG. Table 32: Power generated in the steam turbine with energy recovered from HRSG. Power from MP Steam Flow Rate kg/s 6 Power MWe 1.94 Power from LP Steam Flow Rate kg/s 57 Power MWe 19.45 Power from HRSG recovered heat MWe 21.4 65
Page 1 and 2:
Novel Design of an Integrated Pulp
Page 3 and 4:
Table of Contents List of Figures .
Page 5 and 6:
List of Figures Figure 1: Price of
Page 7 and 8:
1 Introduction The global transport
Page 9 and 10:
2 Background 2.1 Pulp Mill Backgrou
Page 11 and 12:
2.1.2.2 Chemical Pulping The most c
Page 13 and 14: sodium sulfide and sodium carbonate
Page 15 and 16: process described in the section on
Page 17 and 18: 2.2.1 Low-Temperature Black Liquor
Page 19 and 20: Figure 2: Chemrec gasification proc
Page 21 and 22: Table 3: Average syngas composition
Page 23 and 24: DME than that could be obtained fro
Page 25 and 26: U.S. Patent[58] and European Patent
Page 27 and 28: Figure 4: Topsøe gas phase technol
Page 29 and 30: DME Workshop, Japan (Sept. 7, 2000)
Page 31 and 32: 2.4.1. Fischer-Tropsch Reactors The
Page 33 and 34: kpH 2 pCO Cobalt rate = 2 (2.4.1) (
Page 35 and 36: invention of Fischer-Tropsch in the
Page 37 and 38: Table 7: hydrocarbons and associate
Page 39 and 40: 3 Process Design 3.1 Pulp Mill 3.1.
Page 41 and 42: carbonate is fired in a lime kiln t
Page 43 and 44: lost and the pulp that provides tha
Page 45 and 46: Table 16: General operating paramet
Page 47 and 48: Table 19: Ash analysis of Pittsburg
Page 49 and 50: Table 22: Experimental syngas compo
Page 51 and 52: 3.2.5 Process Options and Flexibili
Page 53 and 54: Nitrogen compounds Nitrogen from th
Page 55 and 56: 3.3.2.3 Reactors A single-step gas
Page 57 and 58: Table 27: FT-diesel fuel synthesis
Page 59 and 60: 3.5.2 Power Generation Process Desi
Page 61 and 62: Figure 21: Schematic of biorefinery
Page 63: ar) reacts with the fuel in the com
Page 67 and 68: 4. Design Summary The DME design an
Page 69 and 70: Figure 27: Mass and energy flow of
Page 71 and 72: References 1. Åhman, M., G. Modig,
Page 73 and 74: 42. R.A. Peascoe, J.R.K., C.R. Hubb
Page 75 and 76: PerformanceSimulation. 2006, Prince
Page 77 and 78: Appendix Appendix A MP Steam Demand
Page 79 and 80: Appendix B: Composite Fuel Blend to
Page 81 and 82: DME Density = 0.67 kg/L (at 20 °C)
Page 83 and 84: Air Separation Unit Requirements Ba
Page 85 and 86: Purge gas: CO conversion is 60%, 40
Page 87 and 88: Appendix D: FTD Synthesis Two diffe
Page 89 and 90: Table D.3: The hydrocarbon product
Page 91 and 92: Figure D.3 Mass and energy balance
Page 93 and 94: Table D.3 Mass and energy balance o
Page 95 and 96: Appendix E: Heat and Power Generati
Page 97 and 98: Energy H2O absorbed MW 46.71 Using
Page 99 and 100: Combustion 2CO+O2→ 2CO2 + 566 kJ/
Page 101 and 102: Specific Heat (cp) b kJ/kgK 1.072 E
Page 103 and 104: Specific Heat of Steam (cp) kJ/kgK
Page 105: Appendix F: Concept Map 105
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