1. Introduction - Firenze University Press

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The Soave-Redlich-Kwong equation of state with Kabali-Danner mixing rules (SRKKB) was selected to calculate all thermodynamic properties for the conventional components in the overall process. Additionally, the HCOALGEN and DCOALIGT models were used to calculate enthalpy and density for coal and ash (non-conventional components) [14]. 3.2. Chemical Reactions Gasification reactions occur above 873 K; at this temperature or higher, the kinetic barrier is minimized and reactor products are found around equilibrium. Therefore, in the simulation, a free kinetics model was implemented [33]. In this model, the equilibrium approach was employed by neglecting the hydrodynamic complexity of the gasifier. Gasification products are estimated employing the RGibbs model which uses Gibbs free energy minimization to calculate the chemical equilibrium of a list of conventional components. The gasification products are taken from the most important coal gasification reactions (Table 4) [18]. As RGibbs only estimate chemical equilibrium of conventional compounds, it is necessary to decompound solid coal (a nonconventional compound) on its constituting components. This is done by using the RYield model and specifying the yield distribution according to the Guaduas coal ultimate analysis. By this approach, satisfactory results have been obtained for many researchers from gasification simulation using Aspen Plus ® [14, 16, 34, 35]. The HTS and LTS reactors are simulated using the REquil model. The WGS reaction (R4) and COS hydrolysis (R14) are obtained specifying the stoichiometric reactions [4]. Table 4. Main process reactions Reaction Reaction name 4. Sensitivity Analysis 345 Heat of reaction (kJ mol -1 ) Carbon combustion -393 R1 Carbon combustion -221 R2 Boudouard +173 R3 Steam gasification +131 R4 Water gas Shift -412 R5 Steam reforming - 206 R6 , Methanation -165 R7 Sulfur combustion - 297 R8 H2S formation -207 R9 Reaction number CS2 formation +115 R10 COS formation +63 R11 NH3 formation -46 R12 NO2 formation +66 R13 COS hydrolysis -34 R14 Sensitivity analysis was performed with the aim to analyze and optimize overall operating conditions in the process. The chosen variables were: 1) O2 to coal mass ratio, 2) mass solid concentration in coal slurry, 3) LTS reactor operating temperature, and 4) steam to dry gas molar ratio (SDG) in the WGS process.
The variables effect was evaluated over the next key process parameters: 1) syngas molar composition upstream and downstream the WGS process, 2) overall CO conversion in the WGS reactors, 3) lower heating value (LHV) of H2 rich-syngas, and 4) thermal efficiency ( ). 4.<strong>1.</strong> Thermal efficiency As the best performance, which is also the most economic option, is sought; this discussion starts showing the results obtained during the sensitivity analysis for thermal efficiency ( ). This is an indicator of the overall process performance [14]. Thermal efficiency was calculated considering the hydrogen-rich syngas output energy divided by the thermal energy of the coal used as raw material and the energy requirements for auxiliary equipment (ASU, Rectisol, etc) as follows: Table 5. Variables effect on and H2-rich syngas LHV Variable TE, % LHV, MJ kg -1 LHV, MJ Nm -3 H2 molar fraction in H2rich syngas O2 to carbon ratio † 0,160 34,1 55,5 20,9 0,561 0,320 42,2 69,0 15,1 0,806 0,480 52,0 79,8 13,0 0,895 0,640 62,6 83,4 12,0 0,922 0,800 60,1 92,7 10,8 0,977 0,960 54,5 97,3 10,7 0,983 Coal slurry concentration (% w/w) ‡ 86,21 61,3 61,8 10,8 0,926 75,47 60,4 87,0 10,8 0,971 65,01 59,9 95,1 10,8 0,979 56,34 59,2 97,0 11,0 0,974 50,00 58,4 93,4 11,5 0,958 LTS reactor temperature (K)** 453,15 59,5 99,3 10,7 0,983 473,15 59,9 95,1 10,8 0,979 473,25 59,9 95,0 10,8 0,979 498,15 60,4 88,6 10,8 0,971 523,15 61,5 81,5 10,8 0,962 SDG gas molar ratio in WGS †† 0,694 59.9 95,1 10,8 0,979 0,972 58.6 102,5 10,8 0,986 1,768 55.3 106,3 10,8 0,989 2,564 52.4 107,3 10,8 0,990 3,360 49.8 107,7 10,8 0,990 3,917 48.2 107,9 10,8 0,991 † Solid concentration in coal slurry: 0.65, WGS process SDG : 0.59, LTS reactor operating temperature: 473 K and HTS reactor operating temperature: 623 K. ‡ O2 to coal ratio: 0.8, WGS process SDG : 0.59, LTS reactor operating temperature: 473 K and HTS reactor operating temperature: 623 K as fixed variables. ** O2 to coal ratio: 0.8, solid concentration in coal slurry: 0.65, WGS process SDG : 0.59, and HTS reactor operating temperature: 623 K as fixed variables. 346 (1)
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Proceedings e report 90
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ECOS 2012 : the 25 th International
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Advisory Committee (Track Organizer
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The 25 th ECOS Conference 1987-2012
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VOLUME VI CONTENT VI. 1 CARBON CAPT
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-----------------------------------
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» Personal transportation energy c
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» Excess enthalpies of second gene
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VOLUME IV IV . 1 - FLUID DYNAMICS A
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» Exergy analysis and genetic algo
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» Optimal lighting control strateg
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» Stability and limit cycles in an
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PROCEEDINGS OF ECOS 2012 - THE 25 T
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Fig. 2. The exergy destruction of M
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ineffectiveness of the catalyst, in
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[ P EXmth EX SNG] ESR F where EXm
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Fuel inputkW 728221 203771 237719 3
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Not only at desined Rc (the ratio o
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4. DISCUSSION The graphic exergy an
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Figure 9(a) illustrates the energy
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Engineering Technical Conferences &
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generally there are four kinds of m
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However, even under the off-design
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Fig. 3. 600MW supercritical coal-fi
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CO2 rich loading(molCO2/molMEA) 0.4
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Net efficiency (%) 40.28 30.29 26.4
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Fig. 11. Schematic diagram of heat
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28.67%. In addition, through heat i
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Applied Thermal Engineering 2010;30
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Abstract: PROCEEDINGS OF ECOS 2012
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Fig. 1. Solution diagram of „four
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K ~ K 1 eK 1a p K 1a iK mK
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Oxygen recovery rate, % 105 95 85 7
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Calculated optimal compressor press
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The net amount of the flue gas leav
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Figure 3. Idea for lignite drying b
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Energy efficiency, % 34,00 33,00 32
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points efficiency increase related
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Figure A1b. Thermoflex flow sheet o
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Figure A3a. Thermoflex flow sheet o
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Figure A4. Thermoflex flow sheet of
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2.1. Life Cycle Assessment 2.1.1. G
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these factors. A sensitivity analys
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methane slip contributes to 13% of
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As can be seen in Fig. 5 the impact
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References [1] Eurobserv’er, The
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in which CO2 is separated from H2,
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dimensions of water droplets and wa
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Temperature (°C) 8 7 6 5 4 3 2 1 0
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4. Conclusions In the present paper
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penalty, but without separate captu
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0.5 - 0.7 kg/kg, resulting typicall
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3.3 - Utilising waste heat All exis
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4.5 - Suomusjärvi olivine deposits
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material will change from a few % t
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Fig. 5 Schematic diagram of the PFB
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8. Combined SO2 capture and CO2 min
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Fig. 10 Carbonate- (left) and sulph
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[13] Ekdahl, E., Idman, H. Statemen
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HEAT Fig. 1. Scheme and main reacti
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(raw) materials pre-heating and AS
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Fig 3- Aspen Plus® model 110
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Table 4. Elemental and XRD analysis
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the ÅA CSM route. The content of M
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moisture - 0,2237 ash - 0,0876 LHV
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2.2 CFB plant For the current momen
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The CO2 emission factor which indic
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The CO2 emission factor calculated
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Appendix A Fig A.1. Simulation mode
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(b) Fig. A.2. Simulation model of C
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Table A.1. Calculated parameters at
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References [1] Pfaff I., Oexmann J.
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with a CC installation could be avo
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2.3. Basic CHP plant indices. The b
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3. Off-design calculations The main
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Fig. 6. CHP plant efficiency Fig. 7
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amount of steam delivered to the he
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[5] Lukowicz H., Mroncz M.: Analysi
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water removal is feasible by coolin
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Figure 2. Sketch of the suggested P
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a b Figure 5. a) Exergy balance of
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The basis of comparison of each met
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Figure 7a. Impact of S/CATR on PCU
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However, more energy duty is requir
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3.1. JACOBIAN-ASPEN Interface ASPEN
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Fig. 3. Triple Pressure Bottoming S
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As seen from Table 1, the mass flow
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4. Conclusion Fig. 5. Partial Emiss
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[19] Yantovski E., Shokotov M., Sho
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investigation and the developing of
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University of L’Aquila and German
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hydrogen combustion technology at d
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eversibility of a pre-treated synth
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Fig. 1. TG curves collected for spe
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(see Fig 5). Carbon dioxide uptake
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period is reduced to the first 15 c
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CO2 capture capacity up to 150 th c
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the way for biogas utilisation is t
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projectand is described in the foll
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4. Pilot plant tests In order to de
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Concerning the absorption reaction,
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with Regeneration (AwR), consists i
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[25] Aspen Plus 2004.1. Cambridge,
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systems for fuel drying waste strea
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heated in a heat exchanger placed i
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Fig. 2. Lower heating value of fuel
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Acknowledgements The results presen
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large amount of CO2 [1,5-7]. APCr a
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N 1 i ( x x i n 1 m ) 2.3. Carbon
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DTA analysis of the untreated APCrs
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Table 4. Relative Error (%) of the
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CaO HCl CaCl H O 193kJ / mol (
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[1] M. Fernández Bertos, S.J.R. Si
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2. Process development 2.1. Backgro
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to dissolve the chloride salts prec
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The remaining 25% (5 ml/min) of the
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Table 6. Experimental conversions o
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p p 1 1. 5 p H 1 1. 5 2O p mi
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Calculating from the Aspen Plus mod
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[11] Mattila, H.-P., Experimental s
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Mg2SiO4(s) + 2CO2(g) →2MgCO3(s) +
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(Mg/Fe) of the mineral rock, Mg-sil
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Figure 2. Effect of Mg/Fe ratio of
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Figure 4 shows that an increase in
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Figure 5. Process flow diagram of M
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2. Only cold utility is needed belo
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extraction process at 400 °C (~ 62
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Table A2. Extraction equations and
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[13] Teir S, Kuusik R, Fogelholm CJ
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In the area of coal technologies al
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Tabel 1. Characteristics quantities
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N m eT 4a ~ T cp T4a 1 ( K
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Auxiliary power rate of ASU, % 40 4
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[8] Buhre B.J.P., Elliott L.K., She
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1.1 - Cement Manufacturing The ceme
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2. Numerical model The purpose of t
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-0.309x15.77x2 2.085x3 240x4 12.53x
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Table 4 - Results of the optimizati
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1. Define the studied system (in th
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cycle) or a lignin extraction plant
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limiting factor for the maximum siz
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Table 5. Key data for the four ener
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Global CO 2 emissions [ktonnes/yr]
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for biofuels and the investment cos
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The possibility to capture CO2 from
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[17] Berglin N, Andersson L. Proces
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Therefore NL Agency (an agency of t
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2.2.2. Pinch analysis Pinch analysi
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3. Case study 3.1. Plant and proces
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Page 361 and 362: 6. Extensions to core methodology 6
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Page 367 and 368: Abstract: PROCEEDINGS OF ECOS 2012
Page 369 and 370: gasification [15], hybrid biomass g
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1. Introduction - Firenze University Press

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