1. Introduction - Firenze University Press

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Abstract: PROCEEDINGS OF ECOS 2012 - THE 25 TH INTERNATIONAL CONFERENCE ON EFFICIENCY, COST, OPTIMIZATION, SIMULATION AND ENVIRONMENTAL IMPACT OF ENERGY SYSTEMS JUNE 26-29, 2012, PERUGIA, ITALY Method of increasing the efficiency of a supercritical lignite-fired oxy-type fluidized bed boiler and high-temperature three - end membrane for air separation Janusz Kotowicz a , Adrian Balicki a a Institute of Power Engineering and Turbomachinery, Silesian University of Technology, ul. Konarskiego 18 44-100 Gliwice, Poland, adrian.balicki@polsl.pl In this paper a thermodynamic analysis of a supercritical power plant supplied with lignite was made. The power plant consists of: a steam cycle at constant power of 600 MW, live steam parameters at 600 °C/29 MPa and reheated steam parameters at 620 °C/5 MPa; supercritical OXY type circulating fluidized bed boiler and air separation unit. An air separation unit is based on a three – end type high temperature membrane. Models of the steam cycle, circulating fluidized bed boiler and air separation unit were built using a commercial computer program GateCycle and inhouse codes. After the integration of the listed above models, CFB boiler thermal efficiency as a function of the oxygen recovery ratio in the high temperature membrane for the variant without and with fuel drying were determined. The calculated thermal efficiency for the variant with fuel drying increases from 76% to 87% with increasing oxygen recovery ratio from 0.45 to 0.9. Keywords: Thermodynamic analysis, Supercritical oxy-fuel boiler, High temperature membranes, Oxy-combustion, Lignite drying 1. Introduction The necessity of meeting the standards of flue gas emissions, introduced by both, EU and national legislators, requires the continuous development of the technologies, which allow for maximum limitation of the greenhouse gases emission. The group of these technologies includes oxy– combustion technology, which, thanks to an almost complete elimination of nitrogen from the process, substantially limits the flue gas stream generated by the power unit [1]. For uninterrupted operation of the OXY type boiler it is necessary to provide a constant stream of oxidizer with the highest possible oxygen content, which mixed with a stream of recirculated exhaust gas as an oxidizing is mixture fed to the combustion chamber. The production of the technical oxygen with the use of both currently available on an industrial scale cryogenic technology and considered alternative technologies, is associated with the significant power consumption of the process, and thus also with a decrease of the efficiency of the block [2]. For boilers fed with lignite, just like in classical solutions, a possible way to improve the efficiency of electricity generation is to pre-dry the fuel prior to the injection into the combustion chamber. The presence of large amounts of water in the fuel reduces the lower heating value, enforces necessity to provide greater fuel mass flow to the boiler and, which is particularly important in systems with wet type recirculation, increases the probability of condensation of moisture from the flue gases. The drying process requires the delivery of large quantities of the drying medium, of which a function is to raise the temperature and the evaporation of the greatest possible amount of moisture from the fuel. In the classical solutions as a drying medium hot air or exhaust gases leaving the boiler is used. In OXY type 197
systems for fuel drying waste stream of a mixture of nitrogen and oxygen from the air separation unit can be used. 2. Assumptions A model of a supercritical boiler with circulating fluidized bed working in oxy - combustion technology was built using commercially available computer program GateCycle and in-house codes. Scheme of the model built (with ideological scheme of steam cycle) is shown in Figure 1. Fig. 1. Scheme of the CFB boiler integrated with lignite dryer, steam cycle, ASU and CCS installations At the stage of adopting assumption for its construction it was decided to use provided by the GateCycle program the fluidized bed boiler block, which consists of: furnace chamber (AC), evaporator (EVAP) and last sections of the live steam superheater (PP II) and reheated steam superheater (PW II). In the direction of flue gas flow this block ends with particle separator (cyclone). After the cyclone gas/gas type heat exchanger (PPO), in which air from ASU installation is heated to the temperature of 850°C, was placed. Subsequently following exchangers were placed: live steam superheater (PP I), reheated steam superheater (PW I), economizer (ECO), recirculated 198
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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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Page 175 and 176: Figure 2. Sketch of the suggested P
Page 177 and 178: a b Figure 5. a) Exergy balance of
Page 179 and 180: The basis of comparison of each met
Page 181 and 182: Figure 7a. Impact of S/CATR on PCU
Page 183 and 184: However, more energy duty is requir
Page 185 and 186: Abstract: PROCEEDINGS OF ECOS 2012
Page 187 and 188: 3.1. JACOBIAN-ASPEN Interface ASPEN
Page 189 and 190: Fig. 3. Triple Pressure Bottoming S
Page 191 and 192: As seen from Table 1, the mass flow
Page 193 and 194: 4. Conclusion Fig. 5. Partial Emiss
Page 195 and 196: [19] Yantovski E., Shokotov M., Sho
Page 197 and 198: investigation and the developing of
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Page 201 and 202: hydrogen combustion technology at d
Page 203 and 204: eversibility of a pre-treated synth
Page 205 and 206: Fig. 1. TG curves collected for spe
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Page 211 and 212: CO2 capture capacity up to 150 th c
Page 213 and 214: the way for biogas utilisation is t
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Page 217 and 218: 4. Pilot plant tests In order to de
Page 219 and 220: Concerning the absorption reaction,
Page 221 and 222: with Regeneration (AwR), consists i
Page 223: [25] Aspen Plus 2004.1. Cambridge,
Page 227 and 228: heated in a heat exchanger placed i
Page 229 and 230: Fig. 2. Lower heating value of fuel
Page 231 and 232: Acknowledgements The results presen
Page 233 and 234: large amount of CO2 [1,5-7]. APCr a
Page 235 and 236: N 1 i ( x x i n 1 m ) 2.3. Carbon
Page 237 and 238: DTA analysis of the untreated APCrs
Page 239 and 240: Table 4. Relative Error (%) of the
Page 241 and 242: CaO HCl CaCl H O 193kJ / mol (
Page 243 and 244: [1] M. Fernández Bertos, S.J.R. Si
Page 245 and 246: Abstract: PROCEEDINGS OF ECOS 2012
Page 247 and 248: 2. Process development 2.1. Backgro
Page 249 and 250: to dissolve the chloride salts prec
Page 251 and 252: The remaining 25% (5 ml/min) of the
Page 253 and 254: Table 6. Experimental conversions o
Page 255 and 256: p p 1 1. 5 p H 1 1. 5 2O p mi
Page 257 and 258: Calculating from the Aspen Plus mod
Page 259 and 260: [11] Mattila, H.-P., Experimental s
Page 261 and 262: Mg2SiO4(s) + 2CO2(g) →2MgCO3(s) +
Page 263 and 264: (Mg/Fe) of the mineral rock, Mg-sil
Page 265 and 266: Figure 2. Effect of Mg/Fe ratio of
Page 267 and 268: Figure 4 shows that an increase in
Page 269 and 270: Figure 5. Process flow diagram of M
Page 271 and 272: 2. Only cold utility is needed belo
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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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Te 1000 mp era 900 tur 800 e [°C 7
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Application of the approach led to
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The advantage of dynamic models is
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e equal at both time intervals and
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2.5. Selecting the number of TSs Se
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A) Time Slices for solar thermal en
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The first step of procedure is to p
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cTSs demand TS solar TSs 0 2 4 6 8
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In the presented paper a framework
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[5] Erdil E, Ilkan M, Egelioglu F.
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district energy network simulation
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were decreased by 10°C.All scenari
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Site 3 Heat sources Heat load Site
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3.2.2. Input data and assumptions A
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Fig.7 shows the operation forecast
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[13] TERMIS Operation User Guide, 7
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Polygeneration is a term used to de
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The increase in energy utilization
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are available for an entire year, 8
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6. Extensions to core methodology 6
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thermal storage and possible suppor
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laterites. Ore Geology Reviews, v.
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gasification [15], hybrid biomass g
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the second reactor. In this unit, s
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The variables effect was evaluated
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atio, as well as the shift-syngas f
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Fig. 4. Effect of operating tempera
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SDG has slight effect on the syngas
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[26.] Castle WF. Air separation and
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1. Introduction - Firenze University Press

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