1. Introduction - Firenze University Press

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where the thermodynamic integration of processes leads inherently to higher effectiveness, fuel saving and therefore decrease of CO2 emission. Combining the availability of a moderate-temperature waste heat at the CO2 removal facility with inherently high effectiveness of the coal-fired CHP plant, the idea for the CHP system equipped with CCS unit and utilizing waste energy for district heat production has been proposed and analysed within the current paper. It was expected, that the high-level integration of power cycle with CO2 removal unit and district water heat exchangers will the partial recovery of CCS energy expenses make possible. Within the current paper two different CHP plants incorporating presented idea have been proposed and investigated. First is the classical Rankine-based steam unit equipped with back-pressure steam turbine, circulated fluidized-bed boiler and CO2 removal unit based on chemical absorption in monethanolamine. Second plant configuration is based on IGCC structure equipped with precombustion CO2 removal based on physical absorption in Selexol. Both plants have been scaled to the same rated district heat production (110 MWt). The idea for rather small CHP units equipped with CO2 removal and waste heat recovery is relatively new. There is a lot of literature references for CHP systems (non CCS) based on CFB boilers, as well as, for large coal-fired power units equipped with post-combustion CCS. The problem of waste heat recovery from the chemical CO2 absorption units is discussed e.g. in [1] In case of IGCC CHP system, described in literature installations use biomass mostly. Experience gained in IGCC CHP plants based on biomass gasification may be however transferred into similar plants based on coal. Several IGCC CHP plants do exist, however usually biomass or wastes are gasified, there is no plant which uses hard coal as a main feedstock. The SVZ plant in Schwarze Pumpe is one of such installations where coal and municipal wastes mix is gasified in BGL (British Gas and Lurgi) gasifier [2]. Installation produces electricity and methanol. This installation was however unprofitable, which caused that in year 2007 has been closed [2]. Another example of IGCC CHP plant is installation in Varnamo in Sweden. This biomass-based unit reaches 6MWe electric and 9MWth thermal power, while the energy efficiency in cogeneration mode is 83% [3]. Plant in Varnamo was operating since 1996 till 2000, then it was closed for the same reason as SVZ plant [3]. Plant which uses lignite as a main feedstock for IGCC has been built in Versova (Czech Republic) [4]. There are 26 Lurgi and 1 Siemens gasifier in operation. Electricity and liquid fuels are the main products of this installation, however hot flue gas is used for district heat production [4]. In all recognized IGGC CHP installations district heat is produced in conventionally as for combined cycles – using flue gas from the heat recovery steam generator (HRSG) exhaust or steam turbine extraction. 2. Case studies Two case studies of CCS-integrated CHP units have been analyzed: IGCC CHP plant with waste heat recovery equipped with Selexol-based CO2 absorption, CFB CHP plant with waste heat recovery equipped with tap-backpressure steam turbine and MEA-based CO2 absorption. For comparison purposes the same fuel parameters have been used for both analysed systems. Fuel composition has been presented in Table 1. Table 1. Fuel composition Coal parameters (as received) c, carbon - 0,5263 h, hydrogen - 0,0343 o, oxygen - 0,1102 n, nitrogen - 0,0075 s, sulphur - 0,0104 117
moisture - 0,2237 ash - 0,0876 LHV MJ/kg 20,16 2.1 IGCC plant IGCC plants are usually designed as electricity or chemicals production plants, however they have a high potential for district heat production. Present IGCC units (especially with CO2 capture) give an opportunity for recovering waste heat at levels suitable for district heat production as well as for using classical heat sources e.g. tap-steam turbine or outlet of HRSG. Proposed IGCC CHP plant configuration is schematically presented in Fig.1. The system is based on that presented in [5] which has been optimized and redesigned towards IGCC CHP plant. It is composed of cryogenic air separation unit (ASU), dry-feed gasifier with syngas cooler, water gas shift reactors (WGSR), acid gas removal (AGR) unit and finally the combined cycle. Fig. 1. Concept of IGCC CHP plant The entrained flow dry-feed gasifier has been chosen for syngas production. Its operating pressure has been set to 4,238 MPa. The temperature of the syngas leaving the reactor reaches 1639 o C. The syngas is cooled down primarily by its partial recirculation and then by the production of high pressure steam in a radiant/convection heat exchanger. The temperature of the syngas leaving the cooler and entering the scrubber is equal to 335C. The gasification reactor consumes oxygen of 95% purity. The coal feeding system is based on ASU nitrogen. The syngas treating and conditioning line is composed of an inter-cooled WGSR reactor. The syngas temperature after the first WGSR reactor has been assumed to 460C while behind the second one to 360C. The heat rejected from the syngas during the conditioning processes is recovered to the steam cycle and for district heat production. The AGR unit is based on a two-stage Selexol process. The syngas stream leaving the second WGSR is cooled down, dehydrated and supplied to the first stage of AGR unit, where 99% of H2S is stripped. The separated H2S is then sent to the Claus plant for 118
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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
Page 94 and 95: methane slip contributes to 13% of
Page 96 and 97: As can be seen in Fig. 5 the impact
Page 98 and 99: References [1] Eurobserv’er, The
Page 100 and 101: PROCEEDINGS OF ECOS 2012 - THE 25 T
Page 102 and 103: in which CO2 is separated from H2,
Page 104 and 105: dimensions of water droplets and wa
Page 106 and 107: Temperature (°C) 8 7 6 5 4 3 2 1 0
Page 108 and 109: 4. Conclusions In the present paper
Page 110 and 111: Abstract: PROCEEDINGS OF ECOS 2012
Page 112 and 113: penalty, but without separate captu
Page 114 and 115: 0.5 - 0.7 kg/kg, resulting typicall
Page 116 and 117: 3.3 - Utilising waste heat All exis
Page 118 and 119: 4.5 - Suomusjärvi olivine deposits
Page 120 and 121: material will change from a few % t
Page 122 and 123: Fig. 5 Schematic diagram of the PFB
Page 124 and 125: 8. Combined SO2 capture and CO2 min
Page 126 and 127: Fig. 10 Carbonate- (left) and sulph
Page 128 and 129: [13] Ekdahl, E., Idman, H. Statemen
Page 132 and 133: HEAT Fig. 1. Scheme and main reacti
Page 134: (raw) materials pre-heating and AS
Page 137 and 138: Fig 3- Aspen Plus® model 110
Page 139 and 140: Table 4. Elemental and XRD analysis
Page 141 and 142: the ÅA CSM route. The content of M
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Page 147 and 148: 2.2 CFB plant For the current momen
Page 149 and 150: The CO2 emission factor which indic
Page 151 and 152: The CO2 emission factor calculated
Page 153 and 154: Appendix A Fig A.1. Simulation mode
Page 155 and 156: (b) Fig. A.2. Simulation model of C
Page 157 and 158: Table A.1. Calculated parameters at
Page 159 and 160: References [1] Pfaff I., Oexmann J.
Page 161 and 162: with a CC installation could be avo
Page 163 and 164: 2.3. Basic CHP plant indices. The b
Page 165 and 166: 3. Off-design calculations The main
Page 167 and 168: Fig. 6. CHP plant efficiency Fig. 7
Page 169 and 170: amount of steam delivered to the he
Page 171 and 172: [5] Lukowicz H., Mroncz M.: Analysi
Page 173 and 174: water removal is feasible by coolin
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 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
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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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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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