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Home My WebLink AboutThermal Energy Integrated Power Systems (TIPS) AK Coal 2008=<DhermoEnergyCc4 Analysis of ThermoEnergy Integrated Power Systems in New Power Facilities Using Alaska Coals Interim Report August 2008 Submitted by Alex Fassbender,Robert Henry,and Li Tao ThermoEnergy Corporation 5 Kane Industrial Drive Hudson,MA 01749 This work was sponsored by The Alaska Energy Authority i Interim Draft Report Federal Grant Number EM-833233301-0 August 22,2008 Acknowledgements ThermoEnergy gratefully acknowledges the support and assistance of the following organizations. U.S.Environmental Protection Agency Alaska Energy Authority CANMET U.S.Department of Energy University of Nevada Reno Babcock Power ii Interim Draft Report Federal Grant Number EM-833233301-0 August 22,2008 Contents Project Executive SUMMArY..........cccccsssesscesscsssesssessesssesssessssssceseesseeseesssesseesssecsssececsesenesseeeusesnseseens 9 Part 1:Summary of TIPS Modeling for AEA Project .........ccccccsccscessessessessesseesseseeseeseeseseessessenes 10 Usibelli Coal TIPS Modeling 00...eeccsssseesseeceescssecscescssenecssesssessesesssssassscssesseseesseeesssseaeeees 10 Modeling of a CO2 Power Cycle Combined with Rankine Cycle ......eccceessscceseesessseseesseneees 24 Heat Transfer Analysis Using Aspen TASC+occ eesseseescsecssesseessceseseescecesceseeeseeessaseasenees 24 Liquid Nitrogen Plant .0.......es cssssecsscscseesssssesceeesessceseseeesseeseesseessesesassassceasesssesseeaseesecteteesees 26 Eight Pound Steam Generation 0...cessescessceseesseceeeesecsseasesesesssescecesarssesseessasseeeeeacsansceaenaees 26 Coal to Liquids Plant Using TIPS to Combust Fischer Tropsch Tail Gas........cc ceeseeeseeeeeeeee 26 Heat Integration .......eee eesesessscsecseeseseeecsceseeoesesensececasessesesseeeaesaseneesesenesaeeaceaeeassesesesenesesenees 28 Comparison of TIPS Configuration with Air Fired Boiler Configuration...cesses 28 CONCIUSIONS..........:cssceesessesecescessesceseesseeseessenesscenaesasesevscesecacessssseaeeasenscsdseaeasenseasenevarenssenesssens 30 Part 2:Testing of a Pressurized System to Generate Physical Property Data on Synthetic Exhaust GaS StreaMs .......scessessestsesesensessessecssscseseesssecsseesssescesscseassesssssessensseesssssssssessossscassssseneseneseescensvess 31 Heat Exchanger Unit...eeeeesseecssssssssesssssesssosessecssssssesesssescneseesessssasesseesseasessessensesseneenses 31 Equipment List -.........cccscssescssesssesessecscceesessscesscssessessesssesesssorevsesessessceseeseeasensseusesseaseeneees 32 Experimental Design ..........ccssssesscessecesesesscescescsesssesessessosssseesssecssssasessscsecsssscnessesssserensnesecenes 32 Test Variables ........cccsssscssesecseseescescesessecescsssesccscesessseessesecssoseceesssssessesesessusseaecseasessesseseusegs 33 Practical Experimental Technique ............cceccesecsrcesecesecesecencesneeseeesecencenacenceesesesceseeescesneessenes 33 Experimental Sequence.......ccccescsccscsssssssssssccssssscsessscssevssesecsesssessessreesseensesaessssaessessreseenenes 33 Experimental Procedure .........ccccsssscsssscsssssesssescsssesssseesessesesseseseesesesseseseenesseseanesesserenseseeagenens 33 Data Analysis Method:........cscsssecssssssessesssssessssesessesssesssssesessesessseesesnesensseeenessseeeasasenenenes 34 Dimensionless Analysis for Free COnvection.......ccssssscsssessseeseseeessesesesssesessesenesersrenssenes 36 NOteS ....ccccsscsssesscessesccessscencesneesceesesessesseeseessessssssusesscsssseseseseseseseceseeseeensessecesectensesntenentenseseeey 38 ili Interim Draft Report Federal Grant Number EM-833233301-0 August 22,2008 Heat Transfer Analysis Results SUMMary ..........cccsesceeercesecceseessessscsseeessesssesssnesseseseseeeaees 38 Comparison of Experimental Data with TASC+Model Results.......cccccesscesesesesserserenees 40 Discussion Of Results.......ccessseccecscessecesesevsscseesssscscsesssessessessseseesseesessecssseenessseneseesessnesessesseeses 4] Liquid Vapor Equilibrium...cic eesecseesesessscsessescesscssesessessssssessesseessesssessessecasenseaesesneseseenses 42 Commercial Phase Equilibrium Analyzer...escsscssesesessscsscscesssscesenesssseseseseeeesseneeseens 42 Gas Chromatography ..........ccsccssccscesscessetesceeeeeenesseseeeseesaceeseceseessaessessescssesscssesoeessasessnssnasenee 43 Gas Preparation.........cceccsssessssssssesecesceccsscesecsseseseseseseseeseeseseeesecesecsncsesssesessssessessssesesseeeeenersseee 43 Experimental Design...ceesscsssessessesccsereecssecscsscessesevsesssssessesseasscseusssesesseensscseesecareneeeeennes 44 Thar Unit Procedural Notes .0........cscscssessssscsseseceesseesecesscsecsavsesssesssssasstssssseessresesseeesensseeenes 45 Liquid Vapor Equilibrium Testing Results Summary .........cscecssesescseessssesssseseesssssesenenees 47 Small Vessel Experiment .........cc eccessccssccsseccssceesecessceesneeeceeessesesseseseasesesessesessesesssccsesessesenesesases 52 Data...ccsccssessececcssesecensescesesensteseseeseeesesceaeesesessesseeesseseossessessesssssosacsssessseuseussesseseensusenseusenees 53 NOTES oo.eeceecesccsecssecesesescesscesseseseesaseseccsesensessecssseesesasessssescseessnssssenssesscssessesessesseerscsssnereneseess 55 Appendix A:Usibelli and CTL Modeling Flowsheets and Stream Tables .0.........es eeseseseeeeeeeees 59 A1A:Usibelli Coal Power Plant,No Slurry,Dry Ash Flowsheet ............cesssssseerceereseeeeeeeeees 59 A1B:Usibelli Coal Power Plant,No Slurry,Dry Ash Material Stream Table...eee 60 AIC:Usibelli Coal Power Plant,No Slurry,Dry Ash Heat Stream Table...cece 64 AID:Usibelli Coal Power Plant,No Slurry,Dry Ash Work Stream Table...eeeeereeees 64 AIE:Usibelli Coal Power Plant,No Slurry,Dry Ash Block Input....ccescesessessseseesreenes 65 AIF:Usibelli Coal Power Plant,No Slurry,Dry Ash Design Specs .........c:cscssssessssessssesessenees 73 A1G:Usibelli Coal Power Plant,No Slurry,Dry Ash Block Results Summaries..................77 A2A:Usibelli Coal Power Plant,No Slurry,Slagging Flowsheet ........ccccccsesscssssesesssesssseeese85 A2B:Usibelli Coal Power Plant,No Slurry,Slagging Material Stream Table ...........cccceesee 86 A2C:Usibelli Coal Power Plant,No Slurry,Slagging Heat Stream Table ..........ccessesceeeeseees 93 iv Interim Draft Report Federal Grant Number EM-833233301-0 August 22,2008 A2D:Usibelli Coal Power Plant,No Slurry,Slagging Work Stream Table ........cesessessereees 93 A2E:Usibelli Coal Power Plant,No Slurry,Slagging Block Input ...........cssscssssceteseteeeeeeees 94 A2F:Usibelli Coal Power Plant,No Slurry,Slagging Design Specs..........ccccssescsscssesseseseees 102 A2G:Usibelli Coal Power Plant,No Slurry,Slagging Block Results Summaries ................106 A3A:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Flowsheet..........114 A3B:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Material Stream Table oo...eesesssssscessesscssecesesceseesssaeseesssscnecssessssessessenessessesrensesseussassccassasssesecaeesesecseeneseeseseesees 115 A3C:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Heat Stream Table seesseseecesseseesssesccssessensuceseesseassecsesscesssssecensescesssssucsssesssssaseasesssetessesssasessssessessessscenssaesteaseatssensenses 123 A3D:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Work Stream Table esssessesscnsesssescescesssesscsaesesaceeessessesasenessnseaeessessessesseetssesseesesasesssensssenssesssassssccseaseaseaseatenaeenesseeneees 123 A3E:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Block Input........124 A3F:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Dry Ash Design Specs.....132 A3G:Usibelli Coal Power Plant,50/50 Coal Water Slurry Block Results ...........ccsccsesseeees 136 A4A:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Flowsheet.........145 A4B:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Material Stream Table oc.eeeecseesscesecsesssesesescesevssenesensesevscesevscseaesessscsessscesssessesesssensaesenessesssnssansaessesasenesaseues 146 A4C:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Heat Stream Table esscacscescescensecessesceeceasssescesseassessceacessassceneessasenesacscessenssaeacessssescescenseasenssceeseeesssseseseeeesseneneeasarenses 154 A4D:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Work Stream Table sesaesaeuceuensscnensescessenssaescsasenssassaeasescssecessesseasensuceseeaseasscssceassesesasesseasensscesecsceesecenecssensasanenseessnenees 154 A4E:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Block Input.......155 A4F:Usibelli Coal Power Plant,50/50 Coal Water Slurry Feed,Slagging Design Specs.....163 A4G:Usibelli Coal Power Plant,50/50 Coal Water Slurry,Slagging Block Results............167 ASA:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Flowsheet..........176 ASB:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Material Stream Table ......cccesscsssesscesscsscsscesscesscsscenseenscesnsesseseesesesssessseesavesevsneesesesecesscenecsesesessadssasesusessonsonesonees 177 Vv Interim Draft Report Federal Grant Number F41-833233301-0 August 22,2008 ASC:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Heat Stream Table sesaseacensesacessescessenseasscenecsecaceaseassaesasaceacessecscessessecessessesseasenenesseessesessssessscssessessssasesseasuesesasnesetees 185 ASD:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Work Stream Table sescescucesssseasssesssseasssescsseseseeeeacsescessecsseasssesesessescseessssesssseasacedsssssessessssseeedseceseesesssseusesessusessssenessees 185 ASE:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Block Input........186 ASF:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Dry Ash Design Specs.....194 ASG:Usibelli Coal Power Plant,60/40 Coal Water Slurry,Dry Ash Block Results ............198 A6A:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Flowsheet.........207 A6B:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Material Stream Table oo...cccsescsecscssnessesceecssseeseesscesceecencsasscesceaccescessessesessesaesevssossaesensessssessesscesseasessssessesseseees 208 A6C:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Heat Stream Table seseenesceaeaceneaseceacessscceseacsseacsdsessavassseasscesesssesecaescessssscassacesscessaseassseesassesedsessassossersnssasessaesesearenss 216 A6D:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Work Stream Table sececscesessscesscessssessecescesessseseesesessesevarsceasssessssesesenscesesedsesesenaneesseesecenssceaessuaesesesesensaseeoaseneneeseaseeeees 216 A6E:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Block Input.......217 A6F:Usibelli Coal Power Plant,60/40 Coal Water Slurry Feed,Slagging Design Specs.....225 ATA:CTL with TIPS Flowsheet ..........ccccccsscsscsscseecstceeeecceseceneeeeseceseseesaseneeeassaeeseensseeneesenerees 238 A7B:CTL with TIPS Material Stream Table oo...eeesssessctecsecesetsetesssecseseceesssacessenseneeentes 240 A7C:CTL with TIPS Heat Stream Table...eseeeeseceseseecesseestsesessesecesssssesssssressseseseeees 252 A7D:CTL with TIPS Work Stream Table ..0...cesessesseceescteceeeeeacserseeseeeeeeeeessceseeacenseeeess 254 A7E:CTL with TIPS Block Input soseaenaeesecenecesseeaecsecasscsssensccsscsnscensccasecsseassesnsenaseenserssenteets 255 ATF:CTL with TIPS Design Specs......ccsssccccsssssscsssssessesssscssesscsessessseacenssesseesessesseseeaeeeeeeees 268 Appendix B:Experimental Data .......c.cccsssssssssssssssscssssessesesessssessssesseseesesesesacstsaesteaeseenessseenesees 287 B1A:Heat Exchanger Data,Pure Carbon Dioxide......c.ccccssscsssssessessesceseessesscsnecsseesenesesanens 287 B1B:Heat Exchanger Data,Carbon Dioxide,Argon .......cccccsssssssessessessessesessessessesssecsscessenss 305 Appendix C:Thar Phase Monitor Data ........ccscssscsscsssscssessescescsscscessessecessessessssacsesscsessscsesasseses 489 vi Interim Draft Report Federal Grant Number FE M1-833233301-0 August 22,2008 Appendix D:Small Vessel Experiment Data.........scssscssessesssssessseesesssessressssanesstssseeneessessneesneenes 529 Appendix E:Synthesis,characterization and SO2 oxidation behavior of noble metal loaded (Pt, Pd)on mixed oxide support (Al203-TiO2).........cscesesscsssesscesseessesseesseesseesseesasenecsnecsuesseeeaeeseenees 651 List of Figures Figure 1 Flowsheet Used in Aspen Plus for Steam Cycle Calculations ...........ccccscsseseseseeeseeees 13 Figure 2 Oxygen Compression Layout Used in Aspen PIUS ..........cccccccsssseessesceesessssscsseeneseeereeeees 14 Figure 3 Aspen Plus Layout of Pressurized Oxy-fuel Combustion .........cccccscssseeesestessetseeeeseees 15 Figure 4 Aspen Plus Layout of CO2 Condensation and Pumping ............cccsssscsssssessesseseesseneeeees 15 Figure 5 Effect of Specific Parasitic Power Losses on the Overall Plant Efficiency ................0 23 Figure 6 Block Flow Schematic of the Coal Only CTL Plant ........c.cccecscsssessesseseesssssessesseeseeees 27 Figure 7 Block Flow Schematic of CTL Plant with TIPS ...........cscssssscsscsscsssetsssesssesseseesesseseneeees 28 Figure 8 HX test unit flow diagram ..........eescsssssesseesssescesceessceseseesscseesesssseesseseessasecesseacseesesseenes 31 Figure 9 DataFit 3D Plot of Heat Transfer Coefficient vs.Pressure and Reynolds Number.......39 Figure 10 DataFit 3D Plot of Nusselt Number vs.Reynolds and Prandtl Numbers...............0006 39 Figure 11 Heat Transfer Coefficient vs.Reynolds Number (Experimental vs.TASC+).............40 Figure 12 Heat Transfer Coefficient vs.Pressure (Experimental vs.TASC+).........cscssssesereeenes 4] Figure 13 Phase Monitor Apparatus .0..........cssescssssesesceseeceseesecseesesesecaseseseeeescscserssesevssseassassasnees 44 Figure 14 Summary of Liquid Vapor Equilibrium Test Data (Cloud Point vs.Pressure)............49 Figure 15 Cloud Points and Aspen Dew Points vs.Pressures and CO2 Compositions Based on Peng-Robinson Correlation............ccsesesesesesecsssesscesesesaccssesssesesesesessecssesssesesossesssesesesasesserasenacenseass 50 Figure 16 Bubble Points vs.Pressures and CO2 Compositions Based on Peng-Robinson Correlation .........:csscssscsssessccssscssccecessccnsecssceeeseeeesceeseceeeseeeseseaecscessesesesaesaeeesesesecesevanensaesnensessasonses 51 Figure 17 Small Vessel Experiment Setup 0.0...cccessssesssssscsssscsssssssssssessessssesessssssesseseseeeesseeeseees 52 vii Interim Draft Report Federal Grant Number EM-833233301-0 August 22,2008 List of Tables Table 1 Proximate,Ultimate,and Sulfur Analyses of Usibelli Coal...ccecsseerseteeseeeseeereees 11 Table 2 Oxygen Analysis........ccscscccsscesscsssescesscessescsesesssecscessceeseseneeseeesesensseseeeeeseesaceneeeeseeaneeees 12 Table 3 Comparison Table of Three Slurry Cases and Base Case Using Dry Ash Combustion..19 Table 4 Comparison Table of Three Slurry Cases and Base Case Using Slagging Combustion.20 Table 5 Product Specifications Using Dry Ash Combustion...........cccssseesecseeeeseesceseeeneeaseeseneees 22 Table 6 Product Specifications Using Slagging Combustion ............scsssessssssceseesceneeeereceneteeeetes 22 Table 7 Results from Aspen TASC+Heat Transfer Analysis ..........ccscsssssescsseeesseeseseceseeenseseeacees 25 Table 8 Net Power Calculation for TIPS CTL Plant ..0.ci escseseseeesseeeceeceeceseceeessesesensosessnoes 29 Table 9 Condensing Heat Exchanger Inlet/Outlet Mass FIOWS ..........cscsccsssssesessceerccesceeneeseesneenees 29 Viii Interim Draft Report Federal Grant Number E¥1-833233301-0 August 22,2008 Project Executive Summary The work for this AEA project (Federal Grant #EM-833233301)consisted of both modeling and experimental work focused on investigating a new thermodynamic approach to energy production with carbon capture.Models were generated using Aspen Plus chemical engineering software to calculate heat and mass balances for several ThermoEnergy Integrated Power Systems,(TIPS)configurations.Heat exchange models were developed using Aspen TASC+. While software models are highly precise by their nature,their accuracy is only as good as the correlations and estimates they make for the properties of the streams under study.The purpose of the experimental work was to compare the model generated properties with actual measured values to validate or improve the model.Usibelli coal was used as a basis for modeling systems employing direct coal to electricity with carbon capture as well as systems using the TIPS thermodynamic pathway to combust the tail gas from a Fischer-Tropsch coal-to-liquids plant. The Aspen models were used to develop a knowledge base on the size and operating parameters of the unit operations.The experimental phase of the project included generating high pressure heat transfer data to compare to the model,observing and recording phase changes usinga state- of-the-art phase monitor and gas chromatograph,as well as generating liquid vapor equilibrium liquid composition data using a small vessel experiments.The results to date indicate that the Peng-Robinson liquid-vapor equilibrium correlations for the bubble and dew points of mixtures of carbon dioxide and argon are sufficiently accurate to use as a basis of engineering calculations.The modeling and experimental work on the overall heat transfer coefficient showeda significant deviation.The actual heat transfer coefficients were found to be a factor of 3 to 4 greater then those estimated by Aspen TASC+.This is a significant finding as it leads to the realization that the overall heat transfer coefficient in a pressurized oxy-fuel system may be 30 to 35 times greater than what can be achieved at atmospheric pressure.Additional work conducted by the University of Nevada,Reno (UNR)focused on investigations on catalytic conversion of SO to SO3.Early indications are that this conversion is achievable under the conditions expected in a TIPS system. 9 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Part 1:Summary of TIPS Modeling for AEA Project The following is a summary of the ThermoEnergy Integrated Power System,TIPS,modeling that has been completed for the AEA Federal Grant #EM-833233301-0. Usibelli Coal TIPS Modeling MODELING OF PRESSURIZED OXY-FUEL FOR RECOVERY OF LATENT HEAT AND CARBON CAPTURE USING USIBELLI COAL SUMMARY A detailed flow sheet of the ThermoEnergy Integrated Power System (TIPS),a pressurized oxy- fuel plant fueled by Usibelli Coal,was prepared with 4 different injection methods.These injection methods were modeled using both dry ash and slagging combustion.The base case for dry ash combustion used no slurry to inject the coal and provided a point of comparison for the more realistic cases that used a coal slurry feed.The second case used a 50/50 coal/water slurry. Since Usibelli Coal already has 26%moisture,enough water to bring the total moisture content to 50%was added to the feed.The water slurry caused a 3.4%drop in efficiency from the base case due to the inability to capture as much of the latent heat of vaporization in the flue gas.The third case used a 60/40 coal/water slurry.Since this was only 40%total water in the slurry,there was only a 1.5%drop in efficiency from the base case.The final case used an alternative injection method which was more effective than using the 50%water slurry.The drop in total efficiency using this method was 1.9%.Slagging combustion was more efficient due to a higher furnace outlet temperature (2300F for dry ash,2700F for slagging).The base case efficiency for slagging was 0.9%higher than the base case for dry ash combustion.The 50%slurry case caused a 1.6%drop,the 60%slurry case resulted in just a 0.1%drop,and the alternate injection case had a 0.7%drop in efficiency. The model for simulation of this plant was developed using ASPEN PLUS 2004.1 software.The results generated from this model demonstrated the effectiveness of TIPS using a low rank,sub- bituminous coal such as the Usibelli Coal from the Healy Mine.The steam cycle used was an ultrasupercritical cycle with inlet steam at 1350F and 4000 psig,with two reheats to 1400F.The most important factor in the efficiency gain for the TIPS is the ability to capture the latent heat of vaporization. 10 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 INTRODUCTION An Aspen Plus simulation was developed to determine the technical performance of a 100 MW TIPS plant using Usibelli Coal with an Ultrasupercritical steam cycle that uses 2 reheats to 1400F.In this simulation,combustion took place at a pressure of 80 bar,which allows for use of the latent heat of vaporization of the flue gas to heat the boiler feed water.This pressure also allows for cooling water to condense the CO}in the product stream and pump this stream to the pipeline quality pressure of 2200 psi.Atmospheric combustion would require a multistage CO2 compressor with refrigeration to produce pipeline quality CO2.Although pressurized oxy-fuel requires oxygen compression for the high combustion pressure,the energy consumption between the oxygen compression and the CO2 pump is less than the energy consumption of CO compression when combusting at ambient pressure.TIPS'ability to capture the latent heat of vaporization of the flue gas increases its advantage over ambient combustion,especially when using high moisture fuels,such as Usibelli Coal. BASELINE CONDITIONS AND ASSUMPTIONS Fuel:Usibelli Coal,a sub-bituminous coal found in the Healy Mine in Alaska,was selected for this study due to a contract ThermoEnergy has with the Alaska Energy Authority (AEA).Table 1 shows the proximate analysis,ultimate analysis,and sulfur analysis used in the ASPEN PLUS model.The high moisture content and low sulfur content make Usibelli Coal a particularly attractive fuel for the TIPS process.The T259 temperature of the ash,or the temperature at which the viscosity is 250 poise where ash slag begins to flow and develop strength,was 2300F.The furnace outlet temperature was set to 2300F so that a dry ash combustor could be employed.The higher heating value of Usibelli Coal is 7,800 Btu/Ib as received and 10,541 Btu/Ib on a dry basis. Table 1 Proximate,Ultimate,and Sulfur Analyses of Usibelli Coal Proximate Analysis Ultimate Analysis Sulfur Analysis Moisture 26 Ash 9 Pyritic 0.432 Ash 9 Carbon 63.25 Sulfate 0.013 Volatile Matter 36 Hydrogen 4.1 Organic 0.185 Fixed Carbon 29 Nitrogen 0.82 HHV,kJ/kg 7,800 Chlorine 0 Sulfur 0.27 Ash 9 Oxygen 22.57 As Received Dry Basis Dry Basis 11 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Oxygen and Ambient Conditions The ambient conditions for this study were: e Coal feed at 59°F, e Ambient Pressure at 14.7 psia, e Cooling water available at 45°F. e Interstage Cooling to 80°F in multistage oxygen compression. e Partial Pressure of Oxygen in the flue gas stream was 0.2 bar.This resulted in an oxygen mole fraction of 0.0025 Table 2 Oxygen Analysis Oxygen from ASU @ 95%purity %by volume Oxygen (O2)95.00 Nitrogen (N2)2.50 Argon (Ar)2.50 Oxygen was assumed to be produced by a cryogenic air separation unit (ASU).The ASU was the biggest factor in plant thermal efficiency loss due to its significant parasitic energy requirement. The parasitic power from the ASU was assumed to be 1 MW per 112 tons per day of oxygen produced. Steam Cycle An ultrasupercritical steam cycle based on NETL's targets was chosen for this study.The conditions of the inlet steam were 1350F and 4000 psig,and there were two reheats to 1400F. The turbine consists of high pressure (HP),intermediate pressure (IP)and low pressure (LP) sections with a reheat between HP and IP and a reheat between IP and LP.The exhaust steam pressure of the LP section was set to 0.5 psia and was total vapor.This resulted in a boiler feed water temperature of 80°F into the BFW pump.For all 4 cases,4,596 tons/day of steam produced 135.7 MW of gross power.The peak steam cycle efficiency was 49.4%.The feed water was heated to 700°F using heat from the condensing heat exchanger.The steam was evaporated and heated to 1350F using convective heat from the boiler.The convective heat was also used for the two reheats to 1400F.Isentropic efficiencies of 0.9,0.9301,and 0.9414 were used for the HP,IP, and LP turbines,respectively.These numbers are consistent with the efficiencies used in NETL's ultrasupercritical steam cycle model.All unit operations in the steam cycle used the NBS/NRC steam table equation of state for thermodynamic calculations of water and steam.Figure 1 shows the layout of the steam cycle used in the simulation. 12 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 a ee Figure 1 Flowsheet Used in Aspen Plus for Steam Cycle Calculations MULTI-STAGE OXYGEN COMPRESSION Unlike atmospheric oxy-fuel,which requires multi-stage CO2 compression,TIPS requires multi- stage oxygen compression pre-combustion to bring oxygen to combustion pressure.In this study, the design pressure for combustion is 80 bar.In order to achieve an oxygen pressure of 80 bar, there were four low pressure compression stages with a pressure ratio of 2.414975 with interstage cooling to 80°F.The low pressure compression brought the pressure from 1.01 to 34.5 bar.Two high pressure compression stages with interstage cooling to 80°F were used to compress from 34.5 to 80 bar.The pressure ratio used for these stages was 1.52316.All unit operations in the multi-stage oxygen compression used the well known Peng-Robinson Equation of State.It was assumed to be a polytropic compressor and the ASME (American Society of Mechanical Engineers)method was used to calculate the process variables.The polytropic efficiencies and mechanical efficiencies were assumed to be 0.86 and 0.98 for each stage, respectively.Figure 2 shows the layout used for calculations for the oxygen compression. 13 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 W. W W-O2MIX ©}W-O2NET |-= STAGE!cool STAGE2 002 STAGES Figure 2 Oxygen Compression Layout Used in Aspen Plus PRESSURIZED OXY-FUEL COMBUSTION Usibelli Coal was input to Aspen Plus as a nonconventional component and the proximate, ultimate,and sulfur analyses from Table 1 were input as component attributes.The higher heating value was input as a pure component parameter on a dry basis.The coal or coal slurry was input into a yield reactor which calculated the amount of energy used to decompose the solid into its components.This unit operated at 80 bar since it is part of the combustor.The component yield included the extra moisture in the cases where there was slurry feed.The decomposed stream entered a stoichiometric reactor where it reacted with the 80 bar,95%oxygen stream. Full combustion was assumed in this unit where all of the carbon was converted to carbon dioxide and all the hydrogen was converted to water.The nitrogen combustion product was specified as NO,and only applied to nitrogen contained in the fuel. The furnace outlet temperature was set to 2300°F,which is the T259 temperature of ash in Usibelli Coal.T259 is the temperature at which the viscosity is 250 poise and slag begins to flow and develop strength.The temperature is set at or below 2300°F to allow for use of a dry ash combustor.This was controlled by the flue gas recycle split.More flue gas was recycled in the base case with no slurry because the liquid mix lowered the furnace outlet temperature.The furnace outlet stream enters a convective heater which is used to balance with the superheater and the two reheats in the steam cycle.This stream enters the condensing heater which is used to balance with the feed water heater in the steam cycle.97%of the water is condensed at 120°F in a flash separator from the flue gas after the condensing heat exchanger.Small amounts of nitrogen,oxygen,sulfur dioxide,carbon dioxide,and argon are condensed in this separator.All of the ash is condensed.The heaters and the separator use the Peng-Robinson equation of state and are assumed to have no pressure drop.The separator is assumed to be an adiabatic flash 14 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 :4 OWa COMBUST SEP |e-fgcasie$Figure 3 Aspen Plus Layout of Pressurized Oxy-fuel Combustion CO)PUMPING After the flash separator,the flue gas stream ranged from 0.984 to 0.986 mole fraction carbon dioxide.It was assumed there was enough 45°F cooling water to cool this stream to its condensation temperature of 85°F,This stream was simply pumped to the NETL pipeline quality specification pressure of 2200 psi.If necessary,a distillation column can be added with minimal parasitic power to purify the CO,stream further.TIPS,because it is operated at a high pressure, has an integrated emissions control system.While ambient oxy-fuel systems require particulate control systems (Electrostatic Precipitator and/or baghouse),TIPS is able to scrub out particulate matter without these devices.As part of ThermoEnergy's contract with the Alaska Energy Authority (AEA),CANMET will be performing experiments on the back end of the TIPS process.The Peng-Robinson Equation of State was used for calculations of both the condenser and the CQ,pump in the simulation.Figure 4 shows the layout of the CO)pumping process used in Aspen Plus. Figure 4 Aspen Plus Layout of CO,Condensation and Pumping 15 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 PERFORMANCE RESULTS FOR 8 CASES Base Case (Dry Ash) The base case used no slurry and was intended for comparison purposes to determine the extent of efficiency losses in the slurry cases.Usibelli Coal was assumed to be directly injected into the combustor.The coal was assumed to enter the system at 14.7 psia and 59°F,and was pumped to 80 bar before entering the system.This system only required the devices previously discussed in this report.1,336 tons/day of coal were required to provide enough heat for the ultrasupercritical steam cycle which produced 127.5 MW of gross power.The parasitic power losses in this case resulted in 100 MW of net power.254.7 MW of heat were input from Usibelli Coal and the total efficiency (HHV)of this system was 39.3%. Base Case (Slagging) The slagging case had a furnace outlet temperature of 2700°F as opposed to the 2300°F temperature in the dry ash case.This resulted in less coal being used to generate the same net power.1,309 tons/day produced 127.0 MW of gross power and 100 MW of net power.249.5 MW of heat were input from Usibelli Coal and the total efficiency (HHV)of this system was 40.1%,a 0.8%increase from the dry ash case. 50/50 Coal/Water Slurry (Dry Ash) This case was more realistic as it pumped a 50/50 mixture of coal and water into the combustor. Since Usibelli Coal has 26%moisture in the coal,enough water to bring the percentage up 24 points was added.The water was assumed to enter the slurry mix at 14.7 psia and 59°F,which were the same conditions as the coal.This mixture was pumped to 80 bar before entering the combustor.This system used the same devices as the base case.1,461 tons/day of coal were used to provide the heat for the 130.0 MW gross power steam cycle.The net power was 100 MW due to the parasitic power.278.4 MW of heat from the fuel were input resulting in a total efficiency of 35.9%.This was a 3.4%efficiency drop from the base dry ash case. 50/50 Coal/Water Slurry (Slagging) The slagging case for the 50%solids case made more of a difference than the base case because there was more latent heat available for capture and the 400°F difference in the flue gas temperature difference across the convective heat exchanger accounted for a larger amount of heat used to superheat and reheat the steam.1,358 tons/day of steam were used to generate 128 16 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 MW of gross power and 100 MW of net power.258.8 MW of heat were input from Usibelli Coal and the total efficiency (HHV)of this system was 38.6%,a 2.7%increase from the dry ash case, and a 1.5%efficiency drop from the base slagging case. 60/40 Coal/Water Slurry (Dry Ash) Because the 50/50 mixture caused a relatively large drop in efficiency,and a 60/40 coal/water slurry is somewhat realistic,the case was simulated with 60%solids.The added water was again assumed to have the same conditions as the Usibelli Coal (14.7 psia and 59°F).This mixture was also pumped to 80 bar prior to entering the combustor and used the same devices as the base case. 1,388 tons/day of coal were input to provide the heat for the steam cycle.The net power in this case was 100 MW and 264.6 MW of heat from the fuel were input.The total efficiency in this case was 37.8%which is only 1.5%less than the base case.342 tons/day were added in this case, which is only 46.7%of the added moisture as the 50/50 coal/water slurry case. 60/40 Coal/Water Slurry (Slagging) The slagging case using 60%solids was very close to the base slagging case since the convective heat exchanger captured almost all of the latent heat of the 40%moisture.1,310 tons/day of coal were used to produce 127.2 MW of gross power and 100 MW of net power.249.8 MW of heat were input from Usibelli Coal resulting in an efficiency (HHV)of 40.0%.This was only a 0.1% drop from the base slagging case. Alternate Injection (Dry Ash) An alternate method of injection was examined and this method remains proprietary at the time of this paper.This method used 50%solids and another fluid.The mixture was again pumped to 80 bar before combustion,but there were some added devices necessary in this model.In this case,1,401 tons/day of coal were input to provide the necessary heat to the steam cycle. Although this case offered major advantages,the 2 other devices added to the system resulted in a drop in efficiency.The total efficiency of the system was 37.4%,which is 0.4%less than the 60/40 coal/water slurry injection method. 17 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Alternate Injection (Slagging) The slagging case for the alternate injection method resulted in a 1.1%efficiency gain from the dry ash case.1,364 tons/day of coal were pumped in with the liquid to produce 130.7 MW of gross power and 100 MW of net power.The resulting efficiency (HHV)was 38.5%. Comparison of Different Slurry Methods Table 3 shows a comparison table for the 4 different cases using dry ash in this study.Outside of the base case,the 60/40 Coal/Water slurry case has the highest overall efficiency at 37.8%.This is only a 1.5%drop from the base case with no slurry.The alternate injection method uses slightly more coal than the 60%solid slurry,and has a lower overall efficiency due to the two extra unit operations needed to operate the alternate injection.An analysis would be necessary to determine which method would be more realistic.Since the recycled flue gas controls the furnace outlet temperature to 2300°F in every case,the no slurry case required the most amount of recycle because it had the hottest flame temperature with no recycle.The 60%solid slurry required 557 tons/day (TPD)more recycle than the alternate injection method and 797 TPD more recycle than the 50%solid slurry case. The higher heating value was 7,800 Btu/Ilb for Usibelli Coal and this number was the same for all four cases.No changes were made to the steam cycle for a fair comparison between the different injection methods.The ASU auxiliary power was calculated by dividing the tons per day in the 95%oxygen stream by 112.The oxygen compression auxiliary power came from the previously described 6-stage system with inter-stage cooling to 80°F.The BFW pump's auxiliary power did not change and stayed at 1.67 MW for all four cases.The CO2 product pump auxiliary power was calculated by pumping the liquid from 80 bar to 2200 psi with a pump efficiency of 0.8.The other devices in the alternate injection case caused the overall efficiency to drop below the efficiency of the 60%solid slurry case.Table 3 shows the effect that moisture content in the slurry has on the overall efficiency.This is the advantage of TIPS over atmospheric processes. Where atmospheric processes would use splits within the steam cycle to heat the feed water, TIPS is able to use 100%of the steam to produce power and heat the feed water with the latent heat from the condensing heat exchanger.Table 4 shows the same details as Table 3 for slagging combustion. 18 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Table 3 Comparison Table of Three Slurry Cases and Base Case Using Dry Ash Combustion No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Coal (TPD)1,336 1,461 1,388 1,401 Water Added 0 701 324 0 (TPD) 95%Oxygen 1,862 2,028 1,939 1,953 Stream (TPD) 95%Oxygen 460 502 480 483 Stream (ACFM) Flue Gas Recycled 11,365 9,926 10,723 10,166 (TPD) Flue Gas Recycled 1,214 1,060 1,145 1,052 (ACFM) Furnace Outlet Gas 14,474 14,016 14,282 14,827 (TPD) Furnace Outlet Gas 12,832 13,331 13,084 13,112 (ACFM) Coal HHV (Btw/Ib)7,800 7,800 7,800 7,800 Gross Power 127.5 130.0 128.7 131.5 (MW) Auxiliary Power (MW) ASU 16.6 18.1 17.3 17.4 Oxygen 8.9 9.8 9.3 9.4 Compression BFW Pump 1.57 1.60 1.60 1.62 Product Pump 0.38 0.42 0.40 0.4 19 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Other Devices |No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Net Power (MW)N/A N/A N/A 2.5 Heat In (MW)100 100 100 100 Efficiency 254.7 278.4 264.6 267.0 (%HHV) CO?Product 39.3 35.9 37.8 37.4 (TPD) CO)Purity 2,291 2,503 2,380 2,403 (Volume %) 94.2 94.2 94.2 96.0 Table 4 Comparison Table of Three Slurry Cases and Base Case Using Slagging Combustion No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Coal (TPD)1,309 1,358 1,310 1,364 Water Added 0 652 306 0 (TPD) 95%Oxygen 1,824 1,885 1,830 1,901 Stream (TPD) 95%Oxygen 451 467 453 470 Stream (ACFM) Flue Gas Recycled 8,657 6,828 7,711 7,391 (TPD) Flue Gas Recycled 926 732 826 765 (ACFM) Furnace Outlet Gas 11,702 10,631 11,070 11,927(TPD) 20 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Furnace Outlet Gas 12,023 11,897 11,835 12,223 (ACFM) Coal HHV (Btu/Ib)7,800 7,800 7,800 7,800 Gross Power 127.0 128.0 127.2 130.7 (MW) Auxiliary Power (MW) ASU 16.3 16.8 16.3 17.0 Oxygen 8.8 9.1 8.8 9.1 Compression BFW Pump 1.56 1.57 1.57 1.61 CO2 Product 0.38 0.39 0.37 0.39 Pump Other Devices N/A N/A N/A 2.6 Net Power (MW)100 100 100 100 Heat In (MW)249.5 258.8 249.8 259.9 Efficiency 40.1 38.6 40.0 38.5 ("%HHV) CO,Product 2,244 2,327 2,246 2,338 (TPD) CO)Purity 94.2 94.2 94.2 96.0 (Volume %) CO,Product Impurities The CO)product stream ranged between 94.2%and 96.0%pure in the 8 cases in this study. However,there were some impurities in the stream and Tables 5 and 6 detail the conditions and 21 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 amount of components (ppm)other than CO,in the product stream.This stream could be distilled to produce a purer CO product stream if necessary.The vapor stream from the column would be compressed and recycled to help control the furnace outlet temperature.The distillation column is assumed to use minimal auxiliary power at this pressure. Table 5 Product Specifications Using Dry Ash Combustion No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Mass Flow,TPD 2,291 2,503 2,380 2,403 H20 Mole Frac 0.003 0.003 0.003 0.003 N>Mole Frac 0.029 0.029 0.029 0.019 O,PPM 384 435 414 394 SO2 PPM 1084 1014 1084 954 Argon Mole Frac 0.024 0.024 0.024 0.016 Table 6 Product Specifications Using Slagging Combustion No Slurry 50/50 60/40 Alternate Coal/Water Coal/Water Injection Mass Flow,TPD 2,244 2,327 2,245 2,338 H20 Mole Frac 0.003 0.003 0.003 0.003 N2 Mole Frac 0.029 0.030 0.030 0.019 O2 PPM 383 435 414 394 SO,PPM 1084 1017 1102 954 Argon Mole Frac 0.024 0.025 0.024 0.016 22 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Parasitic Power Loss Figure 1 shows the relative effect of each auxiliary power loss on the overall efficiency in the TIPS plant.The ASU remains the largest contributor to efficiency loss by a wide margin.The multi-stage oxygen compressor has a major contribution to efficiency loss as well,but after those two operations,no other device comes close to the parasitic power loss.The boiler feed water pump and the CO,liquid pump have a minimal effect in comparison.The other devices only apply to the alternate injection case.Oxygen production technologies that are currently in development could have the largest effect on the increase of oxy-fuel plant efficiencies.The most notable technologies are the ion transport membrane (ITM)technology developed by Air Products,Inc.,and Praxair,Inc.and the ceramic autothermal recovery oxygen generation technology developed by the BOC Group.More research is required to determine if these technologies will reduce the cost of oxygen production.It has been suggested that the ITM technology cost is 35%lower than the cost of cryogenic air separation,used in this simulation. w Series1 Op-NWAOON|ASUOxygenCompressionCO2PumpOther|Devices(AlternateInjection)|BFWPumpPercentDropinTotalEfficiencyDuetoParasiticPowerLossFigure 5 Effect of Specific Parasitic Power Losses on the Overall Plant Efficiency 23 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 CONCLUSIONS Based on the results of the cases modeled in Aspen Plus,the following conclusions can be made: Even with a low rank coal,such as the sub-bituminous Usibelli coal in these simulations, TIPS is able to use the majority of the latent heat of vaporization to heat the feed water. This is a major advantage over conventional and atmospheric oxy-fuel power plants. A 60%solid slurry with water is the best injection method as there is only a 1.5%drop in overall efficiency from the base case with no slurry and there are no added unit operations. The flash separation after the condensing heat exchanger provides a stream with over 98%pure CO).This could be purified further with a distillation column using minimal auxiliary power. The results of experimental work on the back end will clarify the integrated emissions control. Alaska is an advantageous locations for the TIPS process due to its low rank coals and its available cooling water at low temperature. TIPS can capture carbon dioxide at pipeline quality conditions with minimal auxiliary power. Modeling of a CO;Power Cycle Combined with Rankine Cycle Modeling efforts were made towards establishing if there was an advantage to using a modification to the steam cycle proposed by ThermoEnergy.The conclusion of this study was that it was more effective to send a Btu to the steam cycle than it would be to send a Btu to the CO power cycle.This study was concluded and ThermoEnergy moved forward using a Rankine Cycle with no steam splits. Heat Transfer Analysis Using Aspen TASC+ Aspen TASC+was used to compare the heat transfer characteristics of atmospheric oxy- fuel and pressurized oxy-fuel.This did not take into account the fluidized bed.It assumed an 88:12 (mass)CO2:H2O mixture in the flue gas.The temperatures,pressures,and flow rates of steam and the flue gas were taken from the Usibelli Coal 100 MW Aspen Plus model.In each case,the flue gas was shell-side and steam was tube-side.The tube material,dictated by the steam temperature and pressure,was assumed to be Hastelloy G for both pressurized and atmospheric oxy-fuel.Table 1 is a breakdown of the results of this analysis. 24 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Table 7 Results from Aspen TASC+Heat Transfer Analysis Superheater Oxy-Combustion |Steam Heat Heat Transfer Effective Pressure Pressure |Transferred |Coefficient Surface Area |Total Cost psi psi Btu/hr Btu/(h ft F)fP USD 14.7 4015 4.84E+08 5.19 427,946 $111,276,000 1160 4015 4.84E+08 62.4 37,639 $6,324,410 Reheater 1 Oxy-Combustion |Steam Heat Heat Transfer Effective Pressure Pressure |Transferred |Coefficient Surface Area Total Cost psi psi Btu/hr Btu/(h ft*F)ft USD 14.7 438 1.90E+08 3.40 322,405 $80,313,000 1160 438 1.90E+08 33.1 33,042 $4,364,420 Reheater 2 Oxy-Combustion |Steam Heat Heat Transfer Effective Pressure Pressure |Transferred |Coefficient Surface Area Total Cost psi psi Btu/hr Btu/(h ft?F)ft USD 14.7 27 1.83E+08 1.18 840,246 $141,771,000 1160 27 1.83E+08 22.3 48,991 $6,003,060 These remarkable results show the large impact of a higher heat transfer coefficient on both size and cost for boiler heat exchangers.Note that these numbers were generated by an extremely sophisticated,industry standard,validated software package specifically written and offered to do exactly these types of calculations and cost estimates.The cost estimates also may explain why electric utilities have not generally pursued second reheat processes for conventional pulverized coal fired power plants.The relatively low heat exchanger cost projected for a TIPS system would make a second reheat economically feasible.Adding a second reheat will generally add 4 percent to the overall efficiency of a steam power cycle.With a second reheat, the TIPS process can reach higher power production efficiencies than other cycles,including IGCC in its best configuration,can attain.This is a significant finding. 25 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 These results may actually be understated due to the fact that Aspen TASC+had to extrapolate data for the 1,160 psi case.The results from ThermoEnergy's lab experimentation showed substantially higher actual heat transfer rates than the TASC+model showed. Liquid Nitrogen Plant A natural gas TIPS plant was modeled to determine whether a TIPS plant could power a liquid natural gas facility.It was assumed that 100 lb/hr of natural gas combusted with pressurized oxygen.This required 372.9 lb/hr of 80 bar liquid oxygen and 1191.6 Ib/hr of liquid nitrogen would be produced.The energy consumption was assumed to be 360 kWhrs/ton 97.5%LOx produced (Air Products approximation).The liquid nitrogen energy consumption was assumed to be 1.3 kWhrs/liter Nitrogen produced ("Optimization of parameters of recirculating apparatus for obtaining liquid nitrogen using mixtures,"Chemical and Petroleum Engineering,Volume 29, Number 12,December,1993).This number turned out to be within 1%of the number that Air Products and Chemicals Corp.provided later. Using these assumptions,the energy consumption for liquid oxygen production was calculated to be 67.1 kW and the liquid nitrogen production energy consumption was 898.6 kW.Overall,the plant energy requirement was 982.6 kW.Using an Ultrasupercritical steam cycle,the plant with 100 Ib/hr of natural gas produced 306.2 kW,which was 31.2%of the liquid oxygen/liquid nitrogen plant requirement.The rest of the energy would need to be imported. Eight Pound Steam Generation A Flowsheet for integrating the heat from cooling the air from compression in the air separation plant was developed to determine how much eight pound steam energy could be produced per energy used to compress ambient steam to eight pounds.Assuming 10,000 lb/hr of air at 350F was cooled to 100F and this heat was used to evaporate 1,000 lb/hr of boiler feed water at 100 F and 0.5 psia and 500 lb/hr of cooling water at 100F and 14.7 psia,7.74 *10°Btu/hr of energy was produced in the form of 8-pound steam,and 851,800 Btu/hr of energy was used to compress the steam from 0.5 psia to 22.7 psia.The ratio of Steam heat to power consumption was 9.1. Coal to Liquids Plant Using TIPS to Combust Fischer Tropsch Tail Gas A coal to liquids plant was presented (3).This plant used a conventional air fired boiler to burn the Fischer Tropsch (FT)tail gas and produce power to run the coal to liquids plant. ThermoEnergy modeled a case where the boiler would be replaced with a TIPS boiler.This case resulted in a more effective overall plant. Figure 6 shows the typical CTL plant (3).Coal is transported through a gasifier where it is gasified using an oxygen stream for an air separation unit (ASU).The gasification product is sent through a series of treatments including COS removal,Hg removal,Selexol and sulfur polish. This produces a stream that is ready to enter the Fischer Tropsch reactor and produce diesel and 26 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 naphtha along with a combustible tail gas.The combustible tail gas enters an air fired boiler and produces 145.1 MW of power,135.4 MW are used to power the CTL plant,so it is left with 9.7 MW of net power.The boiler island efficiency is significantly improved using TIPS. To CO,Compression H, (795 TPD Carbon)tA CO,Injection Gas (200 TPD Carbon)-#H,Recovery Fuel Gas (11 TPD C) ,|Gasification Cc SulfurCoatQuench>td Selexol Polish4,891 TPD (2 Gasifier Trains) (3,118 TPDCarbon)Hg Oxygen Removal | SHIFT AGTAir-->ASU Siag y (31 TPDCarbon)7 FT SynthesisToCO,Compression co,(851 TPD Carbon)"Removal (4FT Steam 9.7 MW Net Power 135.4 MW Plant Power Reactors)|q Ad ST ; <Product 145.1 MW]Boiler Recovery/|Upgrading__»"me "7,500 BPOMake-up CW ; Water System (1,206 TPD carbony{NaphthStackGas»Naphtha (224 TPD Carbon)3,509 BPD Figure 6 Block Flow Schematic of the Coal Only CTL Plant Figure 7 shows the CTL plant using TIPS to combust the tail gas and produce electric power. The selexol would be replaced with a Rectisol wash to purify the gasifier product.The energy from heating the liquid oxygen from -182F to 60F before combustion would be used to cool liquid methanol used in the Rectisol to -40F.The case with TIPS was assumed to produce the same amount of diesel and naphtha and the same amount of carbon was left in the FT tail gas. The tail gas was assumed to have the following volume percentages,based on a paper by Rentech (4)and an NETL paper (3)saying how much carbon goes into the liquid product:54.5% hydrogen,3.58%carbon monoxide,19.1%methane,17.3%carbon dioxide,2.71%argon, 0.509%nitrogen,1.98%ethane,0.243%butane and 0.119%butane.The overall carbon balanced within 0.03%,the overall hydrogen balanced within 0.79%and the overall oxygen balanced within 1.8%when 120,000 Ib/hr of water were added to the water gas shift reactor. 27 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 ---Oxygen sean 'iecti Claus Plant --Steam CO,injection Gas (200 TPD Carbon)w/tail gasSufurcleanup y Sulfur \KGasification4cos SulfurCoal--}Quench >Hyd Rectisol Polish 4,891 TPD (2 Gasifier Trains) (3,118 TPD HgCarbon)Removal Oxygen CO,forWGSTemperature Air -->}ASU Slag (Optional)Qo Control | (34 TPD Steam|Carbon)(Optional)y FT Synthesis co.(4 FT Steam 2 114.1 MW Net Power pet Mw Compressor Reactors) Power loxygen 7 a sT ky TPS |e .Tailgas |Reo,a i ompressor <7,249.5 MW Boiler pI |Tailgas Upgrading -->ald 7500 BPDMake-up CW , Water System (1,206 TPD carbony{Naphtha|CsPipeline Quality Liquid Product 3,209 BPD(1,881 TPD Carbon) Figure 7 Block Flow Schematic of CTL Plant with TIPS Heat Integration Several heat sources available in the coal to liquids plant were used in the Rankine cycle.The gasifier waste heat that was above 640F was used to superheat and reheat steam.There was 8.04 *10°Btu/hr available at temperatures above 640F and this was integrated with the steam cycle in the superheat/reheat balance.The outlet gas from the water gas shift was 806F and was cooled to 640F providing 7.75 *10'Btu/hr to the steam.Also,cooling the Fischer Tropsch gas from its exit temperature of 3175F to 640F provided 6.33 *10°Btu/hr to the steam cycle.The heating of the liquid oxygen from -182F to 60F provided -8.5 *10'Btu/hr of cooling energy to cool liquid methanol to -40F for the Rectisol wash and to condense the CO)rich TIPS product.There was also 4.5 *10°Btu/hr of waste heat available from the ASU compression interstage coolers which kept the air above 80F.This heat,combined with the lower grade gasifier product cooling to 220F which provided 1.51 *10°Btu/hr,were used to heat the boiler feed water.The waste heat from cooling the FT product from 640F to 77F was used to heat the WGS inlet from 75F to 400F. Comparison of TIPS Configuration with Air Fired Boiler Configuration The TIPS configuration showed a significant improvement over the air fired configuration described in NETL's paper in both thermal efficiency and carbon capture.It was assumed that 28 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 the same amount of energy was produced in the diesel and naphtha.Therefore,the only difference in thermal efficiency came from the electricity produced in the steam cycle from the boiler.The ability to integrate all the heat from the coal to liquids plant into the steam cycle was a key reason why the TIPS configuration had such a high overall thermal efficiency (58.8% compared to 51.3%in the air fired case)while still capturing 98.0%of the carbon (53.3%in the air fired case).This is assuming a subcritical steam cycle using 2 reheats.Table 8 summarizes the net power calculation in the TIPS case. Table 8 Net Power Calculation for TIPS CTL Plant Gross Steam Power 299.2 MW Oxygen to TIPS 96918.5 Ib/hr Oxygen to TIPS 48.5 Tons/day ASU/LOX Pumping for TIPS Oxygen Work 17.4 MW Tailgas Compression (to 1,160 psi)0.2 MW Rectisol CO2 to TIPS Compression (to 1,160 psi)20.7 MW Product Pump Work 0.8 MW BFW Pump Work 4.2 MW Rectisol Work 6.5 MW TIPS Power 249.5 MW CTL Plant Power 135.0 MW Net Power 114.5 MW Table 9 shows the inlet stream to the condensing heat exchanger,the liquid removed above 82F, and the product which is pumped at 28.5F.This stream could be distilled to produce a purer CO2 stream if necessary but the purity requirements depend upon the application. Table 9 Condensing Heat Exchanger Inlet/Outlet Mass Flows Cond HX Inlet Mass Liquid Out Mass Flow Flow CO2 Rich Product Stream lb/hr Ib/hr lb/hr H20 67,994 67,456 538 CO2 558,260 1,036 557,223 AR 41,413 10.8 41,402 N2 5,040 0.219 5,040 02 736 0.191 736 Total 673,443 68,504 604,938 29 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Conclusions It is clear from this modeling that there is a major advantage to using TIPS to burn the FT tail gas in the CTL plant.Since the hydrogen,oxygen and carbon balanced in the plant and the known amount of carbon in the tail gas was sent to the TIPS boiler,the results generated from this model should be accurate.The heat streams from the gasification product were generated directly from a previous NETL Aspen Plus model.Since the tail gas is already at a high pressure ( 40 bar)and has already been cleaned up in the coal to liquids plant,this would result in a highly efficient TIPS plant.The diesel and naphtha produced would be the same quantity as in the conventional case,but there would be over 100 MW more net power and almost twice as much carbon captured. From the modeling phase of this project,it is clear that there are two main ways of using TIPS for usage of Alaskan coal.One is by direct burning of coal for electricity as shown in the Usibelli Coal modeling.The other is the indirect method of burning the coal to liquids tailgas.Both of these methods show clear advantages of using TIPS for carbon capture.The direct method shows several different slurry methods and efficiencies of near 40%with near 100%carbon capture. The CTL modeling shows a major upgrade in electric performance with another major upgrade in carbon capture.This indirect method is also attractive due to the fact that the diesel and naphtha are already produced.The electric power is a bonus addition on the end of an already efficient plant.The extra carbon that is captured in this process could be used for multiple applications including enhanced oil recovery,sequestration and food transport. 30 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Part 2:Testing of a Pressurized System to Generate Physical Property Data on Synthetic Exhaust Gas Streams There were two test stations built and operated in ThermoEnergy's Hudson,Massachusetts lab. One was a Thar Instruments Phase Monitor which had a video monitor so the user could observe the condensation of CO?or a mixture gas at a given temperature and pressure.The other test station was a heat exchanger test stand which used cooling water in a countercurrent tube-in-tube exchanger so the user could calculate heat transfer coefficients at several different conditions for the gas and different gas mixtures. Heat Exchanger Unit The purpose of the current research on heat transfer was to experimentally validate the heat transfer model and estimate pressurized gas side heat transfer coefficients used in the Aspen model.In order to reduce complexity a natural convection approach was selected.Mixtures of CO;rich gas were tested at various pressures and temperatures to determine the heat transfer coefficients as a function of pressure. 1°Stainless Steel Tubing Ya'Stainiess Steel Tubing 1/4"Copper Tubing %'Plastic Tubing IC rindYylinder =«"Gas Out RTD eet ValveHero"Jean2tae|PTWaterOutWaterInBallVave To Exhaust Yv []..Tweed Bleed poy MEM*Thermocouple P a | ¥-1/4"Union A v 1°-%"'Union ry ot PRV Vv %-17 Union Figure 8 HX test unit flow diagram 31 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Figure 8 shows the HX test apparatus flow diagram.A heat transfer loop that is actively heated on the bottom left and actively cooled on the top right has been set up using standard components and data acquisition instrumentation.The heater is a Watlow CAST X 2000. Stainless steel tubing on the hot side is insulated.The other key heat transfer item is the gas cooler.An Exergy tube in tube heat exchanger,that was water cooled,was selected for the cooling duty. The other key component is the mass flow monitor.A Micro Motion Coriolis ELITE sensor is placed on the cool side of the thermosiphon loop.This monitored the actual CO,flow real time and reported to the National Test DAS.The cooling water flow was indicated with an in-line visual indicator flowmeter and also was measured manually using a scale and a stopwatch. (accuracy .02%)The temperature measurements on both the gas and water were made with RTD monitored by a National Instruments data acquisition system.The gas pressure was monitored by both pressure transducer through National Instruments data acquisition and pressure gauge (accuracy 0.25%). Equipment List - Watlow CAST X 2000 Heater Micro Motion Coriolis ELITE sensor and flow indicator. RTDs Pressure transducer and Pressure gauge National Instrument data acquisition package Water flow indicator Micro GC Experimental Design CO,and Argon were used to check for leaks in the system first to ensure that there was essentially no leakage.Both pure CO,and pure Argon were used to estimate the heat transfer coefficient initially.The reason to use pure components first is a)to familiarize the system, especially the heater;b)to familiarize the data acquisition system and data analysis method;and c)to compare the data with a reference gas. The next step is to use an Ar-CO>gas mixture.The amount of Ar and CQ)mass were controlled by the gauge and estimated using gas properties table.Ar-CO2 mix composition we looked at were: 5%Ar and 95%CO).Other gases like SO2 and N2 were used in low volume.These two gases had a low volume and were assumed to have an insignificant role in heat transfer as the majority of the gas was still Argon and CQ). The pressure range we focused on was around 200 to 1,300psi.We compared the high pressure data with medium or low pressure (200psi)data. 32 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Test Variables Pressure: 200psi to 1300psi Gas:pure CO2,Ar-CO,mixtures ranging from to 15:85. The system is a natural convection loop and the temperature differential and gas density are related directly to the gas flow rate.By changing pressures and temperatures we can modify the gas flow rate to low,medium and high.The flows are typically in the laminar regime at low pressure and turbulent at higher pressures and flows. We also used the GC to confirm the mixture gas concentration before bleeding the gas from the system. The National Instrument data acquisition collected all the data points (Temperature,mass flow rate,pressure).The data was recorded every 0.5 sec and smoothed using an average based on 5 minutes. Practical Experimental Technique During the testing and shakedown of the heat transfer equipment unit it became apparent that there is a lag time between the time the heater and associated piping as well as the cooler and cooling water are up to operating temperature.The naturally convective flow pattern is not fully established and there is some variability due to the thermal inertia of the system.Therefore the test loop was operated for enough time to establish a relatively stable rate of convective flow and constant temperature profile for both the water and CO2.This assured we obtained the best and most representative data. Experimental Sequence The easiest way to obtain consistent composition,pressure and temperature data was to load the system with a high pressure of gas or gas mixture and then conduct the high pressure runs. Lower pressure runs were then achieved by letting some gas out of the system to reduce the pressure.This approach ensured that the composition remained constant over a given set of pressure data points. Experimental Procedure 1.Inject gas or gases to the desired pressure with system at room temperature. 2.Turn on the heater and water,the heater set point is based on the heater temperature we want to achieve and the total pressure is controlled by the average temperature of the gas in the loop which is controlled by the heater temperature and the water flow rate. 3.Once the mass flow rate is stabilized,start recording data (Temp,gas outlet pressure,gas inlet pressure is estimated based on the CO2 tab,water flow rate and mass flow rate)The figure below shows the temperature of the gas over a period of time.Because the temperature is highly variable in the beginning,data would only be collected once the gas temperature stabilizes (at approximately data point 6500,or 55 minutes) 33 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 140 120 100 | 80 - 60 40 20 0 2000 4000 6000 8000 10000 12000 14000 4.In order to estimate heat transfer coefficient,the water flow meter was set at different flow rates and the experiment was repeated;the water flow was measured manually with a stop watch and a tared container. 5.Approximately 1 to 1.5 hours of data was collected at both a high ( 210°C)and low ( 120°C)temperature per pressure level. 6.After collecting the final set of data from a certain gas composition,the remaining gas in the heat exchanger was analyzed via gas chromatography to determine the exact composition of the gas. Data Analysis Method: Analysis to determine heat transfer coefficient for tube-tube counter-flow heat exchanger Heat transfer in a counter flow heat exchanger can be expressed: Equation 1 Q =UA,,AT,y, Equation 2 34 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 A TL=Ti20-T co2 at the "L”location of the heat exchanger,which is the CO)outlet and water inlet temperature,K; A To=TH20-T coz at the "0”location of the heat exchanger,which is the CO}inlet and water outlet temperature,K. Q =total heat transferred between the water and carbon dioxide over the entire heat exchanger length,W; Ant =heat transfer area between the water and carbon dioxide,based on the inner tube inside radius,m?; U =overall heat transfer coefficient,W/m”.K; A Tim =log mean temperature difference,K The heat transfer coefficient of the water side is 0.15 BTU/ft*2-sec-R.(source:Warr Mui, Application Engineer,Exergy Corp.)The thermal resistance of the metal is very small and the gas side comprises most of the heat transfer resistance. The overall resistance to heat transfer,1/U,,based on the inside area of the tubes,is the sum of four resistances in series: Equation 3 Alt DDR DA yyU;h,'02 2k,D,D,hin Where hco2 =carbon dioxide heat transfer coefficient,W/m”.K ; Dj,=inner tube diameter,m; Ky =thermal conductivity of the stainless steel of the tube,W/m.K; Do =inner tube outside diameter,m; hy20 =water heat transfer coefficient,W/m'.K F =fouling factor,equals 0 at this application Eq.(2)defines both hco2 and hy20 as "average”coefficients that a single value for the entire tube length.In order to determine hco2 as a function of position along the tube,we would need to know the heat flux as a function of position,or the specific enthalpy of either the water or carbon dioxide as a function of position. 35 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 We calculated "Q”from the measurements of the heat absorbed by the water and heat released by the carbon dioxide. Equation 4 QO =Qo...=Moor (iy,-iy cor O =Qi a9 =M20(i,-by)420 -Qross Where Mco2 =carbon dioxide mass flow rate (measured),kg/s; M120 =water mass flow rate (measured),kg/s; i =specific enthalpy at location L or 0 for water or CO2,KJ/kg; Qioss =heat loss from water through tube insulation to the room,W. The specific enthalpy was calculated from thermodynamic equations of state for the water and carbon dioxide at the measured temperature and pressure,P.The equation of state of Span and Wagner (1996)was used for the carbon dioxide/CO,tab,and the NIST Steam Tables were used for water (Gallagher and Haar,1988)/Steam tab.Qios;was measured as a function of water temperature by operating the water flow loop without carbon dioxide. Heat transfer coefficient estimation method We have obtained the water side heat transfer coefficient (hy20)from the manufacturer of the heat exchanger and all experiments were run at laminar flow on the water side.To determine CO,'s heat transfer coefficient (hco2)at each test point,the heat flow was calculated from the measured temperatures,pressures and flow rates using Equation 4.The average of Quo and Qco2 was used in Eq (1)along with the measured temperatures to calculate total heat transfer coefficient U.The value of carbon dioxide heat transfer (hco2)was then calculated from Equation 3. Dimensionless Analysis for Free Convection In free convection fluid motion is due to buoyancy forces within the fluid,while in forced convection it is externally imposed.Buoyancy is due to the combined presence of a fluid density gradient and a body force that is proportional to density. Reynold's number cannot be used as a measure of the degree of turbulence encountered in natural convection.In its place,the Grashof number (Gr)was introduced. 36 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Equation 5 _p -g°B-AT->x? 2Hu Gr where AT is the difference between the wall and the free stream temperatures.where B,the volumetric thermal expansion coefficient,is defined as follows: me P The volumetric thermal expansion coefficient,B,is a thermodynamic property.It is often tabulated as a function of temperature and pressure for many real gases.In the very special case of an ideal gas, aoP"RT So that 2)aOT),R-T? Substitute into the definition of B and simplify: gatiT Natural convection correlations appeared much like those for forced convection.The general equation was: Nu,=C-Gr™.Pr” In many cases we found that the exponent on the Grashof number and the Prandtl number were identical: Nu,=C-[Gr,-Pr]” 37 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 In this case it is common to combine the two non-dimensional variables into a single non- dimensional variable,the Rayleigh number. Ra,=Gr,-Pr So that: Nu,=C-Ra,™ In this case,the Raleigh number is often used as the indicator of the flow regime. Notes In high pressure situations,a discrepancy was noted between the total heat of the gas (Qgas)and that of the water (Qwater).Qwater Was over 1000W higher than Q,,s.The high pressures and the rapid cooling from over 100°C to 25-35°C causing some of the gas to condense is a likely explanation.The difference in Q values may be explained by the large heat of vaporization of carbon dioxide. Heat Transfer Analysis Results Summary From the data compiled from several runs of the heat exchanger test stand,a 3D plot of the calculated heat transfer coefficients vs.pressures and Reynolds numbers was generated using DataFit 8.2.79.This plot is from 35 points including all of the Reynolds numbers above 10,000 as we expect to run the actual heat exchanger in turbulent mode on the CO,-Ar side.The coefficient of multiple determination (R')was 0.970.An R?value of 1 would mean there was no variance so the results are about 97%accurate using this determination.Figure 10 is another indicative plot which shows the Nusselt number vs.Reynolds and Prandtl numbers.This plot is also taken from 35 data points and has a more accurate R?value 0.986. 38 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Heat Transfer Coefficient vs.Pressure and Reynokis Number WIM Watoyeod Jajsuel) 123H888&§&$8«o JaquINN yassnyLALLYbey 8 SWAN ee -<- 80 aGe/0208, ¢LAANLATAa Cu, AGar: WEi | iTEWimaneeei:ma KY § Z Wp|Hyeiy ry. \¥ as 2 @ e ae = \/ F = 3g 2 es eeeeeeeeeeeeeeee| #8$$88&88° s¢ eesagegsgeseeegeRee WWM welsIyacg Jajsuel! yea} ef JOqUUNN WeSSNN fa Figure 9 DataFit 3D Plot of Heat Transfer Coefficient vs.Pressure and Reynolds Number 39 ° eral +c/KtA2edie+en22 -- Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Figure 10 DataFit 3D Plot of Nusselt Number vs.Reynolds and Prandtl Numbers Comparison of Experimental Data with TASC+Model Results The mass flow rates,pressures,inlet temperatures and outlet temperatures were input into Aspen TASC+for all 35 points used in the plots from Figures 9 and 10.Aspen TASC+takes those inputs and produces an optimal shell &tube heat exchanger design.The material was assumed to be carbon steel in TASC+.There were 34 points taken in the comparison of the Aspen TASC+ heat transfer coefficient vs.the experimental heat transfer coefficient vs.Reynolds number. Figure 11 clearly shows that the gap between the experimental and modeled heat transfer coefficient becomes dramatically higher with increasing Reynolds number.This demonstrates the fact that the correlations used in the model are conservative for higher Reynolds numbers. This is a significant finding.Figure 12 shows the heat transfer coefficients vs increasing pressures for both experimental and TASC+.This looks very similar to Figure 11 because the Reynolds Number increases with pressure. Heat Transfer Coefficient vs Reynolds Number 600 5 500 - £Lo | s=.400°aY300=7 as200|+ra Ad +peat ee -° 10,000 20,000 30,000 40,000 50,000 60,000 70,000 Reynolds Number #Total Heat Transfer Coefficient Aspen (W/m2k) =Total Heat Transfer Coefficient (U)Experimental Wim2K --Linear (Total Heat Transfer Coefficient Aspen (W/m2k)) --Linear (Total Heat Transfer Coefficient(U)Experimental Wim2k) Figure 11 Heat Transfer Coefficient vs.Reynolds Number (Experimental vs.TASC+) 40 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Heat Transfer Coefficient vs.Pressure HeatTranferCoef.Wim*2KhbOo(om)r=\|300 x 200 _ 100 *+ * 0 4 o 400 600 800 1,000 1,200 1,400 Pressure psi @ Total Heat Transfer Coefficient (U)Experimental Wim2K @ Total Heat Transfer Coefficient Aspen (W/m2K) Linear (Total Heat Transfer Coefficient (U)Experimental W/m2K) ----Linear (Total Heat Transfer Coefficient Aspen (W/m2K)) Figure 12 Heat Transfer Coefficient vs.Pressure (Experimental ys.TASC+) Discussion of Results The heat transfer coefficients measured experimentally were much greater than predicted in the model.The disparity between the experimental and modeled data grew as Reynolds numbers and pressures became greater.From this data,one can conclude that the benefits of using TIPS for lower volume vessels are even greater than expected.At pressures above between 600 and 1,400 psi,the experimental data shows a heat transfer coefficient between 3 and 4 times greater than the heat transfer coefficient predicted by Aspen TASC+.The same can be said for Reynolds numbers between 20,000 and 70,000.Since the heat transfer coefficients for pressurized oxyfuel were already predicted to be between 9 and 11 times greater than atmospheric oxyfuel,the experimental data would suggest that the actual ratio of pressurized oxyfuel to atmospheric oxyfuel heat transfer coefficient would be between 27 and 44. 41 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Liquid Vapor Equilibrium There are two main classes of experimental methods that are used to determine high-pressure phase equilibrium,analytical (or direct sampling)and synthetic.Analytical methods involve using some type of physical or chemical detection system to determine equilibrium phase composition,usually involving the removal of a sample from the equilibrium cell.Some typical problems associated with this technique involve disturbing the equilibrium conditions,especially near condition sensitive critical regions,and possibly preferentially sampling the more volatile component.Direct sampling methods are either done statically,with either constant volume or variable volume equilibrium cells,or are dynamic methods,where the equilibrium phase(s)are flowing either in a recirculation path or are continuously flowing out of the equilibrium cells.In addition,calibration of the physiochemical detection apparatus is often time consuming and can be eliminated by using a synthetic technique.A synthetic method avoids the problems of direct sampling by only observing the phase behavior of a known composition in the equilibrium cell. Synthetic methods do require high pressure apparatus with view windows or transparent materials.Phase behavior can be accomplished by observing the incipient phase change. In this work,we combine synthetic and analytical methods.The experimental apparatus is shown in Figure 13.CO2 phase change was observed using phase equilibrium analyzer through crystal sapphire window.The video output from digital camera for recording in the phase monitor is connected to the computer.The gas mixtures were continuously sent Micro GC for analysis. Commercial Phase Equilibrium Analyzer The commercial phase equilibrium analyzer was supplied by Thar Technologies.The system includes phase monitor with pressure and temperature sensors,swivel stand,CCD board camera, light source,rupture disc assembly,temperature display and control,digital pressure display, inlet and outlet 1/16”valves.Also,a phase monitor stirrer kit was included.The signal system of this camera is NTSC and uses a digital converter to transfer the image to the computer. The variable-volume equilibrium vessel consisted of a high pressure vessel (20mm i.d.)with two crystal sapphire windows and a movable plunger with a stirrer.The maximum volume of the pressure vessel is 15ml,and dead volume is Sml.The volume is adjusted by controlling of the movement of a plunger.The maximum pressure and temperature of the vessel are 412 bar and 150 C respectively. 42 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Gas Chromatography Agilent 3000A Micro GC with three channels is interfaced with a Dell Precision workstation. The Micro GC consists of multiple "channels"built inside of the GC.Each channel has its own injector,column and detector specific to a separation.There is a pump(s)inside which pulls sample through the GC inlet tubing and splits to each module (injectors).There is a 1/16"fitting on the front of the GC which can be connected to a process stream.Gas-liquid separator & pressure reducer fits on the front of the Micro GC and consists of a rotameter and membrane filter assembly on a bracket.The rotameter has a NPT 1/8"fitting and is used to meter the sample to the GC.The membrane acts to filter particulates and stop any liquid droplets from passing.Micro GC is connected to the computer through network cable (LAN port).Carrier gases for the GC are high purity of research grade gases. Gas Preparation Helium and Argon gases are the carrier gases for the GC unit.Both were research purity at 99.9999%.The size of both of the carrier gases was 1A.Pure Ar and CO?gases were used.The composition of Ar-CO2 mixture was controlled by pressure.Other gases,N2,O2,and SO2,were shipped in a predefined mixed by Matheson.Figure 13 shows Phase Monitor apparatus. 43 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Argon -co, --Helium . Argon--Sample Gas oy Cyl. aarey Sample Gas Argon Carrier Gases 2QFFigure 13 Phase Monitor Apparatus Experimental Design Calibrated all the instruments (temperature &pressure transducers,vessel volume,Micro GC) before any tests. In order to validate the experimental technique,the pure CO)phase equilibrium was investigated and the data obtained was compared with literature data. Studied CO,dew point at different gas/CO2 composition without water content.We looked at pure CO2,Ar-CO2 system and Ar-CO2-N2-SO2.Recorded the phase behavior at different temperature (our interest is at high pressure)and gas compositions. Before starting the experiment,the empty vessel was purged several times with CO, 44 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 e The amount of carbon dioxide was determined from the volume displacement of the pump and the density of carbon dioxide at the pump pressure and temperature calculated using the equation of state of Span and Wagner.Other gases loaded were determined from the known volume of the system and the pressure and temperature. e Gas/gas mixture was then heated until a homogeneous mixture is obtained. e Estimated CO phase equilibrium temperature.-By slowly decreasing temperature until the formation of a new phase was observed at desired pressure.Recorded temperature and pressure. e Gas mixture was then continuously sent to GC to be analyzed. e The matrix of gas mixtures were between 93 and 100 %CO2 with the balance being Argon and other specialized mixes. Thar Unit Procedural Notes To begin,the Thar unit was switched on.The interior of vessel was visible on the computer screen and the temperature and pressure readings were present as well.If the pressure inside the vessel did not read 0 bar,the contents of the vessel were released until the pressure read 0 bar. The vessel was then flushed several times with pure CO,gas from the gas cylinder to ensure that no other gaseous compounds were in the vessel.After flushing,the gas cylinder valve was closed and the excess gas inside the system was released. ja afis23-2008Ses |b O62 oe Thar Unit Inlet and Outlet Valve Hand Hydraulic Pump Using the hand pump hydraulic system,the vessel volume was decreased from its original 15ml to 5ml at which time the valve on the Argon gas cylinder was opened.Slowly,the valve to the Thar vessel was opened to allow a small amount of argon gas to enter the vessel.The pressure of the vessel was used to measure the amount of argon gas present,the temperature and pressure at this point was recorded.The gas cylinder and vessel valves were closed and the hydraulic valve is released such that the vessel reverts to its original volume of 15ml,the temperature and pressure at this point is recorded. 45 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 'd'!teeeGeeenae231aarai4]"ignHDISPLACENMGNT:|13.28.9009 k op.ss. Vessel Volume Indicator Thar Unit Controller Following the addition of argon gas,CO gas was added to the cylinder.This was done by fully opening the CO)gas cylinder valve as well as the vessel valve.Once the vessel was filled completely (the pressure remained stable)both valves were closed to isolate the vessel,typically at this point,the gas had condensed partially,if not fully.The temperature and pressure of the system was recorded. At this point,the stirrer within the vessel was turned on such that the stirrer was spinning ata _ moderately slow speed to ensure system homogeneity.Using the Thar controller,the vessel was heated up until no liquid was present in the system.From experimental trials as of 20 June 2008, this temperature was around 45 degrees Celsius. Once all the liquid within the vessel had evaporated,the heating elements were shut off and the vessel was allowed to cool.Periodically,the hand pump was used to increase the pressure of the vessel (by decreasing its volume).When the hydraulic system pressure was released,the vessel increased in volume and decreased in pressure.During this decompression,the video monitor was used to observe the inside of the vessel,specifically,to observe the presence of condensation. Condensation manifested itself as a white vapor cloud that appeared at the dew point -the point at which the gas begins to evaporate.If this was observed,the hand pump was used to determine the specific pressure at which the gas began to evaporate. 46 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Image before evaporation Evaporation The temperature and pressure of this point was recorded.As the vessel cooled,additional evaporate point measurements were collected at different temperatures,typically 1 or 2 points per degree Celsius.Once the temperature stopped decreasing,the cold air running through ice water was used to cool the vessel down as much as possible,during which time more data points were obtained. Once the final data point was collected,the gas composition was analyzed using a gas chromatograph.The gas was released slowly and controlled such that it flowed at about 30-40 ccm/s into the gas chromatograph.Multiple runs were performed until the results stabilized.The reports were printed out as pdf files and the composition of the gas was recorded. Liquid Vapor Equilibrium Testing Results Summary Figure 14 summarizes the cloud points at each composition and pressure run through the Thar Phase Monitor unit.When cooling the gas down in the unit,a cloud which is the first visible indication of liquid was seen at certain temperatures and pressures for each composition.The trend observed in the phase monitor unit was as expected.The pure CO2 condensed at the highest temperature and the temperature increased with increasing pressure.The more argon added to the mixture,the lower temperature at which the first condensation was observed.There have been 26 different mixtures,whose compositions were measured by the Agilent GC,run through the phase monitor as of the time of this report.Each of these mixtures'cloud points were recorded for 47 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 several different pressures.As displayed on Figure 14,there is more than enough data to establish an accurate trend. Data from Aspen Plus was also included in this chart to compare with the experimental data. Dew points were taken 600,800,1000 and 1200 psi for pure CO2,95%COz2,90%COz,and 85% CO)with the balance of the non-pure CO mixtures being Argon.The Peng-Robinson equation of state method was used in Aspen Plus to calculate the dew points at each of these mixtures and pressures.The comparison between the experimental data and the modeled data shows that the model is conservative in its prediction of the dew points at high pressures.Condensation was observed about 3 or 4 degrees Celsius higher than the dew points predicted in the Aspen Plus model.This is a significant finding that we can in reality produce a liquid at a higher temperature than modeled data shows. 48 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 @ 14%Ar-97.3%CO2 101 5 @ 7.2%Ar-92.3%CO2 99 4 a &34%Ar-96.3%CO2 97 4 x 2.2%Ar- -97.7%CO2 e K 3.3%Ar-96.9%CO2 @ 2.3%Ar-976%CO2 5.4%Ar-95.7%CO2 ©4.0%Ar-97.6%CO2 -3.1%Ar-94.1%CO2 Pure CO2 CO2 Tab 4.76%Ar-91.3%CO2 5.2%Ar-90.5%CO2 7 8%Ar -86.8%CO2 9.2%Ar --84.3%CO2 +96%Ar--848%CO2 =10.2%Ar--83.6%CO2 7.5%Ar --85.4%CO2 @ 115%Ar-90 4%CO2 11.6%Ar--88.5%CO2 11.6%Ar--87.7%CO2 x 12.5%Ar--87 0%CO2 *86%Ar--91.2%CO2 7.6%Ar--91.2%CO2 +Mixture Gas CO2 95.2% =Mixture gas CO2 97.4 -Aspen Pure CO2 m Aspen 5.0%Ar-95.0%+2Pressure,bare>»45 r ,r ,7 :r 'T :r T r ne 13415 #17 «#19 «21 23 2 27 29 #31 33 35 «6370639064406 «6490 Se aoeAspen15.0%Ar-Cloud Point Temperature,C Be Om COD Figure 14 Summary of Liquid Vapor Equilibrium Test Data (Cloud Point vs.Pressure) 49 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Figure 15 is a 3D plot from DataFit 8.2.79 which shows the cloud point temperature and the Aspen Plus Dew Points vs.pressure and CO,composition.This verifies the established trend of the dew point temperature increasing with pressure and increasing with increasing CO? composition when it is being mixed with Argon.The Aspen dew points are consistently at a lower temperature than the observed cloud points.Figure 16 shows a similar plot using the bubble point instead of the dew point.As expected,this shows a similar trend with increasing pressures and CO,compositions. e Aspen Dew Point -400 Pifffjy}}/ffffr}fi//{ff/yFigure 15 Cloud Points and Aspen Dew Points vs.Pressures and CO,Compositions Based on Peng-Robinson Correlation 50 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 e Aspen Bubble Point BubbiePointCFigure 16 Bubble Points vs.Pressures and CO,Compositions Based on Peng-Robinson Correlation 51 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Small Vessel Experiment This experiment is designed to determine the composition of the liquid portion of a vapor liquid equilibrated system.In order to isolate the liquid portion of the system,the sample must be taken from the bottom of the vessel.A system was designed with this purpose in mind and the unit shown in Figure 17 below. Pressure Gauge ---to GC -r 50mI Cylinder Liquid Phase coe Ice Water Bath Figure 17 Small Vessel Experiment Setup 52 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 The cylinder was filled with gas exiting the heat exchanger and then the cylinder was submerged vertically into an ice water bath with the pressure gauge above water level.As the gas cooled,a portion of the gas condensed into a liquid and gathered at the bottom the cylinder.The bottomwasconnectedto1/16"inch tubing that lead to the gas chromatograph where the liquid sample was analyzed for composition. The presence of a liquid phase inside the sample cylinder was distinguished by the gas chromatographic analysis,as there was a significant difference between the starting gas phase composition and the final gas phase composition of the system in the cases where there was condensation. For each run,the sample cylinder was filled with gas and an initial analysis of the gas was taken. The vessel was then submerged into an ice water bath where it was allowed to cool for at least 30 minutes.The valve located on the bottom of the sample cylinder was then opened to allow the liquid phase sample to travel to the gas chromatograph to be analyzed.After the analysis is complete,the pressure inside the cylinder is released so that another sample may be taken at a different pressure value.The process is then repeated at different pressures until no liquid phase may be achieved. Data Run 1 Starting Composition - Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |83.46859 |85.05612 |83.67514 |83.9613 |84.0402875 Argon 13.71958 |12.3842 |13.4486 |13.15694 13.17733 27 July 2008 - Initial Pressure -1375 Initial Temperature -80 Final Pressure -870 Final Temperature-9 Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide 95.44851 95.4774 95.61561 95.73106 |95.568145 Argon 3.37171 3.16831 3.19637 3.15763 3.223505 28 July 2008 - Initial Pressure -1025 Initial Temperature -23 Final Pressure -800 Final Temperature-10 53 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Trial 1 Trial 2 Trial 3 Average Carbon Dioxide |96.31592 |96.13819 |95.83456 |96.0962233 Argon 1.99569 |2.06692 |2.14367 2.06876 05 August 2008 - Initial Pressure -650 Initial Temperature -22 Final Pressure -600 Final Temperature-7 Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |88.36072 |88.0206 |88.12301 |88.36887 |88.16811 Argon 10.27235 |10.31007 |10.27509 |10.27199 |10.282375 54 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Final Gas Composition - Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |88.38772 |88.3073 |88.50735 |88.52971 88.43302 Argon 10.14155 |10.14312 |10.14313 |10.14907 |10.1442175 Notes As can be seen from the data,the liquid composition of the vapour liquid equilibrated system is distinctly different from that of the overall composition of the system.It can also be seen that at a liquid state does exist at both pressures of 870 and 800psi and temperatures of 9 and 10°C respectively but does not exist at a lower pressure of 600psi and a temperature of 7°c. Run 2 Data - Starting Composition - Trial 1 Trial 2 Trial 3 Average Carbon Dioxide 74.24185 74.07071 74.00295 74.10517 Argon 11.81779 11.91732 12.00136 |11.91215667 Nitrogen 14.15018 14.26 14.22462 14.2116 Sulfur Dioxide 0.4813 0.49518 0.49163 0.48937 18 August 2008 - Initial Pressure -850 Initial Temperature -23 Final Pressure -750 Final Temperature -9 Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |73.52727 73.91677 73.7084 73.77508 73.73188 Argon 12.16311 12.13681 12.10345 12.16288 |12.1415625 Nitrogen 14.35181 14.31585 14.29626 14.32416 14.32202 Sulfur Dioxide 0.49614 0.50655 0.50973 0.51268 0.506275 18 August 2008 - Initial Pressure -750 Initial Temperature -23 Final Pressure -690 Final Temperature -10.5 Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |68.07692 68.4489 68.4419 68.45859 |68.3565775 55 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Argon 14.82957 14.9077 14.68084 14.91454 |14.8331625 Nitrogen 17.47834 17.52955 17.52377 17.56148 17.523285 Sulfur Dioxide 0.689 0.59417 0.597 0.59969 0.619965 Final Gas Composition - Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |68.56309 68.401 68.53805 68.40833 |68.4776175 Argon 14.8921 14.85411 14.76574 14.75165 14.8159 Nitrogen 17.53611 17.49617 17.52005 17.54715 17.52487 Sulfur Dioxide 0.60585 0.60458 0.60583 0.60496 0.605305 Notes - As can be seen from the GC analysis,at this composition,no liquid state could be achieved. Run 3 Data - Starting Composition - Trial 1 Trial 2 Trial 3 Average Carbon Dioxide 72.6101 72.72745 72.63673 |72.65809333 Argon 12.37961 12.38764 12.50265 12.4233 Nitrogen 15.11773 15.07068 15.06717 |15.08519333 Sulfur Dioxide 0.4955 0.50175 0.50522 |0.500823333 19 August 2008 - Initial Pressure -850 Initial Temperature -23 Final Pressure -775 Final Temperature -9 Trial 1 Trial 2 Trial 3 Average Carbon Dioxide 73.87559 74.19011 73.78309 |73.94959667 Argon 11.84434 11.75869 11.88194 |11.82832333 Nitrogen 14.24126 14.3507 14.33437 |14.30877667 Sulfur Dioxide 0.48559 0.48084 0.48272 0.48305 Final Gas Composition - Trial 1 Trial 2 Trial 3 Average Carbon Dioxide 73.81936 74.09441 74.08196 |73.99857667 56 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 Argon 11.95299 11.86876 11.68538 11.83571 Nitrogen 14.29284 14.28503 14.26931 |14.28239333 Sulfur Dioxide 0.48143 0.49126 0.49198 |0.488223333 Notes - As with the previous run,no liquid state was achieved.This may be attributed to the high composition of the inert species in the system.The inert gases compose of over a quarter of the composition by mass of the system. Run 4 Data - Starting Composition - Trial 1 Trial 2 Trial 3 Average Carbon Dioxide 92.06266 91.58212 92.09044 91.91174 Argon 4.39712 4.46013 4.38982 4.41569 Nitrogen 5.12252 5.0095 4.85768 |4.996566667 Sulfur Dioxide 0.19213 0.19282 0.22088 |0.201943333 21 August 2008 -. Initial Pressure -850 Initial Temperature -23 Final Pressure -800 Final Temperature -9 Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |89.89933 89.89379 89.77933 90.02839 89.90021 Argon 5.08853 5.02972 5.09918 5.06462 |5.0705125 Nitrogen 5.8694 5.77133 5.85351 5.84141 5.8339125 Sulfur Dioxide 0.12327 0.1252 0.1237 0.12151 0.12342 Final Gas Composition - Trial 1 Trial 2 Trial 3 Trial 4 Average Carbon Dioxide |89.76122 89.96137 89.9332 90.10985 89.94141 Argon 5.04085 5.03903 5.02298 5.01807 |_5.0302325 Nitrogen 5.78458 5.77701 5.78137 5.73679 |5.7699375 Sulfur Dioxide 0.12436 0.12587 0.12607 0.12691 0.1258025 57 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008 REFERENCES -«noAlex G.Fassbender,United States Patent No:US 6,196,000 B1',March 6,2001. Office of Systems and Policy Support,Gilbert V.McGurl,Robert E.James,Edward L. Parsons,John A.Reuther,John G.Wimer,Quality Guidelines for Energy System Studies,'February 24,2004. .NETL,Increasing Security and Reducing Carbon Emissions of the U.S.Transportation Sector:A Transformational Role for Coal with Biomass,August 24,2007. Rentech,Review of Fischer-Tropsch Work by Rentech,October 10,1996. National Energy Technology Laboratory ,'Advanced Pulverized Coal Oxy-fuel Combustion',31"International Technical Conference on Coal Utilization &Fuel Systems,Clearwater,FL May 21 -25,Jared Ciferno. "Usibelli Coal Mine,Inc.',www.usibelli.com/specs.html,Healy Coal-Data Sheet. Ligang Zheng,Richard Pomalis and Bruce Clements,'Feasibility Study of ThermoEnergy Integrated Power System (TIPS)Process',March 2,2007. R.Allam,E.Foster and V.Stein,'Improving Gasification Economics through ITMOxygenIntegration',Proceeding of the 5"(IchemE)European gasification Conference, April 8-10,2002,Noordwijk,The Netherlands. 58 Interim Draft Report Fed Grant Number EM-833233301-0 August 22,2008