A novel raw gas cooling system based on a CO conversion quench reactor

Transcription

1 A novel raw gas cooling system based on a CO conversion reactor K. Boblenz, M. Reinmöller, M. Bergmann, C. Wolfersdorf, S. Guhl, R. Pardemann, B. Meyer Institute of Energy Process Engineering & Chemical Engineering 14th June 20, Cologne, Germany

2 Outline Background and motivation o classic syngas production from coal o integrated CO conversion syngas production CO conversion reactor concept Modeling and results of simulation o CFD simulation o flowsheet simulation o thermochemical simulation Conclusions 2

3 Background and motivation Classic syngas production from coal (for chemical syntheses) oxygen fuel water-gas shift reaction: syngas module: entrained flow gasifier rawgas + slag CO 2 H 2 S water full water gas1 T=216 C 3 % CO conversion scrubber catal. CO conversion bypass gas CO 2 /H 2 S removal gas chemical product water+ slag (solid) advanced design forcing CO conversion 3

4 Background and motivation Integrated CO conversion syngasproduction oxygen fuel entrained flow gasifier raw gas + slag full water quech gas1 T=216 C scrubber catal. CO conversion CO 2 H 2 S CO 2 /H 2 S removal gas chemical product feed water (water bath) water+ slag (solid) HP steam HP water bypass gas 4

5 Background and motivation Integrated CO conversion syngasproduction oxygen fuel entrained flow gasifier feed water (water bath) raw gas + slag water+ slag (solid) MP steam CO full water conversion quech gas1 T=900 C steam generator HP steam HP water gas 2 T=260 C scrubber catal. CO conversion bypass gas CO 2 H 2 S CO 2 /H 2 S removal gas chemical product 5

6 Optimized design inlet CO conversion reactor concept steam injection steam injection o keep the high temperature level o next to syngas inlet outlets no built-in components o reduced slagging problems o optional water injection (below water line) residence time regulation o variable water bath fluid level water injection water bath [Boblenz, K.; Uebel, K.; Meyer, B.; Nikrityuk, P.; Förster, T.: Verfahren und Vorrichtung zur Teilkonvertierung von Rohgasen der Flugstromvergasung. German patent No. DE A1, 2015.] 6

7 CO conversion reactor CFD simulation Parameter study detailled modelling and simulation (GriMech 3.0) three raw gases variation of steam temperature and mass flow Results CO conversion rates up to 27 % characteristic CO conversion rate progression high gas outlet temperatures up to 1293 C H 2 /CO ratio in terms of total H 2 O/CO ratio [Uebel, K.; Rößger, P.; Prüfert, U.; Richter, A.; Meyer, B.: A new CO conversion reactor design. Fuel Processing Technology 148 (2016) ] 7

8 CO conversion reactor flowsheet simulation Example: reaction zone CFD result * ) model assumption flowsheet model (detail) D H eff s H reaction rate in kg H 2 /m³s reaction zone implementation in ASPENplus TM * ) [Uebel, K.; Rößger, P.; Prüfert, U.; Richter, A.; Meyer, B.: CFD-based multi-objective optimization of a reactor design.fuel Processing Technology. Volume 149, 1 August 2016, Pages ] 8

9 CO conversion reactor flowsheet simulation Model validation CFD results trend lines CFD results trend lines inaccurate reproduction of CO conversion decrease at high steam mass flows small differences between gas outlet temperatures of CFD and flowsheet gas A: dried lignite, 1450 C, 40 bar gas B: hard coal, 1650 C, 40 bar gas C: pyrolysed biomass, 1500 C, 30 bar 9

10 CO conversion reactor flowsheet simulation Results: process chain oxygen fuel entrained flow gasifier Factsage TM model catalytic CO conversion design size decrease: -8 % (Methanol) -3 % (SNG) steam (steam jacket) water (steam jacket) feed water (water bath) rawgas + slag water+ slag (solid) CO conversion water (under water injectors) gas1 T=900 C MP steam steam generator HP steam HP water gas 2 T=260 C scrubber catal. CO conversion bypass gas CO 2 H 2 S CO 2 /H 2 S removal bypass gas ratio increase: 44 % to 51 % (Methanol) 33 % to 38 % (SNG) gas chemical product 10

11 CO conversion reactor thermochemical simulation Results: fuel influence fuel alkali ash components (XRF analysis) dried lignite dried lignite + wood chips (49.1 wt.-%) dried lignite + sewage sludge (8.2 wt.-%) dried lignite + paper residue (2.6 wt.-%) Cl wt.-% K 2 O wt.-% Na 2 O wt.-% volatile alkali raw gas components (calculated) KCl bar 9.2 E E E E-04 KOH bar 1.8 E E E E-05 NaCl bar 3.4 E E E E-05 11

12 CO conversion reactor thermochemical simulation Results: alkali condensation while raw gas cooling minor alkali separation by CO conversion process main alkali sink: steam generator below 500 C heat exchanger less endangered 1 ppm cooling below 500 C by water injection 12

13 Conclusions validated flexible flowsheet modell for the new CO conversion design balancing results demonstrate benefits of the new design slight contribution of alkali species to gas phase alkali deposition in convective gas cooling system requires adjustment of outlet temperature 13

14 THANK YOU FOR YOUR ATTENTION! For enquiries or further questions, please contact: Dipl.-Ing. Kristin Boblenz Phone: Fax: Website: Acknowledgements: This work was funded by BMWi project HotVeGasII (FKZ G). Financial support of this study by BMWi and industrial partners is gratefully acknowledged. 14