Options to reach Syngas Quality Requirements by Catalytic Reforming of Tars and Methane from FBgasification

Transcription

1 Options to reach Syngas Quality Requirements by Catalytic Reforming of Tars and Methane from FBgasification of Biomass 6 th International Freiberg Conference on IGCC & XtL Technologies Christian Hamel Fraunhofer UMSICHT Slide 1

2 Introduction Background Still high demand for gasification systems depending on a variety of factors Material utilization is desired Gas from allothermal steam gasification (e.g. FICFB Güssing) with good prerequisites for material utilization Difficulties with catalytic gas cleaning / tar reforming Lower process temperatures in comparison to other gasification systems result in low activities Few scientific insights available for monolithic catalysts in complex gas matrixes Allothermal FICFB gasifier in Güssing (AT ) Slide 2

3 Introduction Current research project at Fraunhofer UMSICHT Aim: Development of catalysts or catalytic process suitable for tar reforming / removal in sulfur-containing syngas at relatively low temperatures First step: Benchmark tests of a broad variety of different catalysts Bulk and monolith catalysts Nickel and precious metal (PM) catalysts Influence of different preparation routes Without and with H 2 S as severe catalyst poison Recent focus: Tests about influences of different precious metal amounts and components Tests with different catalyst type combinations Slide 3

4 Tests at Fraunhofer UMSICHT Overview Slide 4

5 Tests at Fraunhofer UMSICHT Synthetic Syngas Composition Gas composition typical for allothermal gasifiers Benzene and naphthalene taken as model tar substances H 2 S used to investigate possible catalyst poisoning 33,7% Ar CH4 25,9% 3,5% 1470 ppm 370 ppm CO CO2 H ppm H 2 S 7,0% H2O 14,0% 16,0% Benzol Naphthalin Slide 5

6 Tests at Fraunhofer UMSICHT Details about testing conditions Parameter Value Unit Reactor inner diameter (ID) 18 mm Catalyst length-to-diameter ratio (L / D) 2 - Volumetric flow rate at STP (Input) 2 L min Space velocity (GHSV) at STP 16,000 h -1 Steam-to-carbon ratio (S/C) Slide 6

7 Conversion Results Influence of 150 ppm H 2 S Conversions of a commercial nickel catalyst with and without 150 ppm H 2 S added The catalyst was applied as 3x3 mm pellets 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% % Gas temperature before catalyst [ C] Methane Methane - H2S Benzene Benzene - H2S Naphthalene Napththalene - H2S Slide 7

8 Relative change during reaction Relative change during reaction Results Relative changes in main gas composition H 2 S free results are shaded, results with H 2 S present are filled and calculated equilibriums are shown with black unfilled bars Both catalysts were applied as 3x3 mm pellets 15% Precious metal catalyst 15% Nickel catalyst 10% 5% 10% 5% CO CO2 0% 0% H2-5% -10% -5% -10% CH4 H2O -15% Gas temperature before catalyst [ C] -15% Gas temperature before catalyst [ C] Slide 8

9 Conversion Results Influence of different precious metal components Catalysts applied as monoliths No sulfur present 100% 90% 80% 70% 60% A Methane B Methane Cat. Mass ratio Molar ratio 50% C Methane D Methane PM1 PM2 PM1 PM2 40% A Benzene A B BenzeneB A % C Benzene C D Benzene D B 2 1 0,67 0,18 20% A Naphthalene C 1 2 0,33 0,35 B Naphthalene 10% C Naphthalene D ,53 D Naphthalene 0% Gas temperature before catalyst [ C] Slide 9

10 Conversion Results Influence of different precious metal components Catalysts applied as monoliths 150 ppm H 2 S added 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% A Methane B Methane C Methane D Methane A Benzene B Benzene C Benzene D Benzene A Naphthalene B Naphthalene C Naphthalene D Naphthalene Cat. Mass ratio Molar ratio PM1 PM2 PM1 PM2 A B 2 1 0,67 0,18 C 1 2 0,33 0,35 D ,53 0% % Gas temperature before catalyst [ C] Slide 10

11 Conversion Results Influence of PM components conversions at 800 C 150 ppm H 2 S added 100% 90% A B C D 80% 70% 60% 50% 40% 30% 20% 10% 0% Methane Benzene Naphthalene Cat. Mass ratio Molar ratio PM1 PM2 PM1 PM2 A B 2 1 0,67 0,18 C 1 2 0,33 0,35 D ,53 Slide 11

12 Summary & Outlook Overview of the project results Precious metal catalysts Depending on the PM combination, aromatic components can be almost completely converted in H 2 S free syngas down to temperatures of about 750 C Even with H 2 S present and at very high GHSV, high conversions for Naphthalene can be reached down to 800 C The effects of different PM ratios can be clearly seen especially with H 2 S present High absolute amount of PM atoms is not the most important factor for conversion Nickel catalysts Total removal of tars difficult even at high temperatures Reduction of temperature has relatively less effect on the reforming activity High impact of sulfur on the overall activity of the catalyst Slide 12

13 Summary & Outlook Outlook for the project Tests Continued experiments to assess the different mechanisms of reforming on PM catalysts Chemisorption Variation and gradual reduction of the test gas matrix Conduction of long-term tests Tests with combinations of different catalyst types E.g. sequential combination of Ni and PM based catalysts Preparation Development of a novel preparation technique for monolithic catalysts Study Economic feasibility and relevance of catalytic tar reforming systems Slide 13

14 FRAUNHOFER UMSICHT Chemical Energy Storage Department Thank you! Contact: Fraunhofer UMSICHT Osterfelder Straße Oberhausen Germany info@umsicht.fraunhofer.de Internet: Foto: photocase.de Dipl.-Ing. (FH) Christian Hamel Telefone: christian.hamel@umsicht.fraunhofer.de Slide 14