Joost van Bennekom 1, Daan Assink, Robbie Venderbosch, Erik Heeres 1 j.g.van.bennekom@rug.nl St. Petersburg 01-07-2010
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3 Introduction (1) Increasing biodiesel production Increasing crude glycerol production Overcapacity of glycerol New applications for glycerol Increasing methanol need and high interest in green methanol The GtM concept
Scope of the project 4 Vegetable oils Catalyst Biodiesel factory Biodiesel Methanol Crude glycerine Fuel gas GtM-Process Supermethanol Water Reforming glycerol + Methanol synthesis CO 2 Minerals + water
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6 Objectives (1) Glycerol syngas methanol Glycerol decomposition (products, no stoichiometry): C 3 H 8 O 3 - H 2 O + H 2 O liquid soluble products - H 2 O + H 2 O H 2 + CO + CO 2 + CH 4 + C 2 H 4 + C 2 H 6 + C 3 H 6 + C 3 H 8
7 Objectives (2) Main reaction in methanol synthesis: CO + 2H 2 CH 3 OH & CO + H 2 O CO 2 + H 2 To optimize methanol synthesis from glycerol a syngas with S n close to 2 is attractive How is the conversion related to the process conditions? What is the influence of a catalyst (alkali)? To what extent can the gas yield be steered?
8 Reforming in supercritical water (RSCW) 1 Supercritical water P > 221 bar and T > 374 ºC Rapid decomposition of biomass to gas Biomass with high moisture content can be treated Counter current heat exchange Gaseous products at high pressure 1 Kruse, A., J. Supercrit. Fluids, 2009. 47: p. 391-399.
9 Approach Feed: Glycerol and RME glycerol Conditions: 5 20 wt%, 500 700 ºC, 5 173 s Large pilot plant throughput 5 10 kg/hr Bench scale set-up throughput 1 kg/hr Different operating modes Water and gas are depressurized simultaneously In situ water/gas separation (HPS) Injection mode/premixed mode
Set-up for reforming in SCW 10
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12 Conversion vs. temperature Conditions: = 17-28 s, [feed] = 10.0 wt%
13 Conversion vs. feed concentration Conditions: T = 619 ºC, = 39 s
14 Conversion vs. residence time Conditions: T = 619 ºC, [feed] = 10.0 wt%
15 Summary conversion results Relations between process parameters and conversion were established Parameter Change Conv. (pure) Conv (crude) T (K) [feed] (wt%) (s) P (bar) The influence of alkali seems marginal on the conversion Next step is to investigate the gas yield
16 Investigating the tunability of the gas yield Numerous experiments were performed in different setups with different operating modes Gas yield depends on process conditions Is it possible to find a more general relation? What gas compositions can be obtained in glycerol reforming?
17 Stoichiometry of reforming (H 2 and CO)
18 Stoichiometry of reforming (CO 2 and CH 4 )
19 Stoichiometry of reforming (C 2 H 4 and C 2 H 6 )
20 Influence of the conversion on the gas yield (RME glycerol) Gas composition depends on the conversion Feed (%) H 2 * CO* CO 2 * CH 4 * C 2 H 4 * C 2 H 6 * S n (-) RME 50 1.0 0.6 0.4 0.3 0.02 0.08 0.65 RME 100 2.7 0.0 2.0 0.6 0.00 0.23 0.40 Pure 50 0.8 0.7 0.2 0.3 0.02 0.10 0.65 Pure 100 2.0 1.1 0.9 0.6 0.00 0.22 0.54 *mole component/mole feed Conditions => conversion => gas composition
21 Summarizing the influence of alkali In the presence of alkali Higher H 2 yield Higher CO 2 yield Lower CO yield CH 4, C 2 H 4, and C 2 H 6 is equal Alkali promote the water-gas shift reaction Alkali does not affect the overall reaction mechanism
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23 Overall conclusions Glycerol conversion is enhanced by temperature and residence time Glycerol conversion is nearly independent of feed concentration Alkali promote the conversion slightly but influences the gas composition significantly Gas composition can be estimated based on conversion Even in the presence of alkali significant CO yields can be obtained, but the conversion should be < 60 %
24 Thanks for your attention!
25 Summary gas yield results The gas yield can be correlated with the conversion Gas comp. 0% < < 30% 30% < < 60% 60% < < 100% H2 CO CO2 CH4 C2H4 C2H6 0 0 Pure glycerol Rme glycerol