Conversion of biomass feedstocks into hydrocarbon liquid transportation fuels
Methods for converting a carbon-containing feedstock into a fluid transportation fuel are described. The methods may include converting the carbon-containing feedstock into a producer gas comprising H 2 , CO, CO 2 , and N 2 , and reacting the producer gas with a substrate catalyst to produce a combination of Fischer-Tropsch (F-T) products, the F-T products including the fluid transportation fuel. A portion of the F-T products may be catalytically cracked to produce additional amounts of the fluid transportation fuel. A portion of the F-T products may also be hydrogenated to produce additional amounts of the fluid transportation fuel. Apparatuses are also described or converting a carbon-containing feedstock into a fluid transportation fuel. The apparatuses may include a producer gas reactor, a Fischer-Tropsch reactor, a cracking reactor, and a hydrogenation reactor.
1. A method for converting a carbon-containing feedstock into a fluid transportation fuel, the method comprising:
converting the carbon-containing feedstock in the presence of air into a producer gas comprising H 2 , CO, CO 2 , and N 2 ;
delivering the producer gas to a Fischer-Tropsch (F-T) reactor without separating the N 2 from the producer gas;
reacting the producer gas with a substrate catalyst to produce a combination of F-T products, the F-T products including the fluid transportation fuel;
catalytically cracking a portion of the F-T products to produce additional amounts of the fluid transportation fuel wherein a temperature for reacting the producer gas with the substrate catalyst is about 250° C. to about 300° C.; and
hydrogenating a portion of the F-T products to produce additional amounts of the fluid transportation fuel.
2. The method of claim 1 , wherein the carbon-containing feedstock comprises biomass.
3. The method of claim 2 , wherein the biomass has a water content from about 5 wt. % to about 20 wt. %.
4. The method of claim 1 , wherein the carbon-containing feedstock comprises methane.
5. The method of claim 1 , wherein the fluid transportation fuel is selected from the group consisting of gasoline, diesel fuel, aviation fuel, and synthetic paraffinic kerosene.
6. The method of claim 1 , wherein the N 2 comprises about 50 mol. % of the producer gas.
7. The method of claim 1 , wherein the method further comprises increasing the ratio of H 2 :CO by having a portion of the producer gas undergo a water-gas-shift (WGS) reaction.
8. The method of claim 7 , wherein the WGS reaction is catalyzed by the substrate catalyst.
9. The method of claim 1 , wherein the F-T products are selected from the group consisting of methane, ethane, propanes, butanes, light olefins, gasoline, synthetic paraffinic kerosene, aviation fuel, diesel fuel, and waxes.
10. The method of claim 9 , wherein the light olefins comprise ethylene, propylene, or butelenes.
11. The method of claim 1 , wherein the step of catalytically cracking a portion of the F-T products comprises:
contacting the F-T products with a zeolite catalyst; and
splitting an F-T product constituent comprising a wax into two or more smaller hydrocarbons with the zeolite catalyst; and
aromatizing an F-T product constituent comprising a light olefin into an alkyl-aromatic compound.
12. The method of claim 11 , wherein the alkyl-aromatic compound is selected from the group consisting of a methyl-monocyclic aromatic and a ethyl-monocyclic aromatic.
13. The method of claim 1 , wherein the step of hydrogenating a portion of the F-T products comprises hydrogenating a hydrocarbon produced by the catalytic cracking step.
14. The method of claim 1 , wherein the step of hydrogenating a portion of the F-T products comprises flowing at least a portion of the F-T products through a fixed bed of a hydrogenation catalyst comprising palladium, platinum, or a combination of palladium and platinum.
15. The method of claim 14 , wherein the palladium hydrogenation catalyst comprises about 0.5 wt % palladium on an alumina substrate.
16. The method of claim 1 , wherein the step of hydrogenating a portion of the F-T products comprises exclusively supplying hydrogen for the hydrogenation from the producer gas.
17. The method of claim 1 , wherein the method further comprises cooling the substrate catalyst with a portion of the N 2 from the producer gas.
18. The method of claim 1 , wherein a pressure for reacting the producer gas with the substrate catalyst is about 250 psig or less.
19. A method for converting a carbon-containing feedstock into hydrocarbon waxes, the method comprising:
converting the carbon-containing feedstock in the presence of air into a producer gas comprising H 2 , CO, CO 2 , and N 2 ;
delivering the producer gas to a Fischer-Tropsch (F-T) reactor without separating the N 2 from the producer gas;
reacting the producer gas with a substrate catalyst to produce a combination of Fischer-Tropsch (F-T) products, the F-T products including hydrocarbon gases and liquids, and a first portion of the hydrocarbon waxes; and
reacting at least a portion of the hydrocarbon gases and liquids with the substrate catalyst to produce a second portion of the hydrocarbon waxes.