Process and system for producing biofuels with reduced carbon intensity
A process and/or system for producing one or more biofuels, wherein biogas (e.g., partially purified biogas produced by removing water, hydrogen sulfide and/or carbon dioxide from raw biogas) is transported by vehicle in one or mobile vessels. De-pressurization of the mobile vessels provides a change in pressure that can be used to provide work, cooling, and/or increased pressure for the production process. Combustion of the biogas produces heat and/or power used to reduce a carbon intensity of the biofuel or biofuel intermediate.
1 . A process for producing biofuel comprising:
(a) providing biogas from one or more biogas sources, said biogas comprising methane and provided in one or more mobile vessels, each mobile vessel pressurized to at least 2000 psig (13.79 MPa);
(b) removing and depressurizing biogas from each of the one or more mobile vessels;
(c) generating heat, power, or a combination thereof, by combusting a gas comprising methane from the biogas removed and depressurized from the one or more mobile vessels; and
(d) producing the biofuel or biofuel intermediate in a production process that includes treating a feedstock, said production process including the use of the heat, power, or a combination thereof, generated in step (c),
wherein a quantity of biogas used to produce the heat, power, or combination thereof used in step (d) is sufficient to reduce a carbon intensity of the biofuel or biofuel intermediate by at least 5 gCO2e/MJ, and
wherein a change in pressure provided by the depressurizing in step (b) is used to provide work for the production process, cooling for the production process, increased pressure for the production process, or a combination thereof.
2 . The process according to claim 1 , wherein the biofuel or biofuel intermediate produced in step (d) is ethanol, and wherein the production process comprises:
(i) treating the feedstock to produce one or more sugars;
(ii) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol; and
(iii) recovering the ethanol.
3 . The process according to claim 2 , wherein recovering the ethanol comprises a distillation.
4 . The process according to claim 2 , wherein said feedstock is corn grain, and wherein treating the feedstock to produce one or more sugars comprises milling the feedstock and adding amylase enzyme to the milled feedstock to hydrolyze starch therein.
5 . The process according to claim 4 , wherein the production process produces distiller's dried grain or distiller's dried grain with solubles.
6 . The process according to claim 5 , wherein the change in pressure produces cooled biogas, said cooled biogas used to cool distiller's dried grains or distiller's dried grain with solubles.
7 . The process according to claim 2 , wherein the feedstock comprises a lignocellulosic feedstock, and wherein treating the feedstock to produce one or more sugars comprises pretreating the feedstock at an elevated temperature to produce a pretreated slurry, and adding cellulase enzyme to the pretreated slurry to hydrolyze cellulose therein.
8 . The process according to claim 1 , wherein a change in pressure provided by the depressurizing in step (b) is used to provide cooling for the production process.
9 . The process according to claim 8 , wherein the change in pressure produces cooled biogas, said cooled biogas used to cool a circulating fluid directed to a condenser.
10 . The process according to claim 1 , wherein a change in pressure provided by the depressurizing in step (b) is used to provide work for the production process, wherein providing said work comprises passing the biogas removed from the one or more mobile vessels through a turboexpander.
11 . The process according to claim 1 , wherein the depressurizing in step (b) is conducted so as to provide the biogas at a pressure of at least 150 psig (1.03 MPa) for further processing.
12 . The process according to claim 11 , wherein the biogas at a pressure of at least 150 psig (1.03 MPa) is provided to a biogas upgrading unit comprising a membrane unit or a scrubbing unit without a substantial reduction in pressure, said membrane unit or scrubbing unit configured to remove carbon dioxide.
13 . The process according to claim 1 , wherein the biogas in the one or more mobile vessels is raw biogas or partially purified biogas, wherein the process includes upgrading the raw or partially purified biogas removed in step (b) prior to generating heat, power, or a combination thereof, in step (c), and wherein the process comprises collecting carbon dioxide produced from the upgrading and providing the collected carbon dioxide as part of a carbon capture, usage, and storage approach to reduce a carbon intensity of the biofuel.
14 . The process according to claim 1 , wherein the process is an integrated process that produces ethanol and renewable natural gas, and wherein there is heat exchanged between the ethanol production process and the renewable natural gas production process.
15 . The process according to claim 1 , wherein the biogas used in step (c) has a carbon intensity that does not exceed −100 gCO2e/MJ and is produced from manure.
16 . The process according to claim 1 , wherein the biogas provides more than 25% of the methane used for generating heat, power, or a combination thereof within the fuel production process.
17 . The process according to claim 1 , wherein the process comprises using at least 3000 MMBtu/day of manure derived biogas.
18 . The process according to claim 1 , wherein the biogas is derived from swine manure or dairy manure.
19 . A process for producing one or more biofuels comprising:
(a) treating a feedstock to produce one or more sugars;
(b) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol;
(c) recovering the ethanol;
(d) removing and depressurizing biogas from one or more mobile vessels pressurized to at least 2000 psig (13.79 MPa), said removed and depressurized biogas comprising methane;
(e) generating heat, power, or a combination thereof from at least a portion of the methane; and
(f) using the heat, power, or combination thereof in step (a), step (b), step (c), or a combination thereof, thereby reducing a carbon intensity of the ethanol,
wherein depressurizing the biogas in step (d) is conducted so as to provide work for step (a), step (b), step (c), or a combination thereof,
cooling for step (a), step (b), step (c), or a combination thereof, or any combination thereof.
20 . A process for producing one or more biofuels comprising:
(a) treating a feedstock to produce one or more sugars;
(b) adding a fermentation organism to a mixture comprising the one or more sugars and fermenting the one or more sugars to produce ethanol;
(c) recovering the ethanol;
(d) removing and depressurizing biogas from one or more mobile vessels having a pressure of at least 2000 psig (13.79 MPa), said removed and depressurized biogas comprising methane;
(e) generating heat, power, or a combination thereof from at least some of the methane; and
(f) using the heat, power, or combination thereof in step (a), step (b), step (c), or a combination thereof, thereby reducing a carbon intensity of the ethanol,
wherein said depressurizing comprises providing a pressure drop that cools the removed biogas, and wherein the process comprises providing heat transfer between the cooled biogas and a heat transfer medium and providing cooling for the process with the heat transfer medium.