Renewable energy integration with natural-gas based combined hydrogen and electricity production (CHEP) system and method
A method and a system for integrating renewable power with a natural gas hydrogen production plant are provided. An exemplary method include generating electricity and a reformed hydrogen stream in a solid oxide fuel cell (SOFC) stack, and providing the electricity to an electrolyzer to generate an electrolysis hydrogen stream. A second stream of electricity is generated in a renewable energy facility, when available, and providing the second stream of electricity to the electrolyzer to increase the generation of the electrolysis hydrogen stream.
1 . A method for integrating renewable power with a natural gas hydrogen production plant, comprising:
generating electricity and a reformed hydrogen stream in a solid oxide fuel cell (SOFC) stack;
providing the electricity from the SOFC stack to an electrolyzer to generate an electrolysis hydrogen stream;
generating a second stream of electricity in a renewable energy facility, when available;
providing the second stream of electricity to the electrolyzer to increase the generation of the electrolysis hydrogen stream;
when excess electricity from the second stream of electricity is available:
operating a portion of the SOFC stack as a solid oxide electrolytic cell (SOEC) stack;
providing the excess electricity from the second stream of electricity to the SOEC stack; and
generating hydrogen with the SOEC stack while a remainder of the SOFC stack continues to generate the reformed hydrogen stream and electricity.
2 . The method of claim 1 , comprising, when renewable energy is not available, providing the electricity from the SOFC to operate the electrolyzer to generate the electrolysis hydrogen stream.
3 . The method of claim 1 , comprising:
operating all of the SOFC stack as the SOEC stack;
providing the electricity from the second stream to power both the electrolyzer and the SOEC stack; and
generating the electrolysis hydrogen stream in both the electrolyzer and the SOEC stack, without generating electricity in the SOFC stack.
4 . The method of claim 1 , comprising providing steam from the SOFC stack to the SOEC stack.
5 . The method of claim 3 , comprising providing steam from a chemical plant or refinery to the SOEC stack.
6 . The method of claim 1 , comprising capturing carbon dioxide generated in the SOFC.
7 . The method of claim 6 , comprising providing the carbon dioxide as a product stream.
8 . The method of claim 6 , comprising using the carbon dioxide in enhanced oil recovery.
9 . The method of claim 1 , comprising providing an oxygen stream generated in the electrolyzer to the SOFC.
10 . The method of claim 1 , comprising providing a steam stream to the SOFC.
11 . The method of claim 1 , comprising providing a natural gas stream to the SOFC.
12 . The method of claim 1 , comprising:
separating carbon dioxide, by a carbon dioxide separator, from the reformed hydrogen stream; and
providing the reformed hydrogen stream, after separating the carbon dioxide, to a hydrogen tank fluidically coupled to the SOFC exhaust.
13 . An integrated hydrogen production system, comprising:
a solid oxide fuel cell (SOFC) configured to generate electricity and a reformed hydrogen stream, wherein a portion of the SOFC can be operated as a solid oxide electrolytic cell (SOEC);
an electrolyzer electrically coupled to a power line from the SOFC, wherein the electrolyzer is configured to receive the electricity from the SOFC to generate an electrolysis hydrogen stream;
a carbon dioxide capture system fluidically coupled to an exhaust line from the SOFC,
a steam source fluidically coupled to the SOFC;
a hydrocarbon source fluidically coupled to the SOFC to provide a gaseous hydrocarbon feed to the SOFC;
a renewable energy source, wherein the electrolyzer is coupled to a power line from the renewable energy source and the renewable energy source is configured to generate a second stream of electricity and provide the second stream of electricity to the electrolyzer to increase the generation of the electrolysis hydrogen stream;
a power line from the renewable energy source to the portion of the SOFC that can be operated as an SOEC;
wherein, the integrated hydrogen production system is configured to:
operate a portion of the SOFC as an SOEC when excess electricity from the second stream of electricity is available;
provide the excess electricity from the second stream of electricity to the SOEC; and
generate hydrogen with the SOEC while a remainder of the SOFC generates the reformed hydrogen stream and electricity.
14 . The integrated hydrogen production system of claim 13 , comprising an oxygen line from the electrolyzer to the SOFC.
15 . The integrated hydrogen production system of claim 13 , wherein the steam source comprises a refinery, chemical plant, or both.
16 . The integrated hydrogen production system of claim 13 , wherein the hydrocarbon source comprises a gas plant, and wherein the gaseous hydrocarbon feed comprises natural gas.
17 . The integrated hydrogen production system of claim 13 , comprising a pyrolysis unit, wherein the gaseous hydrocarbon feed comprises pyrolysis gas.
18 . The integrated hydrogen production system of claim 13 , comprising a water gas shift reactor, wherein the gaseous hydrocarbon feed comprises water gas.
19 . The integrated hydrogen production system of claim 13 , wherein the renewable energy source comprises a solar power plant.
20 . The integrated hydrogen production system of claim 13 , wherein the renewable energy source comprises a wind generation facility.
21 . The integrated hydrogen production system of claim 13 , further comprising:
a carbon dioxide separator fluidically coupled to the exhaust line of the SOFC and configured to separate hydrogen and carbon dioxide from the SOFC exhaust; and
a tank fluidically coupled to the SOFC exhaust and configured to receive hydrogen from the carbon dioxide separator.