Gasification and steam methane reforming integrated polygeneration method and system
This invention is a process and system for providing hydrogen at a high level of reliability from a gasification system by integrating it with SMR. Carbonaceous feedstock such as petroleum coke or coal or biomass is gasified to co-produce SNG, fuel gas, hydrogen, power and steam in conjunction with hydrogen production through steam methane reforming. Carbon dioxide may also be recovered in this process. The integrated schemes are designed in a way that maximizes the reliability of production of high value products such as hydrogen through gasification and minimizes the impact of high natural gas prices on hydrogen production by SMR.
1. A process for providing hydrogen at a high level of reliability from a gasification system comprising:
a) gasification of a carbonaceous material to form a synthesis gas;
b) dividing the synthesis gas into a first portion and a second portion; fueling an at least one gas turbine with the first portion of the synthesis gas and/or expanding steam in a steam turbine to generate electricity;
c) processing the second portion of synthesis gas to form a treated synthesis gas;
d) dividing the treated synthesis gas into two or more portions;
e) conversion of a first portion of the treated synthesis gas to synthetic natural gas; and
f) feeding at least a first portion of the synthetic natural gas to a steam methane reforming process to produce hydrogen, wherein the synthetic natural gas is mixed with a second portion of the treated synthesis gas;
wherein steps (a), (c), and (f) are exothermic reactions resulting in release of heat; and
g) recovering at least a portion of the heat released by the exothermic reactions to produce steam.
2. The process of claim 1 , wherein the process further comprises recovering hydrogen from a portion of the treated synthesis gas from step (e) by further processing in a shift reactor and a pressure swing adsorption unit.
3. The process of claim 1 , wherein the process further comprises recovering carbon dioxide from a waste gas stream produced in step (d) and/or from the feed to a pressure swing adsorption unit within the steam methane reforming process.
4. The process of claim 2 , wherein the process further comprises producing fuel gas by mixing a second portion of synthetic natural gas from step (f and a portion of treated synthesis gas from step (e).
5. The process of claim 1 , wherein the process further comprises recovering hydrogen from a portion of the treated synthesis gas from step (e) by feeding it to a shift reactor within a steam methane reforming process.
6. The process of claim 5 , wherein the process further comprises producing fuel gas by mixing a portion of synthetic natural gas from step (f) and a portion of treated synthesis gas from step (e).
7. The process of claim 6 , wherein the process further comprises recovering carbon dioxide from a waste gas stream produced in step (d) and/or from the feed to a pressure swing adsorption unit within the steam methane reforming process.
8. The process of claim 2 , wherein the process further comprises recovering carbon dioxide from a waste gas stream produced in step (d) and/or from the feed to a pressure swing adsorption unit within the steam methane reforming process.
9. The process of claim 4 , wherein the process further comprises recovering carbon dioxide from a waste gas stream produced in step (d) and/or from the feed to a pressure swing adsorption unit within the steam methane reforming process.
10. The process of claim 5 , wherein the process further comprises recovering carbon dioxide from a waste gas stream produced in step (d) and/or from the feed to a pressure swing adsorption unit within the steam methane reforming process.