Systems and processes for producing ultrapure, high pressure hydrogen
View Patent ↗In various implementations, feed streams that include methane are reacted to produce synthesis gas. The synthesis gas may be further processed to produce ultrapure, high-pressure hydrogen streams.
1. A method for producing hydrogen, comprising;
exothermically reacting a first portion of a hydrocarbon feed stream with at least one of steam or an oxidant gas comprising molecular oxygen in a first reactor to produce an exothermically generated syngas product, wherein the feed stream includes methane;
endothermically reforming a second portion of the hydrocarbon feed stream with steam over a catalyst in a heat exchange reformer to produce an endothermically-reformed syngas product, wherein at least a portion of heat used in generation of the endothermically-reformed syngas product is obtained by recovering heat from the exothermically-generated syngas product;
wherein the endothermically-reformed syngas product is further processed as follows:
generating, at a pressure above 60 bar, a ratio of methane (CH 4 ) to hydrogen plus carbon monoxide (H 2 +CO) of above 5% molar in the endothermically-reformed syngas product from heat exchange reformer tubes;
separating at least the methane from a combination of the exothermically-generated syngas product and the endothermically-reformed syngas product as part of a waste-gas stream;
combusting at least a portion of the waste gas using exhaust from a gas turbine as an oxidant to produce superheated steam and hydrocarbon feed streams used in the exothermically and endothermically generated synthesis gas production; and
generating power using the gas turbine to power an oxygen production unit providing the oxygen for synthesis gas generation.
2. The method of claim 1 , wherein the exothermically-generated syngas product is generated using a partial oxidation burner followed by a catalytic section reforming section in an autothermal reformer.
3. The method of claim 1 , wherein the ratio of CH 4 to (H 2 +CO) in the endothermically generated synthesis gas from the heat exchange reformer tubes is between 5% and 10% molar.
4. The method of claim 1 , wherein the CO content of the synthesis gas is substantially reduced by catalytic reaction with steam in a shift conversion system generating H 2 and CO 2 .
5. The method of claim 1 , wherein substantially pure H 2 is separated from the syngas in a pressure swing adsorption system.
6. The method of claim 5 , wherein the CO 2 is separated from a shifted syngas prior to separation of the substantially pure H 2 .
7. The method of claim 1 , wherein the waste gas from a first H 2 PSA separator is compressed, heated, and mixed with steam, reducing CO content by catalytic reaction with water to produce additional H 2 .
8. The method of claim 7 , wherein the additional H 2 is separated in a second pressure swing adsorption system.
9. The method of claim 1 , wherein H 2 produced from two PSA units are at substantially a same pressure.
10. The method of claim 1 , wherein a total H 2 pressure is in a range from about 60 to about 200 bar.
11. The method of claim 1 , wherein a total H 2 pressure is in a range from about 70 bar to about 100 bar.
12. The method of claim 1 , wherein at least a portion of the waste gas from a second PSA is used as part of the fuel for the gas turbine.
13. The method of claim 1 , wherein at least a portion of the waste gas from a first PSA is used as part of the fuel for at least one of the gas turbine or a fired heater.
14. The method of claim 1 , wherein H 2 product streams are below 20 parts per million (ppm) by volume total impurity level.