Autothermal reformer-reforming exchanger arrangement for hydrogen production
View Patent ↗Low-energy, low-capital hydrogen production is disclosed. A reforming exchanger 14 is placed in parallel with an autothermal reformer (ATR) 10 to which are supplied a preheated steam-hydrocarbon mixture. An air-steam mixture is supplied to the burner/mixer of the ATR 10 to obtain a syngas effluent at 650°-1050° C. The effluent from the ATR is used to heat the reforming exchanger, and combined reformer effluent is shift converted and separated into a mixed gas stream and a hydrogen-rich product stream. High capital cost equipment such as steam-methane reformer and air separation plant are not required.
1. A process for producing hydrogen, comprising:
catalytically reforming a first hydrocarbon portion with steam and excess air in an autothermal reactor to produce a first syngas effluent at a temperature from 650° to 1050° C.;
supplying the first syngas effluent to a reforming exchanger;
passing a second hydrocarbon portion with steam through a catalyst zone in the reforming exchanger to form a second syngas effluent;
discharging the second syngas effluent from the catalyst zone adjacent the inlet to form a syngas admixture with the first syngas effluent;
passing the admixture across the catalyst zone in indirect heat exchange therewith to cool the admixture and heat the catalyst zone;
collecting the cooled admixture from an outlet of the reforming exchanger;
shift converting the admixture to obtain a carbon dioxide-rich gas stream lean in carbon monoxide; and
separating the carbon dioxide-rich gas stream to form a hydrogen-lean, mixed gas stream comprising nitrogen and carbon dioxide and a hydrogen-rich product stream.
2. The process of claim 1 , wherein the mixed gas separation comprises membrane separation.
3. The process of claim 1 , wherein the mixed gas separation comprises pressure swing adsorption.
4. The process of claim 1 , wherein the catalyst zone comprises catalyst tubes, the process further comprising:
supplying the first syngas effluent to a shell-side of the reformer;
supplying the second hydrocarbon portion with steam through the catalyst tubes;
discharging the second syngas effluent from the catalyst tubes adjacent the shell-side inlet to form the syngas admixture.
5. The process of claim 1 wherein the carbon dioxide-rich gas stream from the shift conversion comprises a molar ratio of hydrogen to nitrogen less than 3.
6. The process of claim 1 wherein the mixed gas separation is free of cryogenic separation.
7. The process of claim 1 wherein the process is free of air separation.
8. The process of claim 1 wherein a proportion of the first hydrocarbon portion relative to a total of the first and second hydrocarbon portions is from 55 to 85 percent.
9. The process of claim 1 wherein a proportion of the first hydrocarbon portion relative to a total of the first and second hydrocarbon portions is from 60 to 80 percent.
10. The process of claim 1 wherein the hydrogen product stream has a purity of at least 70 volume percent.
11. The process of claim 10 , wherein the hydrogen product stream has a purity of from 90 to 99.5 volume percent.
12. The process of claim 1 , wherein the hydrogen product stream has a purity of at least 95 volume percent.
13. The process of claim 1 , wherein the hydrogen product stream has a purity of at least 97 volume percent.
14. The process of claim 1 , wherein the hydrogen product stream has a purity of at least 98.5 volume percent.
15. A process for generating an electrical current comprising the process of claim 1 and supplying the hydrogen-rich product stream to a fuel cell.
16. A hydrotreating process comprising the process of claim 1 and supplying the hydrogen-rich product stream to a hydrotreater.
17. The process of claim 1 , wherein the reforming, shift conversion and mixed gas separation comprise a process pressure from 10 to 200 bars.
18. The process of claim 17 , wherein the reforming, shift conversion and mixed gas separation comprise a process pressure of at least 30 bars.
19. The process of claim 1 , further comprising compressing air to the catalytic reforming with a gas turbine drive and recovering heat from exhaust from the gas turbine.