Process for Producing Hydrogen

Patent metadata

Field	Value
Publication number	US-2016332876-A1
Application number	US-201514713351-A
Country	US
Kind code	A1
Filing date	May 15, 2015
Priority date	May 15, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

Process for producing hydrogen where multiple streams are heated in parallel with reformate that has passed from the shift reactor. Each of the multiple streams are heated from a temperature below the dew point of the reformate to a temperature above the dew point of the reformate by reformate that is cooled from a temperature above the dew point of the reformate to a temperature below the dew point of the reformate. The multiple streams can include two or more of water condensate, boiler feed water, hydrocarbon feedstock, and pressure swing adsorption unit by-product gas.

First claim

We claim:

1 . A process for producing a hydrogen product gas, the process comprising:
(a) withdrawing a reformate from a shift reactor, the reformate comprising H 2 O, H 2 , CO, and CO 2 ; (b) heating a water condensate by indirect heat transfer with the reformate from the shift reactor or a first divided portion thereof, the water condensate heated from a lower temperature, T WC,lower , to an upper temperature, T WC,upper , when being heated by the reformate or the first divided portion, and the reformate or first divided portion cooled from an upper temperature, T 1,upper , to a lower temperature, T 1,lower , when heating the water condensate; (c) heating boiler feed water by indirect heat transfer with the reformate from the shift reactor or a second divided portion thereof, the boiler feed water heated from a lower temperature, T BFW,lower , to an upper temperature, T BFW,upper , when being heated by the reformate or the second divided portion, and the reformate or second divided portion cooled from an upper temperature, T 2,upper , to a lower temperature, T 2,lower , when heating the boiler feed water; where T WC,lower , T BFW,lower , T 1,lower , and T 2,lower , are less than the dewpoint temperature of the reformate withdrawn from the shift reactor; and T WC,upper , T BFW,upper , T 1,upper , and T 2,upper , are greater than the dewpoint temperature of the reformate withdrawn from the shift reactor; (d) cooling a mixture comprising at least a portion of the reformate when the reformate heats the water condensate and the boiler feed water or comprising at least a portion of the first divided portion and at least a portion of the second divided portion when the first divided portion heats the water condensate and the second divided portion heats the boiler feed water, the mixture cooled in an amount effective to condense at least a portion of the water in the mixture to form condensed water and a water-depleted reformate gas; (e) separating the condensed water from the water-depleted reformate gas in a separator thereby forming the water condensate from at least a portion of the condensed water; (f) passing the water condensate from the separator to a first heat exchange section for the step of heating the water condensate by indirect heat transfer with the reformate or the first divided portion, and passing at least a portion of the water condensate from the first heat exchange section to a steam drum; and (g) separating a pressure swing adsorption unit feed comprising at least a portion of the water-depleted reformate gas in a pressure swing adsorption unit to form the hydrogen product gas and a pressure swing adsorption unit by-product gas.

2 . The process of 1 wherein the water condensate is heated by the first divided portion in the first heat exchange section and the boiler feed water is heated by the second divided portion in a second heat exchange section.

3 . The process of claim 1 , the process further comprising:
passing the reformate withdrawn from the shift reactor to a feedstock-heating heat exchanger to heat a hydrocarbon feedstock by indirect heat transfer with the reformate in the feedstock-heating heat exchanger and withdrawing the reformate from the feedstock-heating heat exchanger; wherein if the reformate from the shift reactor heats the water condensate in step (b) and the boiler feed water in step (c), the reformate from the shift reactor that heats the water condensate in step (b) and the boiler feed water in step (c) is the reformate withdrawn from the feedstock-heating heat exchanger; and wherein if the first divided portion of the reformate from the shift reactor heats the water condensate in step (b) and the second divided portion of the reformate from the shift reactor heats the boiler feed water in step (c), the first divided portion of the reformate from the shift reactor is a first divided portion of the reformate withdrawn from the feedstock-heating heat exchanger and the second divided portion of the reformate from the shift reactor is a second divided portion of the reformate withdrawn from the feedstock-heating heat exchanger.

4 . The process of claim 1 wherein the water condensate is heated by the first divided portion of the reformate from the shift reactor, the process further comprising:
heating a hydrocarbon feedstock by indirect heat transfer with the first divided portion, the hydrocarbon feedstock heated from a lower temperature, T HF,lower , to an upper temperature, T HF,upper when being heated by the first divided portion; where
T HF,lower is less than the dewpoint temperature of the reformate withdrawn from the shift reactor; and
T HF,upper , is greater than the dewpoint temperature of the reformate withdrawn from the shift reactor.

5 . The process of claim 1 wherein the boiler feed water is heated by the second divided portion of the reformate from the shift reactor, the process further comprising:
heating a hydrocarbon feedstock by indirect heat transfer with the second divided portion of the reformate from the shift reactor, the hydrocarbon feedstock heated from a lower temperature, T HF,lower , to an upper temperature, T HF,upper , when being heated by the second divided portion; where
T HF,lower is less than the dewpoint temperature of the reformate withdrawn from the shift reactor; and
T HF,upper is greater than the dewpoint temperature of the reformate withdrawn from the shift reactor.

6 . The process of claim 1 , the process further comprising:
(h) heating a hydrocarbon feedstock by indirect heat transfer with the reformate from the shift reactor or a divided portion of the reformate, the hydrocarbon feedstock heated from a lower temperature, T HF,lower , to an upper temperature, T HF,upper , when being heated by the reformate or the divided portion, and the reformate or divided portion cooled from an upper temperature, T 3,upper , to a lower temperature, T 3,lower , when heating the hydrocarbon feedstock; where T HF,lower and T 3,lower are less than the dewpoint temperature of the reformate withdrawn from the shift reactor; and T HF,upper and T 3,upper are greater than the dewpoint temperature of the reformate withdrawn from the shift reactor; wherein the mixture comprises at least a portion of the reformate when the reformate also heats the hydrocarbon feedstock or wherein the mixture further comprises at least a portion of the divided portion of the reformate that heats the hydrocarbon feedstock when the divided portion heats the hydrocarbon feedstock.

7 . The process of claim 6 wherein the hydrocarbon feedstock is heated by the divided portion in a third heat exchange section.

8 . The process of claim 6 , the process further comprising:
passing the reformate withdrawn from the shift reactor to a feedstock-heating heat exchanger to heat the hydrocarbon feedstock by indirect heat transfer with the reformate in the feedstock-heating heat exchanger and withdrawing the reformate from the feedstock-heating heat exchanger; wherein if the reformate from the shift reactor heats the water condensate in step (b), the boiler feed water in step (c), and the hydrocarbon feedstock in step (h), the reformate from the shift reactor that heats the water condensate in step (b), the boiler feed water in step (c), and the hydrocarbon feedstock in step (h) is the reformate withdrawn from the feedstock-heating heat exchanger; wherein if the first divided portion of the reformate from the shift reactor heats the water condensate in step (b), and the second divided portion of the reformate from the shift reactor heats the boiler feed water in step (c), and the divided portion of the reformate from the shift reactor heats the hydrocarbon feedstock in step (h), the first di

Assignees

• Air Prod & Chem

Inventors

• Xu Jianguo
• Peng Xiang-Dong

Classifications

• C01B2203/0283

  containing a CO-shift step, i.e. a water gas shift step · CPC title

• B01D53/047 Primary

  Pressure swing adsorption · CPC title

• C01B2203/042

  Purification by adsorption on solids · CPC title

• B01D2257/80

  Water · CPC title

• B01D2256/16

  Hydrogen · CPC title