Systems and processes for producing ultrapure, high pressure hydrogen

Abstract

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 last 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. 
     
     
         15 . A system for producing hydrogen, comprising;
 a PDX or an ATR that exothermically reacts 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;   a GHR that endothermically reforms 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;   a connector to direct the endothermically-reformed syngas product to a first module;   the first module that generates, 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;   a separator that separates the methane from a combination of the exothermically-generated syngas product and the endothermically-reformed syngas product to produce a waste-gas stream;   a heater that combusts at least a portion of the waste gas using exhaust from a gas turbine as an oxidant to produce superheating steam and hydrocarbon feed streams used in the exothermically- and endothermically-generated synthesis gas production; and   a generator that generates power using the gas turbine to power an oxygen production unit providing the oxygen for synthesis gas generation.   
     
     
         16 . The system of  claim 15 , wherein the exothermically-generated syngas product is generated using a catalytic section. 
     
     
         17 . The system of  claim 15 , 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. 
     
     
         18 . The system of  claim 15 , wherein CO content is substantially reduced by catalytic reaction with steam in a shift conversion system. 
     
     
         19 . The system of  claim 15 , wherein substantially pure H 2  is separated from the syngas in a pressure swing adsorption system. 
     
     
         20 . The system of  claim 19 , wherein the CO 2  is separated from a shifted syngas prior to separation of the substantially pure H 2 . 
     
     
         21 . The system of  claim 15 , 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 . 
     
     
         22 . The system of  claim 21 , wherein the additional H 2  is separated in a second pressure swing adsorption system. 
     
     
         23 . The system of  claim 15 , wherein H 2  produced from two PSA units are substantially a same pressure. 
     
     
         24 . The system of  claim 15 , wherein a total H 2  pressure is in a range from about 60 to about 200 bar. 
     
     
         25 . The system of  claim 15 , wherein a total H 2  pressure is in a range from about 70 bar to about 100 bar. 
     
     
         26 . The system of  claim 15 , wherein at least a portion of the waste gas from a second PSA is used as part of the fuel for the gas turbine. 
     
     
         27 . The system of  claim 15 , 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. 
     
     
         28 . The system of  claim 15 , wherein H 2  product streams are below 20 parts per million (ppm) by volume total impurity level. 
     
     
         29 . A system, comprising:
 a PDX or an ATR that exothermically reacts a first portion of a feed stream with steam and an oxidant gas comprising molecular oxygen in a first reactor to produce an exothermically-generated syngas product, wherein the feed stream includes methane;   a GHR that endothermically reforms a second portion of the 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 required in the generation of the endothermically-reformed syngas product is obtained by recovering heat from the exothermically-generated syngas product;   a connector to direct the endothermically-reformed syngas product to a high-temperature shift reactor;   the high-temperature shift reactor that endothermically reacts, at high temperature, carbon monoxide in a combination of the exothermically-generated syngas product and the heat exchange-reformed syngas product with steam to produce a first syngas, wherein the first syngas includes hydrogen and carbon monoxide from the high-temperature endothermic reaction;   a low-temperature shift reactor that endothermically reacts, at low temperature, carbon dioxide in the first syngas with steam to produce a second syngas with a carbon monoxide concentration of 1.25% or less;   a carbon dioxide adsorber that separates carbon dioxide from the second syngas to produce a carbon-dioxide stream;   a first solid adsorber that adsorbs contaminants from the second syngas to produce a hydrogen stream including ultra-pure hydrogen; and   a second solid adsorber that that adsorbs additional contaminants from the hydrogen stream to produce an ultra-pure hydrogen stream including less than 20 ppm of contaminants at a pressure of at least approximately 60 bars.