Process for producing hydrogen

Abstract

A process for producing hydrogen is provided. The process comprises the introduction of reactants into a reactor with a steam reforming section containing a steam reforming catalyst to form a hydrogen-containing product. The process is driven by heat generated in a combustion section containing an oxidation catalyst, which comprises a noble metal and boron nitride. According to the process of the subject invention, the first combustion reaction can rapidly generate heat and is advantageous for conducting steam reforming reactions.

1 . A process for producing hydrogen comprising a step of conducting a steam reforming reaction of reactants, wherein the steam reforming reaction is driven by a heat generated from a first combustion reaction, and the first combustion reaction comprises conducting an oxidation of a first fuel and is catalyzed by an oxidation catalyst comprising a noble metal and boron nitride.  
   
   
       2 . The process according to  claim 1 , wherein the noble metal is selected from a group consisting of Pt, Pd, Rh, Ru, and a combination thereof.  
   
   
       3 . The process according to  claim 1 , wherein the noble metal is Pt.  
   
   
       4 . The process according to  claim 1 , wherein the oxidation catalyst is carried by a support consisting essentially of a material selected from a group consisting of alumina, titania, zirconia, silica, and a combination thereof.  
   
   
       5 . The process according to  claim 4 , wherein the material is alumina.  
   
   
       6 . The process according to  claim 1 , wherein the first fuel comprises a hydrogen-containing gas, an alcohol, a hydrocarbon, or a combination thereof.  
   
   
       7 . The process according to  claim 6 , wherein the alcohol is selected from a group consisting of methanol, ethanol, propanol, isopropanol, butanol, and combinations thereof, and the hydrocarbon is selected from a group consisting of methane, ethane, propane, butane, pentane, hexane, gasoline, liquefied petroleum gas (LPG), and combinations thereof.  
   
   
       8 . The process according to  claim 6 , wherein the first fuel comprises a portion of a hydrogen-containing product and the hydrogen-containing product is produced by the steam reforming reaction.  
   
   
       9 . The process according to  claim 6 , wherein the first fuel comprises methanol.  
   
   
       10 . The process according to  claim 6 , further comprising conducting a second combustion reaction in a steam reforming section for conducting the steam reforming reaction until the steam reforming section reaches a desired temperature prior to the starting of the steam reforming reaction.  
   
   
       11 . The process according to  claim 10 , wherein the second combustion reaction comprises conducting an oxidization of a second fuel, wherein the second fuel is identical to or different from the first fuel.  
   
   
       12 . The process according to  claim 10 , wherein the first combustion reaction and the second combustion reaction are started simultaneously.  
   
   
       13 . The process according to  claim 1 , wherein the reactants comprise water as well as an alcohol, a hydrocarbon, or a combination thereof.  
   
   
       14 . The process according to  claim 13 , wherein the alcohol is selected from a group consisting of methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, and combinations thereof, and the hydrocarbon is selected from a group consisting of methane, hexane, liquefied petroleum gas (LPG), gasoline, naphtha oil, diesel oil, and combinations thereof.  
   
   
       15 . The process according to  claim 13 , wherein the reactants comprise water as well as methanol, hexane, or a combination thereof.  
   
   
       16 . The process according to  claim 1 , wherein the steam reforming reaction is catalyzed by a catalyst comprising Cu, Zn, Pd, Re, Ni, or a combination thereof.  
   
   
       17 . The process according to  claim 16 , wherein the steam reforming reaction is catalyzed by a catalyst comprising K as well as Cu, Zn, Pd, Re, Ni, or a combination thereof.  
   
   
       18 . The process according to  claim 1 , further comprising a step of purifying the product obtained from the steam reforming reaction to provide hydrogen with a relatively high purity and a spent product.  
   
   
       19 . The process according to  claim 18 , wherein the first fuel comprises a portion of the spent product.  
   
   
       20 . The process according to  claim 18 , wherein the purifying step is conducted with the use of at least one palladium membrane tube.  
   
   
       21 . The process according to  claim 20 , wherein the palladium membrane tube is formed by depositing a palladium-containing membrane on a porous support, and the porous support is made of stainless steel or a ceramic material.  
   
   
       22 . The process according to  claim 21 , wherein the palladium-containing membrane is made of palladium, a palladium-silver alloy or a palladium-copper alloy.  
   
   
       23 . The process according to  claim 20 , wherein the hydrogen obtained from the purifying step has a purity of at least 99%.  
   
   
       24 . The process according to  claim 18 , further comprising a converting step to convert any carbon-containing compounds contained in the hydrogen into alkane.  
   
   
       25 . The process according to  claim 20 , the process is conducted in a reactor comprising a steam reforming section, a combustion section, and a membrane tube section, the steam reforming reaction is carried out in the steam reform section, the first combustion reaction is carried out in the combustion section, and the purifying step is conducted in the membrane tube section, wherein the steam reforming section is arranged in the peripheral part of the reactor, the membrane tube section is arranged in the central part of the reactor and comprises at least one palladium membrane tube, and the combustion section is located between the membrane tube section and the steam reforming section.  
   
   
       26 . The process according to  claim 1 , wherein the reactants comprise water and methanol.  
   
   
       27 . The process according to  claim 26 , wherein the steam reforming reaction is conducted at a molar ratio of methanol/water ranging from about 1.0 to about 1.5.  
   
   
       28 . The process according to  claim 27 , wherein the molar ratio of methanol/water ranges from about 1.05 to about 1.25.  
   
   
       29 . The process according to  claim 26 , wherein the steam reforming reaction is conducted at a temperature ranging from about 200° C. to about 330° C.  
   
   
       30 . The process according to  claim 29 , wherein the steam reforming reaction is conducted at a temperature ranging from about 280° C. to about 300° C.  
   
   
       31 . The process according to  claim 20 , wherein the purifying step is conducted at a temperature of not higher than about 490° C.  
   
   
       32 . The process according to  claim 31 , wherein the purifying step is conducted at a temperature ranging from about 25° C. to about 490° C.  
   
   
       33 . The process according to  claim 31 , wherein the purifying step is conducted at a temperature ranging from about 200° C. to about 380° C.