Mild hydrotreating/extraction process for low sulfur fuel for use in fuel cells

Abstract

A two step sulfur removal for treatment of hydrocarbonaceous fuel intended for use in a fuel cell comprising a mild hydrotreating step followed by an extraction step reduces the sulfur content in fuel to 5 ppm total sulfur or less and a fuel processor suitable for carrying out the process.

What is claimed is:  
     
         1 . A process for desulfurizing a hydrocarbonaceous fuel intended for use in a PEM fuel cell which comprises: 
 a) contacting a hydrocarbonaceous fuel containing sulfur with hydrogen in the presence of a hydrotreating catalyst at a temperature of between 300° F. and 500° F., a total pressure between 50 psig and 500 psig, and a space velocity between 0.5 hr −1  and 10 hr −1  for a time sufficient to convert up to 95% of the thiophenes present in the fuel, to produce a hydrotreated hydrocarbonaceous fuel;    b) contacting the hydrotreated hydrocarbonaceous fuel with a solid adsorbent or a liquid extractant selected to reduce the sulfur compounds remaining in the hydrotreated hydrocarbonaceous to 5.0 ppm or less;    c) recovering a hydrocarbonaceous fuel having a sufficiently reduced sulfur content wherein it is suitable for use as a fuel in a PEM fuel cell; and    d) supplying the hydrocarbonaceous fuel recovered in step (c) as fuel for a PEM fuel cell.    
     
     
         2 . The process of  claim 1  wherein the hydrocarbonaceous fuel is gasoline.  
     
     
         3 . The process of  claim 1  wherein the hydrocarbonaceous fuel contains methanol.  
     
     
         4 . The process of  claim 3  wherein the hydrocarbonaceous fuel is a mixture containing 10% or less by weight of methanol.  
     
     
         5 . The process according to  claim 2  to convert from 70% to 90% of the thiophenes present in the gasoline.  
     
     
         6 . The process according to  claim 2  wherein hydrotreating conditions include a reaction temperature between 350° F. and 475° F. and a total pressure between 100 psig and 400 psig.  
     
     
         7 . The process according to  claim 6  wherein the hydrotreating conditions include a space velocity between about 1.0 hr 1  and 4.0 hr −1  LHSV.  
     
     
         8 . The process according to  claim 2  to produce a gasoline which contains less than about 1 ppm sulfur.  
     
     
         9 . The process according to  claim 8  to produce a gasoline which contains less than about 0.5 ppm sulfur.  
     
     
         10 . The process according to  claim 9  to produce a gasoline which contains less than about 0.1 ppm sulfur.  
     
     
         11 . The process according to  claim 1  wherein the hydrotreating catalyst contains at least one of nickel and cobalt.  
     
     
         12 . The process according to  claim 1  wherein the hydrotreating catalyst contains at least one of molybdenum and tungsten.  
     
     
         13 . The process according to  claim 1  wherein the hydrotreating catalyst contains at least one of platinum and palladium.  
     
     
         14 . The process according to  claim 1  wherein the hydrotreating catalyst comprises nickel and molybdenum on an alumina support.  
     
     
         15 . The process according to claim wherein the solid adsorbent comprises at least one material selected from the group consisting of alumina, a zeolitic material, a clay material, activated carbon, copper, and metal oxides.  
     
     
         16 . The process of  claim 1  wherein the reduced sulfur fuel is intended for use in a stationary fuel cell.  
     
     
         17 . The process of  claim 1  wherein the reduced sulfur fuel is intended for use in a fuel cell.  
     
     
         18 . A mobile fuel processor suitable for desulfurizing a hydrocarbonaceous fuel intended for use in a PEM fuel cell used to power a transportation platform, said fuel processor comprising (a) hydrotreating zone suitable for contacting said hydrocarbonaceous fuel with hydrogen in the presence of a hydrotreating catalyst at a temperature of between 300° F. and 500° F., a total pressure of between 50 psig and 500 psig, a space velocity of between 0.5 hr −1  and 10 hr −1  for time sufficient to convert up to 95% of the thiophenes present in the fuel and (b) an adsorption zone containing a solid adsorbent or liquid extractant capable of reducing the total sulfur compounds present in the fuel leaving the hydrotreating zone to 5.0 ppm or less.  
     
     
         19 . The mobile fuel processor of  claim 17  wherein the hydrotreating zone and the adsorption zone are located in a single reaction chamber.  
     
     
         20 . The mobile fuel processor of  claim 17  wherein the hydrotreating zone and the adsorption zone are physically located in separate chambers from one another.