Enhancement of Fischer-Tropsch Process for Hydrocarbon Fuel Formulation in a GTL Environment

Abstract

An enhanced natural gas processing method using Fischer-Tropsch (FT) process for the synthesis of sulfur free, clean burning, hydrocarbon fuels, examples of which include syndiesel and aviation fuel. A selection of natural gas, separately or combined with portions of natural gas liquids and FT naphtha and FT vapours are destroyed in a syngas generator and used or recycled as feedstock to an Fischer-Tropsch (FT) reactor in order to enhance the production of syndiesel from the reactor. The process enhancement results are the maximum production of formulated syndiesel without the presence or formation of low value by-products.

1 . A method for producing synthetic hydrocarbons comprising:
 providing a hydrocarbon source consisting essentially of ethane, propane, butane, pentane, pentane plus or mixtures thereof to a syngas generator comprising steam methane reformer under conditions to produce a hydrogen-rich syngas stream; and   catalytically converting the hydrogen rich syngas stream in a Fischer-Tropsch reactor to produce synthetic hydrocarbons.   
     
     
         2 . The method of  claim 1 , wherein the hydrocarbon source is extracted from natural gas. 
     
     
         3 . The method of  claim 2 , wherein the extracted natural gas produces a gas phase consisting essentially of methane, and a liquid phase consisting essentially of ethane, propane, butane, pentane, pentane plus or mixtures thereof. 
     
     
         4 . The method of  claim 1 , wherein the hydrocarbon source consists essentially of ethane. 
     
     
         5 . The method of  claim 1 , wherein the hydrocarbon source consists essentially of propane. 
     
     
         6 . The method of  claim 1 , wherein the hydrocarbon source consists essentially of butane. 
     
     
         7 . The method of  claim 1 , wherein the hydrocarbon source consists essentially of pentane. 
     
     
         8 . The method of  claim 1 , wherein the hydrocarbon source consists essentially of pentane plus. 
     
     
         9 . The method of  claim 1 , further comprising a scrubbing unit to remove one or more components from the syngas stream. 
     
     
         10 . The method of  claim 9 , wherein the one or more components comprise one or more of ammonia, sulfur compounds, and carbon dioxide. 
     
     
         11 . The method of  claim 1 , wherein the hydrogen to carbon monoxide ratio is greater than 3:1. 
     
     
         12 . The method of  claim 1 , wherein the hydrocarbon source is provided to a combined steam methane reformer and an autothermal reformer. 
     
     
         13 . The method of  claim 1 , wherein the synthetic hydrocarbons produced comprise diesel fuel. 
     
     
         14 . The method of  claim 1 , wherein the synthetic hydrocarbons produced comprise jet fuel. 
     
     
         15 . The method of  claim 1 , wherein the synthetic hydrocarbons produced have an absence of sulfur. 
     
     
         16 . The method of  claim 1 , wherein the synthetic hydrocarbons produced have an increased cetane rating as compared to the cetane rating of petroleum based diesel. 
     
     
         17 . The method of  claim 1 , which is performed in a gas to liquid (GTL) plant. 
     
     
         18 . The method of  claim 1 , wherein said synthetic hydrocarbons contain at least naphtha; and
 said method further comprises recycling at least a portion of said naphtha to said steam methane reformer to form an enhanced hydrogen rich syngas stream; and re-circulating said enhanced hydrogen rich syngas stream for conversion to synthetic hydrocarbons.   
     
     
         19 . The method of  claim 1 , wherein said synthetic hydrocarbons contain at least naphtha and unconverted FT (Fischer-Tropsch) vapours; and said method further comprises recycling at least a portion of said naphtha and unconverted FT vapours to said syngas generator to form an enhanced hydrogen rich syngas stream; and re-circulating said enhanced hydrogen rich syngas stream for conversion to synthetic hydrocarbons. 
     
     
         20 . The method of  claim 1 , wherein the hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of greater than 2:1. 
     
     
         21 . The method of  claim 1 , wherein the hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of greater than 3:1. 
     
     
         22 . The method of  claim 1 , wherein the hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of approximately 2.5:1. 
     
     
         23 . The method of  claim 1 , wherein the hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of from 3:1 to 5:1. 
     
     
         24 . The method of  claim 1 , further comprising separating a portion of hydrogen from the syngas and feeding said portion to said SMR. 
     
     
         25 . A method for producing synthetic hydrocarbons comprising:
 providing a first hydrocarbon source consisting essentially of ethane, propane, butane, pentane, pentane plus or mixtures thereof;   providing a second hydrocarbon source comprising natural gas, methane, naphtha or combinations thereof;   providing both the first and second hydrocarbon sources to a syngas generator comprising steam methane reformer under conditions to produce an enhanced hydrogen-rich syngas stream, wherein the first and second hydrocarbon sources comprise no more than 80% methane; and   catalytically converting the enhanced hydrogen rich syngas stream in a Fischer-Tropsch reactor to produce synthetic hydrocarbons in a yield greater than that produced in the absence of the first hydrocarbon source.   
     
     
         26 . The method of  claim 25 , wherein the hydrocarbon source is extracted from natural gas. 
     
     
         27 . The method of  claim 26 , wherein the extracted natural gas produces a gas phase consisting essentially of methane, and a liquid phase consisting essentially of ethane, propane, butane, pentane, pentane plus or mixtures thereof. 
     
     
         28 . The method of  claim 25 , wherein the hydrocarbon source consists essentially of ethane. 
     
     
         29 . The method of  claim 25 , wherein the hydrocarbon source consists essentially of propane. 
     
     
         30 . The method of  claim 25 , wherein the hydrocarbon source consists essentially of butane. 
     
     
         31 . The method of  claim 25 , wherein the hydrocarbon source consists essentially of pentane. 
     
     
         32 . The method of  claim 25 , wherein the hydrocarbon source consists essentially of pentane plus. 
     
     
         33 . The method of  claim 25 , further comprising a scrubbing unit to remove one or more components from the syngas stream. 
     
     
         34 . The method of  claim 33 , wherein the one or more components comprise one or more of ammonia, sulfur compounds, and carbon dioxide. 
     
     
         35 . The method of  claim 25 , wherein the hydrogen to carbon monoxide ratio is greater than 3:1. 
     
     
         36 . The method of  claim 25 , wherein the hydrocarbon source is provided to a combined steam methane reformer and an autothermal reformer. 
     
     
         37 . The method of  claim 25 , wherein the synthetic hydrocarbons produced comprise diesel fuel. 
     
     
         38 . The method of  claim 25 , wherein the synthetic hydrocarbons produced comprise jet fuel. 
     
     
         39 . The method of  claim 25 , wherein the synthetic hydrocarbons produced have an absence of sulfur. 
     
     
         40 . The method of  claim 25 , wherein the synthetic hydrocarbons produced have an increased cetane rating as compared to the cetane rating of petroleum based diesel. 
     
     
         41 . The method of  claim 25 , which is performed in a gas to liquid (GTL) plant. 
     
     
         42 . The method of  claim 25 , wherein said synthetic hydrocarbons contain at least naphtha; and said method further comprises recycling at least a portion of said naphtha to said steam methane reformer to form an enhanced hydrogen rich syngas stream; and re-circulating said enhanced hydrogen rich syngas stream for conversion to synthetic hydrocarbons. 
     
     
         43 . The method of  claim 25 , wherein said synthetic hydrocarbons contain at least naphtha and unconverted FT (Fischer-Tropsch) vapours; and said method further comprises recycling at least a portion of said naphtha and unconverted FT vapours to said syngas generator to form an enhanced hydrogen rich syngas stream; and re-circulating said enhanced hydrogen rich stream for conversion to synthetic hydrocarbons. 
     
     
         44 . The method of  claim 25 , wherein the enhanced hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of greater than 2:1. 
     
     
         45 . The method of  claim 25 , wherein the enhanced hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of greater than 3:1. 
     
     
         46 . The method of  claim 25 , wherein the enhanced hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of approximately 2.5:1. 
     
     
         47 . The method of  claim 25 , wherein the enhanced hydrogen-rich syngas stream has a hydrogen to carbon monoxide ratio of from 3:1 to 5:1.