Process for reforming hydrocarbons

Abstract

A process for the production of synthesis gas by the use of autothermal reforming in which tail gas from downstream Fischer-Tropsh synthesis is hydrogenated and then added to the autothermal reforming stage.

What is claimed is: 
     
         1 . Process for the production of liquid hydrocarbons from a hydrocarbon feedstock comprising:
 a) passing said hydrocarbon feedstock through an ATR, CPO or POx, and withdrawing a stream of hot effluent synthesis gas from the ATR, CPO or PDX,   b) converting the synthesis gas into liquid hydrocarbons via Fischer-Tropsch synthesis,   c) passing tail gas from the Fischer-Tropsch synthesis stage through a hydrogenation stage to produce a hydrogenated tail gas containing less than  1  mol olefins, and   d) adding the hydrogenated tail gas directly to said ATR, CPO or Pox;   e) optionally recovering the liquid hydrocarbons produced.   
     
     
         2 . Process according to  claim 1 , wherein said hydrocarbon feedstock is a gas that has passed through at least one adiabatic pre-reforming stage. 
     
     
         3 . Process according to  claim 1 , wherein said hydrocarbon feedstock is a gas that has passed through at least one steam reforming stage. 
     
     
         4 . Process according to  claim 1 , wherein said hydrocarbon feedstock is a gas mixture resulting from dividing a raw hydrocarbon feed gas into two streams, passing the first stream through at least one steam reforming stage to form a primary reformed gas, using the second stream as a by-pass stream to said steam reforming stage, and subsequently combining said primary reformed gas with the by-pass stream to form said hydrocarbon feedstock. 
     
     
         5 . Process according to  claim 1 , comprising dividing a raw hydrocarbon feed gas into two streams, by which one of the streams becomes said hydrocarbon feedstock, and passing the other stream through at least one steam reforming stage to form a reformed gas. 
     
     
         6 . Process according to  claim 3 , wherein the steam reforming stage is heat exchange reforming, and where at least a portion of the hot effluent synthesis gas from the ATR, CPO, or POx is used as heating medium in said heat exchange reforming. 
     
     
         7 . Process according to  claim 5 , wherein said hot effluent synthesis gas is combined with said reformed gas before, during or after said hot effluent synthesis gas has delivered heat to the heat exchange reforming. 
     
     
         8 . Process according to  claim 6 , comprising adding a stream comprising steam to said hot effluent synthesis gas, said reformed gas, or the combined stream of hot effluent synthesis gas and reformed gas. 
     
     
         9 . Process according to  claim 4 , wherein the, at least one adiabatic pre-reforming stage is conducted prior to dividing said raw hydrocarbon feed. 
     
     
         10 . Process according to  claim 1 , comprising mixing the hydrogenated tail gas with the hydrocarbon feedstock prior to conducting reforming in the ATR, CPO or POx. 
     
     
         11 . Process according to  claim 1 , comprising adding the hydrogenated tail gas to the ATR, CPO or POx as a separate stream. 
     
     
         12 . Process according to  claim 4 , comprising mixing the hydrogenated tail gas with said by-pass stream prior to conducting reforming in the ATR, CPO or POx. 
     
     
         13 . Process according to  claim 4 , comprising mixing the hydrogenated tail gas with said primary reformed gas. 
     
     
         14 . Process according to  claim 1 , wherein the hydrogenated tail gas of step c) contains below 0.5 mol %. 
     
     
         15 . Process according to  claim 1 , wherein the hydrogenated tail gas of step c) contains less than 0.2 mole %. 
     
     
         16 . Process according to  claim 1 , wherein the hydrogenated tail gas of step c) contains less than 0.1 mole %. 
     
     
         16 . Process according to  claim 1 , wherein the hydrogenated tail gas of step c) contains less than 0.1 mole %.