Production of a mixture of hydrogen and natural gas

Abstract

The present subject matter relates to a process of reforming a natural gas stream by steam. The reforming is carried out at a temperature within a predetermined range to form a substantially carbon monoxide free product mixture of hydrogen and natural gas. The reforming is carried out in presence of a nickel-based catalyst. The temperature is controlled in a range of about 350° C. to about 390° C. The reforming can be started or stopped or its rate can be varied, based on an outflow demand of the product mixture of hydrogen and natural gas.

1 . A process comprising:
 reforming a natural gas stream by steam in presence of a nickel-based catalyst, wherein the reforming is carried out within a controlled temperature, range to form a product mixture of hydrogen and natural gas such that the product mixture is substantially free from carbon monoxide; and   removing excess steam from the product mixture.   
     
     
         2 . The process as claimed in  claim 1  comprising purifying the natural gas stream. 
     
     
         3 . The process as claimed in  claim 1 , wherein the reforming is carried out at a temperature in a range of about 350° C. to 390° C. 
     
     
         4 . The process as claimed in  claim 1 , wherein the reforming is carried out at a pressure in a range of about 5 bars to 7 bars. 
     
     
         5 . The process as claimed in  claim 1 , wherein the reforming is carried out at a gas hourly space velocity on dry basis in a range of about 1500 hr −1  to 2250 hr −1    
     
     
         6 . The process as claimed in  claim 1 , wherein the nickel-based catalyst comprises nickel, nickel oxide, magnesium oxide, and silica. 
     
     
         7 . The process as claimed in  claim 1  comprising preheating the natural gas stream by the product mixture. 
     
     
         8 . The process as claimed in  claim 1  comprising generating steam, wherein the generating the steam comprises:
 feeding a water stream to a firebox; 
 supplying a slip stream of the natural gas stream to the firebox; and 
 burning the slip stream of the natural gas in the firebox to heat the water stream to produce the steam. 
 
     
     
         9 . The process as claimed In  claim 8 , wherein the supplying the slip stream comprises controlling a flow rate of the slip stream based on a temperature in the reformer. 
     
     
         10 . The process as claimed in  claim 1 , wherein the process further comprises adjusting a composition of the product mixture by analysing the product mixture and supplying an additional quantity of natural gas to the product mixture to obtain a final product gas mixture having a predefined composition. 
     
     
         11 . The process as claimed in  claim 1 , wherein the process further comprises recycling a portion of the final product gas mixture based on an outflow demand of the product mixture. 
     
     
         12 . A plant ( 100 ) for production of a mixture of hydrogen and natural gas comprising:
 a heating unit ( 105 ) to heat water to produce steam;   a reformer ( 107 ) with a nickel-based catalyst bed disposed therein, to reform a natural gas stream by the steam to generate a mixture of hydrogen and natural gas, which is substantially carbon monoxide free;   a heat exchanger ( 102 ) to pre-heat the natural gas stream by the mixture; and   a condensing unit ( 110 ) to remove excess steam from the product mixture of hydrogen and natural gas.   
     
     
         13 . The plant ( 100 ) as claimed in  claim 12 , wherein the heating unit ( 105 ) is a firebox that is operated by burning a slipstream of the natural gas stream, and wherein the heating unit ( 105 ) also heats a portion of the natural gas stream to be reformed. 
     
     
         14 . The plant ( 100 ) as claimed in  claim 13  wherein the plant ( 100 ) further comprises a control valve ( 106 ) that controls a quantity of the natural gas in the slip stream, and wherein the control valve ( 106 ) is regulated by a temperature indicator controller ( 117 ) that senses the temperature in the reformer ( 107 ). 
     
     
         15 . The plant ( 100 ) as claimed in  claim 12 , wherein the reformer ( 107 ) is a fixed-bed vapour-phase down flow reformer. 
     
     
         16 . The plant ( 100 ) as claimed in  claim 12  comprising an impurity removal unit ( 103 ) with a hydrogen sulphide adsorbing substance disposed therein.