Treatment of natural gas having methane and nitrogen, comprises withdrawing nitrogen from the natural gas to obtain a natural gas depleted in nitrogen and a nitrogen rich stream, and transforming a part of depleted natural gas

摘要

#CMT# #/CMT# The process for treating a natural gas having methane and nitrogen, comprises withdrawing the nitrogen from the natural gas to obtain a natural gas depleted in nitrogen and a nitrogen rich stream, transforming a part of nitrogen depleted natural gas to obtain a first gaseous mixture by vapor-reforming reaction in presence of water, reacting the first gaseous mixture with methanol to produce an effluent, and contacting the nitrogen rich stream with a hydrogen rich stream to produce a second gaseous mixture. The effluent is separated in a methanol rich stream and the hydrogen rich stream. #CMT# : #/CMT# The process for treating a natural gas having methane and nitrogen, comprises withdrawing the nitrogen from the natural gas to obtain a natural gas depleted in nitrogen and a nitrogen rich stream, transforming a part of nitrogen depleted natural gas to obtain a first gaseous mixture by vapor-reforming reaction in presence of water, reacting the first gaseous mixture with methanol to produce an effluent, and contacting the nitrogen rich stream with a hydrogen rich stream to produce a second gaseous mixture. The effluent is separated in a methanol rich stream and the hydrogen rich stream. The second gaseous mixture is purified to obtain an ammonia rich stream. The first gaseous mixture has hydrogen to carbon monoxide molar ratio of 3-4 moles/mole. The vapor-reforming reaction is adjusted so that a part of methane is not consumed. The traces of carbon monoxide and carbon dioxide are reacted with hydrogen in the contacting step to eliminate the traces. The transformation of part of nitrogen depleted natural gas is operated at a pressure and temperature of 5-60 bars and 500-1000 deg C. The reacting step is operated at a pressure and temperature of 30-150 bars and 100-400 deg C. The contacting step is operated at a pressure of 5-150 bars and at a temperature of 100-500 deg C. The natural gas is deacidified to obtain a deacidified natural gas and a carbon dioxide rich stream. Contacting 2-4 moles of ammonia with 1 mole of carbon dioxide to produce carbamate by a chemical reaction at a pressure and a temperature of 100-250 bars and 100-250 deg C, and chemically decomposing the carbamate to produce urea at a pressure of 2-20 bars. #CMT#USE : #/CMT# The process is useful for treating a natural gas having methane and nitrogen (claimed), with enhancement in the nitrogen and carbon dioxide for producing formic ester and ammonia or urea. #CMT#ADVANTAGE : #/CMT# The process improves the extraction profitability of natural gas thus enhancing the transformation of all or a part of molecular nitrogen content in the natural gas. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The figure shows a first mode of production of above process with the production of ammonia. 1 : Conveying the natural gas to a deacidification unit having the chemical solvents 2 : Conveying the solvent to a regeneration unit 3 : Converting hydrogen sulfide into sulfur 4 : Evacuation of carbon dioxide 5 : Regenerating the solvent. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Components: The first gaseous mixture comprises carbon monoxide, hydrogen and methane. The effluent comprises formic ester and hydrogen. The second gaseous mixture comprises ammonia. The hydrogen rich stream comprises methane, traces of carbon monoxide and carbon dioxide.