Process for the production of synthesis gas

Abstract

A process for the production of synthesis gas for obtaining compounds such as ammonia or methanol, in which hydrocarbons and steam are reacted first in a primary reforming section ( 11 ) and then—together with oxygen—in a secondary reforming section ( 12 ), thus obtaining CO, CO 2 , H 2 and possibly N 2 which are then fed to a carbon monoxide conversion section ( 13, 14 ), is distinguished by the fact of reacting hydrocarbons, steam and oxygen in an autothermal reforming section ( 20 ) provided in parallel with respect to other reforming sections ( 11, 12 ), and feeding the so produced CO, CO 2 , H 2 and possibly N 2 to the carbon monoxide conversion section ( 13, 14 ).

1 . Process for the production of synthesis gas for obtaining compounds such as ammonia or methanol, comprising the steps of: 
 feeding a first flow comprising hydrocarbons and a first gas flow comprising steam to a primary reforming section;    feeding a first gas flow comprising oxygen and possibly nitrogen to a secondary reforming section;    reacting said hydrocarbons and said steam first in the primary reforming section and then—together with said oxygen—in the secondary reforming section, obtaining a first gas phase comprising CO, CO 2 , H 2  and possibly N 2 ;    feeding said first gas phase comprising CO, CO 2 , H 2  and possibly N 2  to a carbon monoxide conversion section;    characterised in that it further comprises the steps of:    feeding a second flow comprising hydrocarbons, a second gas flow comprising steam and a second gas flow comprising oxygen and possibly nitrogen to an autothermal reforming section arranged in parallel with respect to said primary and secondary reforming sections;    reacting said hydrocarbons, said steam and said oxygen in said autothermal reforming section, obtaining a second gas phase comprising CO, CO 2 , H 2  and possibly N 2 ;    
       feeding said second gas phase comprising CO, CO 2 , H 2  and possibly N 2  to said carbon monoxide conversion section.  
     
     
         2 . Process according to    claim 1   , characterised in that said second gas flow comprising oxygen comprises oxygen enriched air.  
     
     
         3 . Process according to    claim 1   , characterised in that it further comprises the step of subjecting at least a part of said second gas flow comprising hydrocarbons and said second gas flow comprising steam to a pre-reforming treatment before being fed to said autothermal reforming section.  
     
     
         4 . Process according to    claim 1   , characterised in that it further comprises the step of feeding a portion of said first flow comprising hydrocarbons to said autothermal reforming section.  
     
     
         5 . Plant for producing synthesis gas for obtaining compounds such as ammonia or methanol, comprising: 
 a primary reforming section ( 11 ) and secondary reforming section ( 12 ) arranged in series for obtaining a first gas phase comprising CO, CO 2 , H 2  and possibly N 2 ;    respective means ( 1 ,  2 ) for feeding a first flow comprising hydrocarbons and a first gas flow comprising steam to said primary reforming section ( 11 );    means ( 3 ) for feeding a first gas flow comprising oxygen and possibly nitrogen to said secondary reforming section ( 12 );    means ( 1 ) for feeding said first gas phase comprising CO, CO 2 , H 2  and possibly N 2  to a carbon monoxide conversion section ( 13 ,  14 );    characterised in that it comprises:    an autothermal reforming section ( 20 ) for obtaining a second gas phase comprising CO, CO 2 , H 2  and possibly N 2  ;    respective means ( 5 - 7 ) for feeding a second flow comprising hydrocarbons, a second gas flow comprising steam and a second gas flow comprising oxygen and possibly nitrogen to said autothermal reforming section ( 20 );    means ( 5 ) for feeding said second gas phase comprising Co, CO 2 , H 2  and possibly N 2  to said carbon monoxide conversion section ( 13 ,  14 ).    
     
     
         6 . Plant according to the    claim 5   , characterised in that it further comprises: 
 a pre-reforming section ( 19 );    means ( 5 ) for feeding at least a part of said second gas flow comprising hydrocarbons and said second gas flow comprising steam to said pre-reforming section ( 19 );    means ( 5 ) for connecting said pre-reforming section ( 19 ) with said autothermal reforming section ( 20 ).    
     
     
         7 . Plant according to    claim 5   , characterised in that it further comprises means ( 8 ) for feeding a portion of said first flow comprising hydrocarbons to said autothermal reforming section ( 20 ).  
     
     
         8 . Method of retrofitting a plant for the production of synthesis gas for obtaining compounds such as ammonia or methanol, of the type comprising a primary reforming section ( 11 ) and a secondary reforming section ( 12 ) provided in series for obtaining a first gas phase comprising CO, CO 2 , H 2  and possibly N 2 , respective means ( 1 ,  2 ) for feeding a first flow comprising hydrocarbons and a first gas flow comprising steam to said primary reforming section ( 11 ), means ( 3 ) for feeding a first gas flow comprising oxygen and possibly nitrogen to said secondary reforming section ( 12 ), means ( 1 ) for feeding said first gas phase comprising CO, CO 2 , H 2  and possibly N 2  to a carbon monoxide conversion section ( 13 ,  14 ), said method comprising the steps of: 
 providing an autothermal reforming section ( 20 ) for obtaining a second gas phase comprising CO, CO 2 , H 2  and possibly N 2 ;    providing respective means ( 5 - 7 ) for feeding a second flow comprising hydrocarbons, a second gas flow comprising steam and a second gas flow comprising oxygen and possibly nitrogen to said autothermal reforming section ( 20 );    providing means ( 5 ) for feeding said second gas phase comprising CO, CO 2 , H 2  and possibly N 2  to said carbon monoxide conversion section ( 13 ,  14 ).    
     
     
         9 . Method according to    claim 8   , characterised in that it further comprises the steps of: 
 providing a pre-reforming section ( 19 );    providing means ( 5 ) for feeding at least a part of said second flow comprising hydrocarbons and said second gas flow comprising steam to said pre-reforming section ( 19 );    providing means ( 5 ) for connecting said pre-reforming section ( 19 ) with said autothermal reforming section ( 20 ).    
     
     
         10 . Method according to    claim 8   , characterised in that it further comprises the steps of: 
 providing means ( 8 ) for feeding a portion of said first flow comprising hydrocarbons, and possibly a portion of said first gas flow comprising steam, to said autothermal reforming section ( 20 ).