High ethane recovery from a ryan/holmes additive recovery column

Abstract

A method for separating a high ethane-content product from a high methane-content feed stream including the steps of introducing a high methane-content feed stream into a first distillation column containing a plurality of vapor-liquid contact devices and generating a first bottoms stream, and introducing the first bottoms stream into a second distillation column containing a plurality of vapor-liquid contact devices and generating a second bottoms stream. Additional steps include recovering an additive stream from the second bottoms stream and injecting the additive stream into the first distillation column, and recovering a high ethane-content product from the second distillation column.

1 . A method for separating a high ethane-content product from a high methane-content feed stream comprising: 
 a. introducing said high methane-content feed stream into a first distillation column containing a plurality of vapor-liquid contact devices and generating a first bottoms stream;    b. introducing said first bottoms stream into a second distillation column containing a plurality of vapor-liquid contact devices and generating a second bottoms stream;    c. recovering an additive stream from said second bottoms stream and injecting said additive stream into said first distillation column; and    d. recovering a high ethane-content product from said second distillation column.    
     
     
         2 . The method of  claim 1  wherein said high ethane-content product is recovered from a position on said second distillation column which is above a point where said second bottoms stream is removed from said second distillation column and below a point where said first bottoms stream is introduced to said second distillation column.  
     
     
         3 . The method of  claim 1  wherein said additive stream comprises C 2 , C 3  and C 4 + hydrocarbons.  
     
     
         4 . The method of  claim 1  wherein said high ethane-content stream comprises predominantly C 2  and C 3  hydrocarbons.  
     
     
         5 . The method of  claim 1  further including the step of removing a methane product stream from said first distillation column.  
     
     
         6 . The method of  claim 5  wherein said high ethane-content product is blended with said methane product stream.  
     
     
         7 . A method for separating a high ethane-content product from a feed stream comprising: 
 a. introducing said feed stream into a first distillation column containing a plurality of vapor-liquid contact devices and generating a first bottoms stream;    b. introducing said first bottoms stream into a second distillation column containing a plurality of vapor-liquid contact devices and generating a second bottoms stream;    c. recovering additive from said second bottoms stream and injection of said additive into said first distillation column; and    d. recovering a high ethane-content product from said second distillation column, said high ethane-content product comprising: about 93 mole % C2 and C3 hydrocarbons with limited quantities of CO 2  or H 2 S or a combination of CO 2  and H 2 S.    e. treating said high ethane-content product to remove CO 2  and H 2 S.    
     
     
         8 . The method of  claim 7  wherein the feedstream comprises C 1 , C 2 , C 3  and C 4 + components.  
     
     
         9 . The method of  claim 1  further comprising the step of locating a high ethane-content product stream recovery point at a location optimizing ethane recovery and additive separation within said second distillation column.  
     
     
         10 . A method for separating a high ethane-content product from a feed stream including C 1 , C 2 , C 3  and C 4 + components, as well as CO 2  and/or H 2 S comprising: 
 a. introducing said feed stream into a first distillation column containing a plurality of vapor-liquid contact devices and generating a first bottoms stream;    b. introducing said first bottoms stream into a second distillation column containing a plurality of vapor-liquid contact devices and generating a second bottoms stream;    c. recovering an additive stream from said second bottoms stream and injecting said additive stream into said first distillation column; and    d. recovering a high ethane-content product from said second distillation column.    
     
     
         11 . A high ethane-content product comprising C 2 , C 3  and C 4 + hydrocarbons, said high ethane-content product manufactured by a process including the steps of: 
 a. introducing a high methane-content feed stream into a first distillation column containing a plurality of vapor-liquid contact devices and generating a first bottoms stream;    b. introducing said first bottoms stream into a second distillation column containing a plurality of vapor-liquid contact devices and generating a second bottoms stream;    c. recovering an additive stream from said second bottoms stream and injecting said additive stream into said first distillation column; and    d. recovering a high ethane-content product from said second distillation column.