Sales Gas Enrichment with Propane and Butanes By IDS Process

Abstract

The present invention is a separation unit process in which a high pressure section of a separation unit operates at a relatively high pressure to initially process and separate a high pressure feed stream and a low pressure section of the separation unit to initially process and separate a low pressure feed stream, where the high pressure section and the low pressure section are integral with and exchange streams to accomplish a desired separation of a wellhead fluid feed which typically includes a heavier portion of pentanes and heavier components

What is claimed is: 
     
         1 . A separation unit process for a hydrocarbon fluid feed from a wellhead source comprising:
 (a) separating the fluid feed in a high pressure drum to form an HP gas and an HP liquid;   (b) reducing the pressure of the HP liquid to a low pressure and separating the low pressure HP liquid in a stabilizer column to form a sales oil product as a bottoms liquid product and a stabilizer overhead stream, which has hydrocarbon components that consist essentially of butanes and lighter components;   (c) combining a compressed stabilizer overhead stream with the HP gas to be fed to a high pressure column operating at about the pressure of the natural HP gas feed, where a portion of a liquid bottoms stream of the high pressure column consists of a sales condensate stream recovering a portion of all hydrocarbon components of pentanes and heavier components in the fluid feed and a high pressure column overhead stream is compressed in a first compressor, where a portion of the compressed high pressure column overhead is further compressed to form a sale gas stream;   (d) the balance of the compressed high pressure column overhead stream being cooled and fed to the bottom stage of an fuel gas absorber column operating at a substantially higher pressure than the high pressure column, where the fuel gas absorber column overhead stream is mixed with the balance of the liquid bottom stream of the high pressure column (pentanes plus), cooled and separated to form a fuel gas stream and an absorber liquid stream, which is fed to the top stage of the fuel absorber column; and   (e) a fuel gas absorber liquid bottoms stream is fed to the high pressure column.   
     
     
         2 . The process of  claim 1  wherein the sales gas product comprises 70 percent or more of the propane and butanes in the fluid feed. 
     
     
         3 . The process of  claim 2  wherein the sales gas product meets specifications for a transportation pipeline in which the sales gas product is transported from a wellhead area. 
     
     
         4 . The process of  claim 3  wherein the sales gas product consists of essentially all propane and butanes present in the fluid feed that for dewpoint specification requirements could not be separated into the sales gas product. 
     
     
         5 . The process of  claim 4  wherein the hydrocarbon portion of the condensate product comprises essentially only pentanes and heavier components. 
     
     
         6 . The process of  claim 4  wherein the hydrocarbon portion of the condensate product and stabilized oil product contain essentially all pentanes and heavier from the fluid feed. 
     
     
         7 . A separation unit process for a hydrocarbon fluid feed from a wellhead source comprising:
 (a) separating the hydrocarbon fluid feed in a high pressure drum to form an HP gas and an HP liquid;   (b) reducing the pressure of the separated HP liquid to a low pressure and separating the low pressure HP liquid in a stabilizer column to form a stabilizer bottom stream, a portion of which is separated as a stabilized oil product, and a stabilizer overhead stream which has hydrocarbon components that consist essentially of pentanes and lighter components;   (c) a first stabilizer overhead stream is compressed, cooled and separated to form a liquid reflux stream, fed to a first stage of the stabilizer column, and a second stabilizer overhead stream;   (d) a portion of the second stabilizer overhead stream is cooled and fed to a first stage of a high pressure absorber operating at about the same pressure as the natural gas feed;   (e) HP gas being cooled and fed to a bottom stage of the high pressure absorber, where the high pressure absorber overhead stream is mixed with the balance of the second overhead stabilizer stream, to form a mixed stream, where a portion of the mixed stream is further compressed to form a sale gas stream;   (f) a high pressure absorber bottoms stream being fed to the stabilizer column;   (g) the balance of the compressed mixed stream being cooled and fed to the bottom stage of an fuel absorber column operating at a substantially higher pressure than the high pressure column, where the fuel absorber column overhead stream is mixed with the balance of the liquid bottom stream of the high pressure column, cooled and separated to form a fuel gas stream and an absorber liquid stream, which is fed to the top stage of the fuel absorber column; and   (h) a fuel absorber liquid bottoms stream is fed to the high pressure column.   
     
     
         8 . The process of  claim 7  wherein the sales gas product comprises 70 percent or more of the propane and butanes in the fluid feed. 
     
     
         9 . The process of  claim 8  wherein the sales gas product meets specifications for a transportation pipeline in which the sales gas product is transported from a wellhead area. 
     
     
         10 . The process of  claim 9  wherein the sales gas product consists of essentially all propane and butanes present in the well fluid feed that for dewpoint specification requirements could not be separated into the sales gas product. 
     
     
         11 . The process of  claim 10  wherein the hydrocarbon portion of the sales oil product comprises essentially only pentanes and heavier components. 
     
     
         12 . The process of  claim 10  wherein the hydrocarbon portion of the sales oil product comprises almost all pentanes and heavier from the hydrocarbon well fluid feed. 
     
     
         13 . A separation unit process for a hydrocarbon fluid feed from a wellhead source comprising:
 (a) separating the fluid feed in a high pressure drum to form an HP gas and an HP liquid and separating the low pressure feed in a low pressure drum to form an LP gas and an LP liquid;   (b) combining the LP liquid and HP liquid and separating the combined stream in a stabilizer column to form stabilizer liquid bottoms, all or a portion of which forms an oil product; and   (c) compressing and cooling the LP gas and combining it with the HP gas, where a gas portion of the combined gas is separated in an LP column to form an LP column overhead gas, which is compressed and cooled, a portion of which is compressed and cooled to form a sales gas product.   
     
     
         14 . The process of  claim 13  wherein the sales gas product comprises 70 percent or more of the propane and butanes in the fluid feed. 
     
     
         15 . The process of  claim 14  wherein the sales gas product meets specifications for a transportation pipeline in which the sales gas product is transported from a wellhead area. 
     
     
         16 . The process of  claim 15  wherein the sales gas product consists of essentially all propane and butanes that for dewpoint specification requirements could not be separated into the sales gas product. 
     
     
         17 . The process of  claim 15  wherein the hydrocarbon portion of the condensate product comprises essentially only pentanes and heavier components. 
     
     
         18 . The process of  claim 15  wherein the hydrocarbon portion of the condensate product comprises essentially all pentanes and heavier from the fluid feed.