Methods and apparatuses for removing amines from extracted hydrocarbon streams

Abstract

Methods and apparatuses for processing hydrocarbons are provided. In one embodiment, a method for processing a hydrocarbon stream includes feeding a hydrocarbon stream including amine and mercaptan to an extraction zone. The method includes contacting the hydrocarbon stream with an alkaline stream in the extraction zone to convert the mercaptan to a mercaptide. Further, the method includes contacting the hydrocarbon stream with water in the extraction zone to remove the amine from the hydrocarbon stream.

What is claimed is: 
     
         1 . A method for processing a hydrocarbon stream, the method comprising:
 feeding a hydrocarbon stream including amine and mercaptan to an extraction zone;   contacting the hydrocarbon stream with an alkaline stream in the extraction zone to convert the mercaptan to a mercaptide; and   contacting the hydrocarbon stream with water in the extraction zone to remove the amine from the hydrocarbon stream.   
     
     
         2 . The method of  claim 1  further comprising
 removing an effluent from the extraction zone; 
 separating a recovered alkaline stream from the effluent; and 
 dehydrating the recovered alkaline stream to form the alkaline stream. 
 
     
     
         3 . The method of  claim 1  further comprising:
 withdrawing the hydrocarbon stream from the extraction zone; and 
 passing the hydrocarbon stream through a coalescer to remove alkaline components from the hydrocarbon stream before withdrawing the hydrocarbon stream from the extraction zone. 
 
     
     
         4 . The method of  claim 1  wherein the extraction zone includes an extraction section positioned below a wash section, wherein contacting the hydrocarbon stream with the alkaline stream comprises contacting the hydrocarbon stream with the alkaline stream in the extraction section, and wherein contacting the hydrocarbon stream with water comprises contacting the hydrocarbon stream with water in the wash section. 
     
     
         5 . The method of  claim 4  wherein the hydrocarbon stream flows upward through the extraction section and through the wash section, and wherein the method further comprises:
 feeding the water to the wash section, wherein the water flows downward through the wash section and through the extraction section; and 
 feeding the alkaline stream to the extraction section, wherein the alkaline stream flows downward through the extraction section. 
 
     
     
         6 . The method of  claim 1  further comprising removing an effluent including the alkaline stream, the mercaptide, the water, and the amine from the extraction zone. 
     
     
         7 . The method of  claim 6  further comprising:
 oxidizing the effluent and converting the mercaptide to disulfide; and 
 separating the effluent to remove the disulfide from a recovered alkaline stream. 
 
     
     
         8 . The method of  claim 7  further comprising:
 dehydrating the recovered alkaline stream to form the alkaline stream; and 
 feeding the alkaline stream to the extraction zone to contact the hydrocarbon stream therein. 
 
     
     
         9 . The method of  claim 1  wherein:
 feeding the hydrocarbon stream including amine and mercaptan to the extraction zone comprises feeding the hydrocarbon stream to the extraction zone in an extraction vessel; 
 contacting the hydrocarbon stream with the alkaline stream in the extraction zone comprises contacting the hydrocarbon stream with the alkaline stream in the extraction vessel; and 
 contacting the hydrocarbon stream with water in the extraction zone comprises contacting the hydrocarbon stream with water in the extraction vessel. 
 
     
     
         10 . The method of  claim 1  wherein feeding a hydrocarbon stream including amine and mercaptan to the extraction zone comprises feeding a stream of liquefied petroleum gas to the extraction zone. 
     
     
         11 . A method for processing a hydrocarbon stream, the method comprising:
 feeding a hydrocarbon stream containing sulfur compounds and acid gases to a prewash zone containing amine to remove the acid gases;   withdrawing a prewashed hydrocarbon stream from the prewash zone;   feeding the prewashed hydrocarbon stream to an extraction zone;   contacting the prewashed hydrocarbon stream with an alkaline stream in the extraction zone to convert mercaptans to mercaptides;   contacting the hydrocarbon stream with water in the extraction zone, wherein the water removes amine entrained in the hydrocarbon stream; and   withdrawing an extracted hydrocarbon stream from the extraction zone.   
     
     
         12 . The method of  claim 11  further comprising:
 removing an effluent from the lower section of the extraction zone; 
 separating the effluent to form a recovered alkaline stream; 
 dehydrating the recovered alkaline stream to form the alkaline stream; and 
 feeding the alkaline stream to the lower section of the extraction zone to contact the prewashed hydrocarbon stream therein. 
 
     
     
         13 . The method of  claim 11  wherein the prewashed hydrocarbon stream flows upward through the extraction zone, wherein contacting the prewashed hydrocarbon stream with the alkaline stream comprises contacting the prewashed hydrocarbon stream with the alkaline stream in a lower section of the extraction zone, and wherein contacting the prewashed hydrocarbon stream with water comprises contacting the hydrocarbon stream with water in an upper section of the extraction zone. 
     
     
         14 . The method of  claim 13  further comprising:
 feeding water to the upper section of the extraction zone, wherein the water flows downward through the extraction zone; 
 feeding the alkaline stream to the lower section of the extraction zone, wherein the alkaline stream flows downward through the extraction zone; and 
 removing an effluent comprising the water, the alkaline stream, the mercaptides, and the amine from an outlet adjacent the lower section of the extraction zone. 
 
     
     
         15 . The method of  claim 14  further comprising passing the extracted hydrocarbon stream through a coalescer above the upper section of the extraction zone to remove alkaline components from the extracted hydrocarbon stream before withdrawing the extracted hydrocarbon stream from the extraction zone. 
     
     
         16 . The method of  claim 14  further comprising:
 adding air to the effluent; 
 oxidizing the effluent and converting the mercaptides to disulfides; and 
 separating the effluent to form a stream of air, a stream of disulfides and a recovered alkaline stream. 
 
     
     
         17 . The method of  claim 16  further comprising:
 dehydrating the recovered alkaline stream to form the alkaline stream with a higher alkali concentration than the prewash zone; and 
 feeding the alkaline stream to the lower section of the extraction zone to contact the prewashed hydrocarbon stream therein. 
 
     
     
         18 . The method  claim 11  wherein the extraction zone is directly above the prewash zone and wherein withdrawing the prewashed hydrocarbon stream from the prewash zone and feeding the prewashed hydrocarbon stream to the extraction zone comprises passing the prewashed hydrocarbon stream from the prewash zone to extraction zone via a conduit. 
     
     
         19 . The method of  claim 11  wherein:
 feeding the hydrocarbon stream comprises feeding the hydrocarbon stream at a location proximate a bottom of the prewash zone; 
 withdrawing the prewashed hydrocarbon stream from the prewash zone comprises withdrawing the prewashed hydrocarbon stream at a location proximate a top of the prewash zone; 
 feeding the prewashed hydrocarbon stream to the extraction zone comprises feeding the prewashed hydrocarbon stream to a lower section of the extraction zone; and 
 the method further comprises feeding the water to an upper section of the extraction zone. 
 
     
     
         20 . An apparatus for processing a hydrocarbon stream, the apparatus comprising:
 an extraction vessel including an extraction section positioned below a wash section;   a hydrocarbon conduit connected to the extraction vessel for delivering a hydrocarbon stream including a mercaptan and an amine for upward flow through the extraction section and through the wash section;   an alkaline conduit connected to the extraction vessel for delivering an alkaline stream for downward flow through the extraction section;   a water conduit connected to the extraction vessel for delivering water for downward flow through the wash section and through the extraction section; and   an effluent outlet for removing the alkaline stream and the water from the extraction vessel.