Hydrate formation for gas separation

Abstract

A gas separation or gas transportation process forms a gas hydrate from an aqueous feed and a gas feed having a hydrate P-T stability envelope. While in the presence of the aqueous feed, the gas feed is initially pressurized to an operating pressure and cooled to an operating temperature which are inside the hydrate P-T stability envelope to form a gas hydrate from at least a portion of the gas feed and at least a portion of the aqueous feed. The resulting gas hydrate is readily separable from any remaining gas and stable for transport.

I claim: 
     
         1 . A process for producing a gas hydrate comprising cooling a hydrocarbon gas and an initial water in liquid phase by contact with a cooler heat transfer surface to convert at least a portion of said hydrocarbon gas and at least a portion of said initial water to a solid gas hydrate. 
     
     
         2 . The process of  claim 1  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and a remaining portion of said initial water in liquid phase. 
     
     
         3 . The process of  claim 1  wherein said hydrocarbon gas and initial water are included within a fluid stream mixture contacting said cooler heat transfer surface. 
     
     
         4 . The process of  claim 3  wherein said fluid stream mixture further includes a hydrocarbon liquid. 
     
     
         5 . The process of  claim 4  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and said hydrocarbon liquid. 
     
     
         6 . The process of  claim 3  wherein said initial water is a limiting reactant, said process further comprising adding an additive water in liquid phase to said hydrocarbon gas and said initial water, thereby converting substantially all of said hydrocarbon gas to said solid gas hydrate. 
     
     
         7 . The process of  claim 3  further comprising adding an additive water in liquid phase to said fluid stream mixture before or while contacting said cooler heat transfer surface. 
     
     
         8 . The process of  claim 7  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and at least a portion of said additive water. 
     
     
         9 . The process of  claim 1  further comprising adding an additive water in liquid phase to said solid gas hydrate, thereby forming a gas hydrate slurry. 
     
     
         10 . A process for converting a fluid stream to a gas hydrate comprising:
 conveying a fluid stream past a cooler heat transfer surface while contacting said fluid stream with said cooler heat transfer surface, wherein said fluid stream comprises a hydrocarbon gas and an initial water in liquid phase;   cooling said fluid stream upon contact with said cooler heat transfer surface to a temperature below a gas hydrate formation temperature of said hydrocarbon gas; and   converting at least a portion of said hydrocarbon gas and at least a portion of said initial water to a solid gas hydrate.   
     
     
         11 . The process of  claim 10  wherein said cooler heat transfer surface is a first face on a first side of a wall, further wherein said wall has a second face on an opposite second side of said wall and said wall is enclosed within a vessel. 
     
     
         12 . The process of  claim 11  wherein said fluid stream is conveyed through said vessel while being conveyed past and contacting said first face of said wall and said at least a portion of said hydrocarbon gas and said at least a portion of said initial water are converted to said solid gas hydrate in said vessel on said first side of said wall. 
     
     
         13 . The process of  claim 11  wherein said vessel has a first end and a second end, further wherein said hydrocarbon gas and said initial water in liquid phase are fed to said vessel at or proximal to said first end of said vessel and said solid gas hydrate is withdrawn from said vessel at or proximal to said second end of said vessel. 
     
     
         14 . The process of  claim 12  wherein said vessel is substantially vertically oriented and said first end is a lower end of said vessel and said second end is an upper end of said vessel. 
     
     
         15 . The process of  claim 11  further comprising conveying a heat transfer medium through said vessel on said second side of said wall past said second face of said wall while contacting said second face, thereby cooling said first face of said wall. 
     
     
         16 . The process of  claim 15  wherein said wall maintains said heat transfer medium on said second side of said wall in fluid isolation from said fluid stream on said first side of said wall. 
     
     
         17 . The process of  claim 11  wherein said wall is a cylindrical wall of a tube extending through said vessel. 
     
     
         18 . The process of  claim 10  wherein said fluid stream comprises a hydrocarbon production stream and said hydrocarbon gas is natural gas. 
     
     
         19 . A process for producing a gas hydrate comprising fluidizing solid gas hydrate particles by co-currently conveying a hydrocarbon gas and an initial water in liquid phase through a vessel containing said solid gas hydrate particles thereby forming a fluidized bed including said solid gas hydrate particles, hydrocarbon gas and initial water in liquid phase, while converting at least a portion of said hydrocarbon gas and at least a portion of said initial water in said fluidized bed to additional solid gas hydrate particles. 
     
     
         20 . The process of  claim 19  further comprising cooling said fluidized bed to a temperature below a gas hydrate formation temperature of said hydrocarbon gas by conveying said fluidized bed past a cooler heat transfer surface and contacting said hydrocarbon gas and said initial water with said cooler heat transfer surface. 
     
     
         21 . The process of  claim 19  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and a remaining portion of said initial water. 
     
     
         22 . The process of  claim 19  wherein said fluidized bed further includes a hydrocarbon liquid. 
     
     
         23 . The process of  claim 22  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and said hydrocarbon liquid. 
     
     
         24 . The process of  claim 19  wherein said initial water is a limiting reactant, said process further comprising adding an additive water in liquid phase to said fluidized bed, thereby converting substantially all of said hydrocarbon gas to said solid gas hydrate. 
     
     
         25 . The process of  claim 24  further comprising forming a gas hydrate slurry comprising said solid gas hydrate and at least a portion of said additive water.