System for recovering natural gas liquid from low pressure source

Abstract

A system (102; 302) for recovering natural gas liquid from a low pressure gas source (110; 310), comprising a gas/gas heat exchanger (104; 304), fluid from the gas source flowing therethrough; at least one separator (108; 308) for receiving the fluid from the gas/gas heat exchanger (104; 304) and separating liquid from the gas, the gas being directed via a connecting pipe (116; 316) to the gas/gas heat exchanger (104; 304) where it cools the fluid from the gas source; characterised in that the connecting pipe (116; 316) includes expansion means (106; 322) for cooling the gas therein and liquid injection means (120; 320) for saturating the gas with liquid.

In the claims: 
     
         1 . A system ( 102 ;  302 ) for recovering natural gas liquid from a gas source ( 110 ;  310 ), comprising:
 a gas/gas heat exchanger ( 104 ;  304 ) including a first inlet and first outlet, fluid from the gas source flowing from the first inlet to the first outlet;   at least one separator ( 108 ;  308 ) for receiving the fluid from the first outlet of the gas/gas heat exchanger ( 104 ;  304 ) and separating liquid from the gas, the gas being directed via a connecting pipe ( 116 ;  316 ) to the gas/gas heat exchanger ( 104 ;  304 ) where it flows therethrough from a second inlet to a second outlet for cooling the fluid flowing between the first inlet and first outlet;   characterised in that the connecting pipe ( 116 ;  316 ) includes expansion means ( 106 ;  322 ) for cooling the gas therein and liquid injection means ( 120 ;  320 ) for saturating the gas with liquid.   
     
     
         2 . The system according to  claim 1  wherein the expansion means is a Joule-Thomson valve ( 106 ). 
     
     
         3 . The system according to  claim 1  wherein the expansion means is a Vortex-Tube Device or Supersonic Tube technology. 
     
     
         4 . The system according to  claim 1  wherein the expansion means is a turbo expander ( 322 ). 
     
     
         5 . The system according to  claim 1  wherein the liquid injection means is downstream of the expansion means. 
     
     
         6 . The system according to  claim 1  wherein liquid is injected downstream of the expansion means at a rate to enable the gas at the second outlet to be saturated. 
     
     
         7 . The system according to  claim 1  wherein liquid is injected in excess of the saturation amount to avoid solid deposition at the gas/gas heat exchanger. 
     
     
         8 . The system according to  claim 1  wherein the liquid used to saturate the gas is derived from the separator and/or other downstream sources. 
     
     
         9 . The system according to  claim 1  wherein the liquid injection means is a sprayer for spraying the liquid into the gas as a mist. 
     
     
         10 . The system according to  claim 1  wherein the liquid used to saturate the gas is water. 
     
     
         11 . The system according to  claim 1  wherein the liquid used to saturate the gas is mixed with a hydrate or ice inhibitor. 
     
     
         12 . The system according to  claim 11  wherein the hydrate or ice inhibitor is methanol or Mono Ethylene Glycol. 
     
     
         13 . The system according to  claim 1  wherein the gas source pressure of less than 2.1 MPa.