Removing chlathrate inhibitors from contaminated petroleum streams

Abstract

A process is presented for treating crude oil that contains a clathrate hydrate inhibitor. In the process, a crude oil contaminated with the inhibitor is maintained in a vessel at inhibitor removal conditions to produce a treated crude oil having a reduced methanol concentration.

1 . A process for removing methanol from crude oil, comprising maintaining a contaminated crude oil at methanol removal conditions in a vessel having a liquid volume and a vapor volume, wherein the contaminated crude oil contains in the range of from greater than 50 ppm methanol to less than 5000 ppm methanol, to produce a treated crude oil having a reduced methanol concentration. 
     
     
         2 . The process of  claim 1 , comprising producing the treated crude oil which contains less than 50 ppm methanol. 
     
     
         3 . The process of  claim 1 , comprising maintaining the contaminated crude oil at methanol removal conditions, including a temperature in the range of 10° C. to 150° C. and a pressure in the range of 5 kPa to 450 kPa. 
     
     
         4 . The process of  claim 1 , comprising maintaining the contaminated crude oil in the vessel for at least 8 hours. 
     
     
         5 . The process of  claim 1 , comprising maintaining the contaminated crude oil in the vessel having the vapor volume which contains a vapor phase blanketing material. 
     
     
         6 . The process of  claim 5 , comprising maintaining the contaminated crude oil in the vessel having the vapor volume which contains the vapor phase blanketing material comprising at least one of nitrogen, carbon dioxide, synthesis gas, air or gaseous hydrocarbons. 
     
     
         7 . The process of  claim 1 , further comprising passing a sweep gas through the vapor volume of the vessel. 
     
     
         8 . The process of  claim 7 , comprising passing the sweep gas which contains at least one of nitrogen, carbon dioxide, synthesis gas, air, and gaseous hydrocarbons. 
     
     
         9 . The process of  claim 7 , wherein the sweep gas passes through the vapor volume of the vessel at a superficial velocity of from 0.2 meters/second to 5 meters/second. 
     
     
         10 . The process of  claim 7 , further comprising recovering a contaminated sweep gas enriched in methanol from the vapor volume. 
     
     
         11 . The process of  claim 10 , further comprising combusting at least a portion of the contaminated sweep gas. 
     
     
         12 . The process of  claim 11 , further comprising recovering energy in the form of thermal energy, electrical energy or mechanical energy from the step of combusting. 
     
     
         13 . The process of  claim 10 , further comprising recovering at least a portion of the methanol from the contaminated sweep gas. 
     
     
         14 . The process of  claim 1 , further comprising contacting the treated crude oil with a liquid wash material and recovering a contaminated wash material and a washed crude oil. 
     
     
         15 . The process of  claim 14 , comprising contacting the treated crude oil with the liquid wash material, which is an aqueous liquid. 
     
     
         16 . The process of  claim 14 , wherein the liquid wash material and the treated crude oil are in a ratio of between 10:1 and 1:10. 
     
     
         17 . The process of  claim 14 , further comprising treating the contaminated wash material and recovering at least a portion of the methanol contained therein. 
     
     
         18 . The process of  claim 14 , comprising treating the contaminated wash material, wherein the liquid wash material comprises fresh water, seawater, brine or a combination thereof. 
     
     
         19 . The process of  claim 1 , further comprising passing a stripping gas through the contaminated crude oil in the vessel. 
     
     
         20 . The process of  claim 19 , comprising passing the stripping gas through the contaminated crude oil, wherein the stripping gas comprises at least one of nitrogen, carbon dioxide, synthesis gas, air, and gaseous hydrocarbons . 
     
     
         21 . A process for inhibiting methane hydrate formation in crude oil, comprising
 a) mixing a methanol-rich stream with crude oil in a crude oil production process to form contaminated crude oil; and   b) passing the contaminated crude oil at methanol removal conditions to a vessel having a liquid volume and a vapor volume, wherein the contaminated crude oil contains in the range of from greater than 50 ppm methanol to less than 5000 ppm methanol, to produce a treated crude oil having a methanol concentration of less than 50 ppm.