LPG Fractionation Recovery System

Abstract

A system for recovering an LPG fraction according to the present invention includes: a compressor increasing the pressure of excess gas such as associated gas; a deethanizer column dissolving, in a sponge oil, propane and butane contained in the excess gas and separating a gas having a carbon number of two or less from the excess gas; a sponge oil transfer pipe discharging the sponge oil from the deethanizer column; a debutanizer column separating propane and butane from the sponge oil; an LPG fraction discharge pipe discharging the fraction containing propane and butane from the debutanizer column; and a sponge oil return pipe returning the sponge oil from the debutanizer column to the deethanizer column.

1 . A system for recovering an LPG fraction comprising: a compressor increasing the pressure of all or a part of excess gas generated during the production of crude oil, the excess gas containing propane and butane;
 a deethanizer column bringing the pressurized excess gas into gas-liquid contact with a sponge oil so that propane and butane contained in the excess gas can be dissolved in the sponge oil, and a gas having a carbon number of two or less can be separated from the excess gas;   a sponge oil transfer pipe discharging from the deethanizer column, the sponge oil with propane and butane dissolved therein;   a debutanizer column connected to the deethanizer column via the sponge oil transfer pipe, and separating propane and butane from the sponge oil;   an LPG fraction discharge pipe discharging the fraction containing propane and butane from the debutanizer column; and   a sponge oil return pipe discharging the sponge oil from the debutanizer column and returning the sponge oil to the deethanizer column.   
     
     
         2 . The system for recovering the LPG fraction according to  claim 1 , wherein the compressor is driven by a motor or a gas engine using the excess gas as fuel. 
     
     
         3 . The system for recovering the LPG fraction according to  claim 1 , further comprising:
 a first circulation pipe branched from the sponge oil transfer pipe and returning a part of the sponge oil from the deethanizer column to the deethanizer column; and   a first reboiler arranged in the middle of the first circulation pipe,   wherein the first reboiler has a first main body section receiving the sponge oil; and a first heating pipe provided so as to pass through the inside of the first main body section and allowing a fluid heated by combustion of the excess gas to flow through the first heating pipe.   
     
     
         4 . The system for recovering the LPG fraction according to  claim 1 , further comprising:
 a second circulation pipe branched from the sponge oil return pipe and returning a part of the sponge oil from the debutanizer column to the debutanizer column; and   a second reboiler arranged m the middle of the second circulation pipe,   wherein the second reboiler has a second main body section receiving the sponge oil, and a second heating pipe provided so as to pass through the inside of the second main body section and allowing a fluid heated by combustion of the excess gas to flow through the second heating pipe.   
     
     
         5 . The system for recovering the LPG fraction according to  claim 1 , further comprising a depentanizer column supplied with a fraction having a carbon number of three or more from the debutanizer column through the LPG fraction discharge pipe, and separating a fraction having a carbon number of five or more from the supplied fraction. 
     
     
         6 . The system for recovering the LPG fraction according to  claim 1 , wherein the sponge oil is jet fuel or kerosene, or fraction corresponding to jet fuel or kerosene, or a mixture of hydrocarbons having a carbon number of 7 to 16, or normal paraffin or iso-paraffin having a carbon number of 10 to 14. 
     
     
         7 . The system for recovering the LPG fraction according to one  claim 1 , wherein the recovery rate of LPG fraction contained in the excess gas is 70 to 99%. 
     
     
         8 . The system for recovering the LPG fraction according to  claim 2 , further comprising:
 a first circulation pipe branched from the sponge oil transfer pipe and returning a part of the sponge oil from the deethanizer column to the deethanizer column; and   a first reboiler arranged in the middle of the first circulation pipe,   wherein the first reboiler has a first main body section receiving the sponge oil; and a first heating pipe provided so as to pass through the inside of the first main body section and allowing a fluid heated by combustion of the excess gas to flow through the first heating pipe.   
     
     
         9 . The system for recovering the LPG fraction according to  claim 2 , further comprising:
 a second circulation pipe branched from the sponge oil return pipe and returning a part of the sponge oil from the debutanizer column to the debutanizer column; and   a second reboiler arranged m the middle of the second circulation pipe,   wherein the second reboiler has a second main body section receiving the sponge oil, and a second heating pipe provided so as to pass through the inside of the second main body section and allowing a fluid heated by combustion of the excess gas to flow through the second heating pipe.   
     
     
         10 . The system for recovering the LPG fraction according to  claim 2 , further comprising a depentanizer column supplied with a fraction having a carbon number of three or more from the debutanizer column through the LPG fraction discharge pipe, and separating a fraction having a carbon number of five or more from the supplied fraction. 
     
     
         11 . The system for recovering the LPG fraction according to  claim 2 , wherein the sponge oil is jet fuel or kerosene, or fraction corresponding to jet fuel or kerosene, or a mixture of hydrocarbons having a carbon number of 7 to 16, or normal paraffin or iso-paraffin having a carbon number of 10 to 14. 
     
     
         12 . The system for recovering the LPG fraction according to  claim 2 , wherein the recovery rate of LPG fraction contained in the excess gas is 70 to 99%. 
     
     
         13 . The system for recovering the LPG fraction according to  claim 3 , further comprising:
 a second circulation pipe branched from the sponge oil return pipe and returning a part of the sponge oil from the debutanizer column to the debutanizer column; and   a second reboiler arranged m the middle of the second circulation pipe,   wherein the second reboiler has a second main body section receiving the sponge oil, and a second heating pipe provided so as to pass through the inside of the second main body section and allowing a fluid heated by combustion of the excess gas to flow through the second heating pipe.   
     
     
         14 . The system for recovering the LPG fraction according to  claim 3 , further comprising a depentanizer column supplied with a fraction having a carbon number of three or more from the debutanizer column through the LPG fraction discharge pipe, and separating a fraction having a carbon number of five or more from the supplied fraction. 
     
     
         15 . The system for recovering the LPG fraction according to  claim 3 , wherein the sponge oil is jet fuel or kerosene, or fraction corresponding to jet fuel or kerosene, or a mixture of hydrocarbons having a carbon number of 7 to 16, or normal paraffin or iso-paraffin having a carbon number of 10 to 14. 
     
     
         16 . The system for recovering the LPG fraction according to  claim 3 , wherein the recovery rate of LPG fraction contained in the excess gas is 70 to 99%. 
     
     
         17 . The system for recovering the LPG fraction according to  claim 4 , further comprising a depentanizer column supplied with a fraction having a carbon number of three or more from the debutanizer column through the LPG fraction discharge pipe, and separating a fraction having a carbon number of five or more from the supplied fraction. 
     
     
         18 . The system for recovering the LPG fraction according to  claim 4 , wherein the sponge oil is jet fuel or kerosene, or fraction corresponding to jet fuel or kerosene, or a mixture of hydrocarbons having a carbon number of 7 to 16, or normal paraffin or iso-paraffin having a carbon number of 10 to 14. 
     
     
         19 . The system for recovering the LPG fraction according to  claim 4 , wherein the recovery rate of LPG fraction contained in the excess gas is 70 to 99%. 
     
     
         20 . The system for recovering the LPG fraction according to  claim 5 , wherein the sponge oil is jet fuel or kerosene, or fraction corresponding to jet fuel or kerosene, or a mixture of hydrocarbons having a carbon number of 7 to 16, or normal paraffin or iso-paraffin having a carbon number of 10 to 14.