Natural gas fractional distillation apparatus

Abstract

Disclosed is a natural gas fractional distillation apparatus. The natural gas fractional distillation apparatus according to one embodiment of the present invention comprises: a gas-liquid separator into which condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream; a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream; a first heat exchanger which condenses the first vapor stream separated in the gas separator; a first expander which expands the first vapor stream condensed in the first heat exchanger; a second expander which expands the second vapor stream separated in the gas separator; and a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream expanded in the first expander, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane. The first heat exchanger is capable of exchanging heat between the first vapor stream separated in the gas separator and the first vapor stream and the overhead vapor stream expanded in the first expander.

1 . A natural gas fractional distillation apparatus comprising:
 a gas-liquid separator into which a condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream;   a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream;   a first heat exchanger which condenses the first vapor stream separated in the gas separator;   a first expander which expands the first vapor stream condensed in the first heat exchanger;   a second expander which expands the second vapor separated in the gas separator; and   a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream expanded in the first expander, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane,   wherein the first heat exchanger exchanges heat among the first vapor stream separated in the gas separator, the first vapor stream expanded in the first expander, and the overhead vapor stream.   
     
     
         2 . A natural gas fractional distillation apparatus comprising:
 a gas-liquid separator into which a condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream;   a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream;   a first heat exchanger which condenses the first vapor stream separated in the gas separator;   a first expander which expands the first vapor stream condensed in the first heat exchanger;   a second expander which expands the second vapor separated in the gas separator; and   a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream expanded in the first expander, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane,   wherein the first heat exchanger exchanges heat among the first vapor stream separated in the gas separator, the second vapor stream expanded in the second expander, and the overhead vapor stream.   
     
     
         3 . The natural gas fractional distillation apparatus of  claim 1 , further comprising a second heat exchanger which discharges the condensed natural gas by exchanging heat between a natural gas and the overhead vapor stream that is discharged after heat exchange in the first heat exchanger. 
     
     
         4 . The natural gas fractional distillation apparatus of  claim 3 , further comprising a compressor which compresses the overhead vapor stream that is discharged after heat exchange in the second heat exchanger. 
     
     
         5 . A natural gas fractional distillation apparatus comprising:
 a gas-liquid separator into which a condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream;   a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream;   a first heat exchanger which condenses the first vapor stream separated in the gas separator;   a first expander which expands the first vapor stream condensed in the first heat exchanger;   a second expander which expands the second vapor separated in the gas separator;   a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream expanded in the first expander, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane; and   a second heat exchanger which discharges the condensed natural gas by exchanging heat among the overhead vapor stream that is discharged from the first heat exchanger after heat exchange with the first vapor stream in the first heat exchanger, the first vapor stream expanded in the first expander, and a natural gas.   
     
     
         6 . A natural gas fractional distillation apparatus comprising:
 a gas-liquid separator into which a condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream;   a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream;   a first heat exchanger which condenses the first vapor stream separated in the gas separator;   a first expander which expands the first vapor stream condensed in the first heat exchanger;   a second expander which expands the second vapor separated in the gas separator;   a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream expanded in the first expander, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane; and   a second heat exchanger which discharges the condensed natural gas by exchanging heat among the overhead vapor stream that is discharged from the first heat exchanger after heat exchange with the first vapor stream in the first heat exchanger, the second vapor stream expanded in the second expander, and a natural gas.   
     
     
         7 . The natural gas fractional distillation apparatus of  claim 5 , further comprising a compressor which compresses the overhead vapor stream that is discharged after heat exchange in the second heat exchanger. 
     
     
         8 . A natural gas fractional distillation apparatus comprising:
 a gas-liquid separator into which a condensed natural gas flows and which separates the condensed natural gas into a vapor stream and a liquid stream;   a gas separator which separates the vapor stream separated in the gas-liquid separator into a first vapor stream and a second vapor stream;   a first heat exchanger which condenses the first vapor stream separated in the gas separator;   a first expander which expands the first vapor stream condensed in the first heat exchanger;   a third heat exchanger which heats the first vapor stream expanded in the first expander;   a second expander which expands the second vapor separated in the gas separator; and   a distillation tower into which the liquid stream separated in the gas-liquid separator, the first vapor stream heated in the third heat exchanger, and the second vapor stream expanded in the second expander flow in order to be divided into an overhead vapor stream containing methane and a component-reinforced lower stream that is heavier than methane,   wherein the first heat exchanger exchanges heat between the first vapor stream separated in the gas separator and the overhead vapor stream, and   the third heat exchanger exchanges heat between the first vapor stream expanded in the first expander and the overhead vapor stream discharged from the first heat exchanger.   
     
     
         9 . The natural gas fractional distillation apparatus of  claim 8 , further comprising a second heat exchanger which discharges the condensed natural gas by exchanging heat between a natural gas and the overhead vapor stream that is discharged after heat exchange in the third heat exchanger. 
     
     
         10 . The natural gas fractional distillation apparatus of  claim 9 , further comprising a compressor which compresses the overhead vapor stream that is discharged after heat exchange in the second heat exchanger. 
     
     
         11 . The natural gas fractional distillation apparatus of  claim 1 , wherein the gas separator separates the vapor stream into the first vapor stream and the second vapor stream in a ratio of 2:8 to 1:9.