Compressing system, and gas compressing method

Abstract

A compressing system includes a compression section that compresses a target gas to an intermediate pressure, which is equal to or higher than a critical pressure and lower than a target pressure to generate an intermediate supercritical fluid, a cooling section that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid, and a pumping section that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure. At least one of the intermediate supercritical pressure liquid compressed in the pumping section, a low-temperature liquid generated by extracting the intermediate supercritical pressure liquid on the upstream side of the pumping section to reduce pressure to near the critical pressure, and an external cooling medium is used as a cooling medium in the cooling section.

1 - 6 . (canceled) 
     
     
         7 . A compressing system that compresses a target gas to a pressure that is equal to or higher than a target pressure higher than a critical pressure, the compressing system comprising:
 a compression section that compresses the target gas to an intermediate pressure, which is equal to or higher than the critical pressure and is lower than the target pressure to generate an intermediate supercritical fluid;   a cooling section that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid;   a pumping section that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure; and   a heating section that heats the intermediate supercritical pressure liquid compressed in the pumping section to near the critical temperature,   wherein the cooling section has a main cooling part that performs heat exchange with the heating section to cool the intermediate supercritical fluid.   
     
     
         8 . The compressing system according to  claim 7 , further comprising an extracting and decompression section that is provided between the cooling section and the pumping section to extract the intermediate supercritical pressure liquid to reduce pressure to near the critical pressure to generate a low-temperature liquid,
 wherein the main cooling part performs heat exchange with the low-temperature liquid generated in the extracting and decompression section to cool the intermediate supercritical fluid.   
     
     
         9 . A compressing system that compresses a target gas to a pressure that is equal to or higher than a target pressure higher than a critical pressure, the compressing system comprising:
 a compression section that compresses the target gas to an intermediate pressure, which is equal to or higher than the critical pressure and is lower than the target pressure to generate an intermediate supercritical fluid;   a cooling section that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid;   a pumping section that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure; and   an extracting and decompression section that is provided between the cooling section and the pumping section to extract the intermediate supercritical pressure liquid to reduce pressure to near the critical pressure to generate a low-temperature liquid,   wherein the cooling section has a main cooling part that performs heat exchange with the low-temperature liquid generated in the extracting and decompression section to cool the intermediate supercritical fluid.   
     
     
         10 . The compressing system according to  claim 8 ,
 wherein a gas or supercritical fluid, which is heated, evaporated, and generated when heat exchange with the low-temperature liquid generated in the extracting and decompression section is performed in the main cooling part, is returned to an equivalent pressure part in the compression section.   
     
     
         11 . The compressing system according to  claim 9 ,
 wherein a gas or supercritical fluid, which is heated, evaporated, and generated when heat exchange with the low-temperature liquid generated in the extracting and decompression section is performed in the main cooling part, is returned to an equivalent pressure part in the compression section.   
     
     
         12 . The compressing system according to  claim 7 ,
 wherein the cooling section has a pre-cooling part that performs heat exchange with an external cooling medium to cool the intermediate supercritical fluid to send the intermediate supercritical fluid to the main cooling part.   
     
     
         13 . The compressing system according to  claim 8 ,
 wherein the cooling section has a pre-cooling part that performs heat exchange with an external cooling medium to cool the intermediate supercritical fluid to send the intermediate supercritical fluid to the main cooling part.   
     
     
         14 . The compressing system according to  claim 9 ,
 wherein the cooling section has a pre-cooling part that performs heat exchange with an external cooling medium to cool the intermediate supercritical fluid to send the intermediate supercritical fluid to the main cooling part.   
     
     
         15 . The compressing system according to  claim 10 ,
 wherein the cooling section has a pre-cooling part that performs heat exchange with an external cooling medium to cool the intermediate supercritical fluid to send the intermediate supercritical fluid to the main cooling part.   
     
     
         16 . The compressing system according to  claim 11 ,
 wherein the cooling section has a pre-cooling part that performs heat exchange with an external cooling medium to cool the intermediate supercritical fluid to send the intermediate supercritical fluid to the main cooling part.   
     
     
         17 . A gas compressing method that compresses a target gas to a pressure that is equal to or higher than a target pressure higher than a critical pressure, the gas compressing method comprising:
 a compression step of compressing the target gas to an intermediate pressure, which is equal to or higher than the critical pressure and is lower than the target pressure to generate an intermediate supercritical fluid;   a cooling step of cooling the intermediate supercritical fluid generated in the compression step to near a critical temperature to generate an intermediate supercritical pressure liquid; and   a pumping step of compressing the intermediate supercritical pressure liquid generated in the cooling step to a pressure that is equal to or higher than the target pressure,   wherein the intermediate supercritical fluid is cooled in the cooling step, using at least one of the intermediate supercritical pressure liquid compressed in the pumping step, a low-temperature liquid generated by extracting the intermediate supercritical pressure liquid before the start of the pumping step and by reducing pressure to near the critical pressure, and an external cooling medium as a cooling medium.