Method and system for condensing a gas

Abstract

The invention relates to a method for condensing a gas, wherein the gas is subjected to cooling in indirect heat exchange with a refrigerant and at least part of the refrigerant is subjected, after the heat exchange with the gas, to compression by means of a drive (GT1) that produces waste heat and to a partial or complete condensing process. After the partial or complete condensing process, a first portion of the refrigerant is subjected to the heat exchange with the gas and a second portion of the refrigerant is subjected, in succession, to pressurization, heating by means of the waste heat of the drive (GT1) and work-performing expansion and thereafter is fed back to the partial or complete condensing process. The invention further relates to a corresponding system.

1 . A method for condensing a gas, wherein the gas is subjected to cooling in indirect heat exchange with a refrigerant, and at least a part of the refrigerant is subjected, after the heat exchange with the gas, to compression using a drive that produces waste heat and to a partial or complete condensing process, wherein, after the partial or complete condensing process, a first portion of the refrigerant is subjected to the heat exchange with the gas, and that a second portion of the refrigerant is subjected, in succession, to pressurization, heating using the waste heat of the drive and to work-performing expansion, and thereafter is fed back to the partial or complete condensing process. 
     
     
         2 . The method according to  claim 1 , with which a mixed refrigerant is used as the refrigerant in one or more mixed refrigerant circuits and/or with which natural gas or a gas mixture formed using natural gas is used as the gas and/or with which a gas turbine is used as the drive that produces waste heat. 
     
     
         3 . The method according to  claim 1 , with which work performed during the work-performing expansion is used in addition to the drive in the compression of the same refrigerant. 
     
     
         4 . The method according to  claim 3 , with which the compression of the refrigerant comprises a first compression step to a first pressure level and a second compression step to a second pressure level above the first pressure level, wherein the drive is used in the first compression step and the work performed during the work-performing expansion is used in the second compression step. 
     
     
         5 . The method according to  claim 1 , with which the first and second portions are in each case portions of a first refrigerant, and with which work performed during the work-performing expansion is used in the compression of a second refrigerant, wherein the first refrigerant is a pure refrigerant and the second refrigerant is a mixed refrigerant, or wherein the first refrigerant is a mixed refrigerant and the second refrigerant is nitrogen. 
     
     
         6 . The method according to  claim 4 , with which the refrigerant is at least partially subjected to the first compression step and subsequently at least partially subjected to a first partial condensing process to obtain a first liquid fraction and a first gas fraction, wherein the first gas fraction is at least partially subjected to the second compression step and subsequently at least partially subjected to a second partial condensing process to obtain a second liquid fraction and a second gas fraction. 
     
     
         7 . The method according to  claim 6 , with which after its work-performing expansion, the second portion of the refrigerant is at least partially combined with the refrigerant or a part thereof before the latter is subjected to cooling for the first partial condensing process. 
     
     
         8 . The method according to  claim 6 , with which before its work-performing expansion, the second portion of the refrigerant is at least partially subjected to indirect heat exchange with the second portion of the refrigerant or a part thereof, after the latter was subjected to the work-performing expansion and before the latter is combined with the first gas fraction. 
     
     
         9 . The method according to  claim 6 , with which the second liquid fraction is at least partially expanded and combined with the refrigerant compressed in the first compression step. 
     
     
         10 . The method according to  claim 6 , with which a heat exchanger having a plurality of sections or a plurality of heat exchangers is used for cooling the gas in indirect heat exchange with the refrigerant, wherein the first portion of the refrigerant and the second gas fraction or parts thereof are further cooled to different temperature levels and reheated after expansion. 
     
     
         11 . The method according to  claim 1 , with which the work performed during the work-performing expansion is used in addition to the drive in the compression of a further refrigerant, with which the gas is subjected to cooling in indirect heat exchange. 
     
     
         12 . A system for condensing a gas, wherein the system has means configured to subject the gas to cooling in indirect heat exchange with a refrigerant, and at least a part of the refrigerant is subjected, after the heat exchange with the gas, to compression using a drive that produces waste heat and to a partial or complete condensing process, wherein means configured to subject, after the partial or complete condensing process, a first portion of the refrigerant to the heat exchange with the gas, and a second portion of the refrigerant, in succession, to pressurization, heating using the waste heat of the drive and to work-performing expansion, and thereafter to feed it back to the partial or complete condensing process. 
     
     
         13 . A system for condensing a gas, wherein the system has means configured to subject the gas to cooling in indirect heat exchange with a refrigerant, and at least a part of the refrigerant is subjected, after the heat exchange with the gas, to compression using a drive that produces waste heat and to a partial or complete condensing process, wherein means configured to subject, after the partial or complete condensing process, a first portion of the refrigerant to the heat exchange with the gas, and a second portion of the refrigerant, in succession, to pressurization, heating using the waste heat of the drive and to work-performing expansion, and thereafter to feed it back to the partial or complete condensing process, wherein the system is configured to carry out a method according to  claim 1 .