Thermally activated pressure booster for heat pumping and power generation

Abstract

Thermally activated systems and related processes for raising the pressure of a gaseous working fluid are described. The systems and processes can be used for both winter heating and summer cooling with increased efficiency. They can also be used for other applications in need of an efficient thermally driven compressor, such as a power generation process.

1 . A thermally activated system for increasing the pressure of a gaseous working fluid, comprising a working fluid having a bubble point of less than 20° C. when the working fluid is at 1 atm pressure, and a solvent comprising an organic oxygenate containing in its molecule at least one oxygen atom (O) and at least one atom selected from the group consisting of nitrogen (N), sulfur (S), phosphorus (P), fluorine (F), and a combination thereof, and the dew point of the solvent is greater than 130° C. when the solvent is at 1 atm. 
     
     
         2 . The thermally activated system of  claim 1 , comprising:
 an absorber, in which a lower pressure, substantially gaseous stream of the working fluid is absorbed into a lower pressure, liquid stream of an absorbent to form a liquid solution, wherein the absorbent comprises components of the working fluid and the solvent;   a cooler that removes heat from the absorber;   a pressure boosting device that increases the pressure of at least a portion of the liquid solution to obtain a higher pressure liquid solution; and   a generator that separates at least a portion of the higher pressure liquid solution into at least a higher pressure, substantially vaporized stream of the working fluid and a higher pressure, liquid stream of the absorbent.   
     
     
         3 . The thermally activated system of  claim 2 , further comprising:
 a condenser that substantially condenses at least a portion of the higher pressure, substantially vaporized stream of the working fluid to obtain a substantially condensed stream of the working fluid;   a pressure reducing device that reduces the pressure of at least a portion of the substantially condensed stream of the working fluid to obtain a lower pressure stream of the working fluid; and   an evaporator that at least partially vaporizes at least a portion of the lower pressure stream of the working fluid to obtain an at least partially vaporized stream of the working fluid, while removing heat from another heat source,   wherein the other heat source in the evaporator is heat from environment of an enclosed space or a process stream when the thermally activated system is used for heating the enclosed space or the process stream, or heat from an enclosed space or a process stream when the thermally activated system is used for cooling the enclosed space or the process stream.   
     
     
         4 . The thermally activated system of  claim 3 , further comprising a heat exchanger that cools at least a portion of the substantially condensed stream of the working fluid from the condenser to obtain a sub-cooled stream of the working fluid, while heating another stream, wherein at least a portion of the sub-cooled stream of the working fluid is subsequently fed to the pressure reducing device to obtain the lower pressure stream of the working fluid, and the other stream in the heat exchanger comprises at least a portion of the at least partially vaporized stream of the working fluid from the evaporator, heating of which results in the lower pressure, substantially gaseous stream of the working fluid, at least a portion of which is fed to the absorber. 
     
     
         5 . The thermally activated system of  claim 3 , wherein the working fluid is selected from the group consisting of R134a, dimethyl ether, R152a, CH 3 I (R13I1), propane, isopropane, propylene, isobutane, n-butane, HFO1234yf, and a combination thereof, and the solvent has a viscosity of less than 2.5 cP at 20° C. 
     
     
         6 . The thermally activated system of  claim 3 , wherein the solvent is selected from N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and a combination thereof. 
     
     
         7 . The thermally activated system of  claim 1 , comprising:
 an absorber, in which a lower pressure, substantially gaseous stream of a working fluid is absorbed into a lower pressure, liquid stream of an absorbent to form a liquid solution, wherein the working fluid is selected from the group consisting of R134a, dimethyl ether, R152a, CH 3 I (R13I1), propane, isopropane, propylene, isobutane, n-butane, HFO1234yf, and a combination thereof, and the absorbent comprises components of the working fluid and a solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and a combination thereof;   a cooler that removes heat from the absorber;   a pressure boosting device that increases the pressure of at least a portion of the liquid solution to obtain a higher pressure liquid solution;   a generator that separates the higher pressure liquid solution into at least a higher pressure, substantially vaporized stream of the working fluid and a higher pressure, liquid stream of the absorbent;   a condenser that substantially condenses at least a portion of the higher pressure, substantially vaporized stream of the working fluid to obtain a substantially condensed stream of the working fluid;   a heat exchanger that cools at least a portion of the substantially condensed stream of the working fluid to obtain a sub-cooled stream of the working fluid, while heating another stream,   a pressure reducing device that reduces the pressure of at least a portion of the sub-cooled stream of the working fluid to obtain a lower pressure stream of the working fluid;   an evaporator that at least partially vaporizes at least a portion of the lower pressure stream of the working fluid to obtain an at least partially vaporized stream of the working fluid, while removing heat from another heat source, wherein   the other heat source is heat from environment of an enclosed space or a process stream when the thermally activated system is used for heating the enclosed space or the process stream, or heat from an enclosed space or a process stream when the thermally activated system is used for cooling the enclosed space or the process stream, and   the other stream in the heat exchanger comprises at least a portion of the at least partially vaporized stream of the working fluid, heating of which results in the lower pressure, substantially gaseous stream of the working fluid, at least a portion of which is fed to the absorber;   a second heat exchanger that cools at least a portion of the higher pressure, liquid stream of the absorbent to obtain a sub-cooled, liquid stream of the absorbent; and   a second pressure reducing device that reduces the pressure of at least a portion the sub-cooled, liquid stream of the absorbent to obtain the lower pressure, liquid stream of the absorbent, at least a portion of which is fed to the absorber.   
     
     
         8 . The thermally activated system of  claim 7 , wherein the second heat exchanger cools at least a portion of the higher pressure, liquid stream of the absorbent from the bottom section of the generator to obtain the sub-cooled liquid stream of the absorbent, while heating and partially vaporizing at least a portion of the higher pressure, liquid solution from the pressure boosting device to obtain a higher pressure, two-phase stream, which is subsequently fed to an intermediate location of the generator. 
     
     
         9 . The thermally activated system of  claim 1 , comprising more than one generators. 
     
     
         10 . A power generation system, comprising the thermally activated system of  claim 2  and an expander, wherein at least a portion of the higher pressure, substantially vaporized stream of the working fluid from the generator is expanded in the expander to generate mechanical energy, and at least a portion of the exhaust stream of the working fluid from the expander is absorbed into the lower pressure, liquid stream of the absorbent in the absorber. 
     
     
         11 . A thermally activated process for increasing the pressure of a gaseous working fluid, comprising using a working fluid having a bubble point of less than 20° C. when the working fluid is at 1 atm pressure, and a solvent comprising an organic oxygenate containing in its molecule at least one oxygen atom (O) and at least one atom selected from the group consisting of nitrogen (N), sulfur (S), phosphorus (P), fluorine (F), and a combination thereof, and the dew point of the solvent is greater than 130° C. when the solvent is at 1 atm. 
     
     
         12 . The thermally activated process of  claim 11 , comprising:
 absorbing a lower pressure, substantially gaseous stream of the working fluid into a lower pressure, liquid stream of an absorbent in an absorber to obtain a liquid solution, wherein the absorbent comprises components of the working fluid and the solvent;   removing heat from the absorber;   increasing the pressure of at least a portion of the liquid solution to obtain a higher pressure liquid solution; and   separating at least a portion of the higher pressure liquid solution in a generator to obtain at least a higher pressure, substantially vaporized stream of the working fluid and a higher pressure, liquid stream of the absorbent.   
     
     
         13 . The thermally activated process of  claim 12 , further comprising:
 substantially condensing at least a portion of the higher pressure, substantially vaporized stream of the working fluid in a condenser to obtain a substantially condensed stream of the working fluid;   reducing the pressure of at least a portion of the substantially condensed stream of the working fluid to obtain a lower pressure stream of the working fluid; and   vaporizing at least a portion of the lower pressure stream of the working fluid in an evaporator to obtain an at least partially vaporized stream of the working fluid, while removing heat from another heat source,   wherein the other heat source in the vaporizing step is heat from environment of an enclosed space or a process stream when the thermally activated process is used for heating the enclosed space or the process stream, or heat from the an enclosed space or a process stream when the thermally activated process is used for cooling the enclosed space or the process stream.   
     
     
         14 . The thermally activated process of  claim 13 , further comprising:
 cooling at least a portion of the substantially condensed stream of the working fluid in a heat exchanger to obtain a sub-cooled stream of the working fluid, while heating another stream, wherein the other stream in the heat exchanger comprises at least a portion of the at least partially vaporized stream of the working fluid from the evaporator, and heating of which results in the lower pressure, substantially gaseous stream of the working fluid;   feeding at least a portion of the lower pressure, substantially gaseous stream of the working fluid to the absorber; and   reducing the pressure of at least a portion of the sub-cooled stream of the working fluid to obtain the lower pressure stream of the working fluid.   
     
     
         15 . A thermally activated process for increasing the pressure of a gaseous working fluid, comprising:
 absorbing a lower pressure, substantially gaseous stream of a working fluid into a lower pressure, liquid stream of an absorbent in an absorber to obtain a liquid solution, wherein the working fluid is selected from the group consisting of R134a, dimethyl ether, R152a, CH 3 I (R13I1), propane, isopropane, propylene, isobutane, n-butane, HFO1234yf, and a combination thereof, and the absorbent comprises components of the working fluid and a solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and a combination thereof;   removing heat from the absorber;   increasing the pressure of at least a portion of the liquid solution by a pressure boosting device to obtain a higher pressure liquid solution;   separating at least a portion of the higher pressure liquid solution in a generator to obtain at least a higher pressure, substantially vaporized stream of the working fluid and a higher pressure, liquid stream of the absorbent;   substantially condensing at least a portion of the higher pressure, substantially vaporized stream of the working fluid in a condenser to obtain a substantially condensed stream of the working fluid;   cooling at least a portion of the substantially condensed stream of the working fluid in a heat exchanger to obtain a sub-cooled stream of the working fluid, while heating another stream;   reducing the pressure of at least a portion of the sub-cooled stream of the working fluid to obtain a lower pressure stream of the working fluid;   vaporizing at least a portion of the lower pressure stream of the working fluid in an evaporator to obtain an at least partially vaporized stream of the working fluid, while removing heat from another heat source, wherein
 the other heat source in the vaporizing step is heat from environment of an enclosed space or a process stream when the thermally activated process is used for heating the enclosed space or the process stream, or heat from an enclosed space or a process stream when the thermally activated process is used for cooling the enclosed space or the process stream, and 
 the other stream in the heat exchanger comprises the at least partially vaporized stream of the working fluid from the evaporator, heating of which results in the lower pressure, substantially gaseous stream of the working fluid; 
   feeding at least a portion of the lower pressure, substantially gaseous stream of the working fluid to the absorber;   cooling at least a portion of the higher pressure, liquid stream of the absorbent in a second heat exchanger to obtain a sub-cooled, liquid stream of the absorbent;   reducing the pressure of at least a portion of the sub-cooled, liquid stream of the absorbent to obtain the lower pressure, liquid stream of the absorbent; and   feeding at least a portion of the lower pressure, liquid stream of the absorbent to the absorber.   
     
     
         16 . The thermally activated process of  claim 15 , wherein the second heat exchanger cools at least a portion of the higher pressure, liquid stream of the absorbent from the bottom section of the generator to obtain the sub-cooled, liquid stream of the absorbent, while heating and partially vaporizing at least a portion of the higher pressure, liquid solution from the pressure boosting device to obtain a higher pressure, two-phase stream, at least a portion of which is subsequently fed to an intermediate location of the generator. 
     
     
         17 . The thermally activated process of  claim 16 , wherein the portion of the higher pressure, liquid solution being heated and partially vaporized constitutes 80-99% (mol) of the higher pressure, liquid solution, and 1-20% (mol) of the higher pressure, liquid solution is sent to the top of the generator without being heated and partially vaporized. 
     
     
         18 . The process of  claim 17 , wherein the higher pressure, substantially vaporized stream of the working fluid obtained from the generator contains up to 5% (mol) of the solvent, and the at least partially vaporized stream of the working fluid obtained from the evaporator contains 0.1-5% (mol) liquid. 
     
     
         19 . The thermally activated process of  claim 11 , wherein the separating step utilizes more than one generators. 
     
     
         20 . A power generation process, comprising
 a. the thermally activated process of  claim 12 ,   b. expanding at least a portion of the higher pressure, substantially vaporized stream of the working fluid in an expander to generate mechanical energy, and   c. absorbing at least a portion of the exhaust stream of the working fluid from the expander into the lower pressure, liquid stream of the absorbent in the absorber.