초록 ▼

A method for producing electrical energy is disclosed which uses a heat source, such as solar heat, geothermal heat, industrial waste heat or heat from power production processes, providing heat of 150° C. or below, further comprising an absorber system in which a working gas, primarily carbon dioxi

A method for producing electrical energy is disclosed which uses a heat source, such as solar heat, geothermal heat, industrial waste heat or heat from power production processes, providing heat of 150° C. or below, further comprising an absorber system in which a working gas, primarily carbon dioxide CO2, is absorbed into an absorbent, typically an amine, further comprising a reactor which receives heat from said heat source and in which the absorbent-CO2 mixture is split into CO2 and absorbent, further comprising an expansion machine, an electricity generator and auxiliary equipment such as pumps, pipes and heat exchangers. The system according to the method allows the cost-efficient production of electrical energy and cooling using low value heat source.

대표청구항 ▼

1. A method for producing electrical energy using an essentially closed loop system comprising the steps of: providing a reactor (7);accessing at least one external heat source (1) for providing thermal energy to the essentially closed loop system, the at least one external heat source being a low t

1. A method for producing electrical energy using an essentially closed loop system comprising the steps of: providing a reactor (7);accessing at least one external heat source (1) for providing thermal energy to the essentially closed loop system, the at least one external heat source being a low temperature heat source providing thermal energy at up to 150° C.;transferring thermal energy from the at least one external heat source to the reactor (7);providing an absorber system (3) for chemically absorbing carbon dioxide (CO2) into an absorbent liquid to provide a mix of CO2 gas and liquid absorbent (gas-absorbent mix) and to generate a low pressure;providing at least one pump device (6) for increasing the pressure of said gas-absorbent mix and allowing transfer of pressurized gas-absorbent mix to the reactor (7);provding a separator downstream of the pump device for separating said gas-absorbent mix and recycling part of said gas-absorbent mix to said absorber system;using thermal energy from the said heat source (1) to heat the pressurized gas-absorbent mix at the reactor, thereby splitting the pressurized gas-absorbent mix into a heated and pressurized CO2 gas and a heated absorbent liquid as output of the reactor;providing an expansion machine (15) with a generator (23) for producing electricity by expanding the heated and pressurized CO2 gas from the said reactor (7) into a low temperature CO2 gas by using the low pressure generated in the said absorber system (3);providing a pipe system that leads the said heated absorbent liquid exiting the reactor (7) and the low temperature CO2 gas exiting the expansion machine (15) to the said absorber system (3) so the CO2 gas is chemically re-absorbed into the heated absorbent liquid for the process to start over in a reversible reaction with the CO2 gas absorbed into the heated absorbent liquid in said absorber system (3);using said heated and pressurized CO2 gas to operate said expansion machine within a temperature interval between −78° C. and plus 150° C.;using in the absorber system a material capable of binding CO2;obtaining a CO2 pressure in said reactor of between 20 bar and 0.5 bar;obtaining a CO2 pressure in said absorber system of between 0.5 bar and 0.001 bar;the closed loop system continuously recirculating the CO2 gas without its release from the system; andaccelerating absorption and mass transfer of CO2 into the absorbent by providing the liquid absorbent in the form of droplets by spraying the liquid absorbent into the absorber such that the gas exiting the expansion machine can be in contact with a large surface constituted by the plurality of absorbent droplets, the droplets having a diameter of between 5 mm and 0.01 mm. 2. The method as claimed in claim 1, wherein the droplets have a diameter of between 2 mm and 0.025 mm. 3. The method as claimed in claim 1, wherein the droplets have a diameter of between 0.5 mm 0.05 mm. 4. The method as claimed in claim 1, wherein the droplets have a diameter of between 0.25 mm and 0.1 mm. 5. The method as claimed in claim 1, wherein the at least one heat source (1) provides thermal energy at up to 120° C. 6. The method as claimed in claim 1, wherein the transferring step comprises transferring thermal energy from the at least one external heat source directly to the reactor (7). 7. A method for producing electrical energy using an essentially closed loop system comprising the steps of: providing a reactor (7);accessing at least one external heat source (1) for providing thermal energy to the essentially closed loop system, the at least one external heat source being a low temperature heat source providing thermal energy at up to 150° C.;transferring thermal energy from the at least one external heat source to the reactor (7);selecting the heat source (1) from the group consisting of solar energy, waste heat from power plants or industrial processes, waste heat from motors or engines, geothermal heat, heat from combustion of organic materials, and waste heat from high temperature power generation cycles;providing an absorber system (3) for chemically absorbing carbon dioxide (CO2) into an absorbent liquid to provide a mix of CO2 gas and liquid absorbent (gas-absorbent mix) and to generate a low pressure;providing at least one pump device (6) for increasing the pressure of said gas-absorbent mix and allowing transfer of pressurized gas-absorbent mix to the reactor (7);providing a separator downstream of the pump device for separating said gas-absorbent mix and recycling part of said gas-absorbent mix to said absorber system;using thermal energy from the said heat source (1) to heat the pressurized gas-absorbent mix at the reactor, thereby splitting the pressurized gas-absorbent mix into a heated and pressurized CO2 gas and a heated absorbent liquid as output of the reactor; —providing an expansion machine (15) with a generator (23) for producing electricity by expanding the heated and pressurized CO2 gas from the said reactor (7) into a low temperature CO2 gas by using the low pressure generated in the said absorber system (3);providing a pipe system that leads the said heated absorbent liquid exiting the reactor (7) and the low temperature CO2 gas exiting the expansion machine (15) to the said absorber system (3) so the CO2 gas is chemically re-absorbed into the heated absorbent liquid for the process to staff over in a reversible reaction with the CO2 gas absorbed into the heated absorbent liquid in said absorber system (3);using said heated and pressurized CO2 gas to operate said expansion machine within a temperature interval between −78° C. and plus 150° C.,using in the absorber system a material capable of binding CO2, —obtaining a CO2 pressure in said reactor of between 20 bar and MOS bar,obtaining a CO2 pressure in said absorber system of between 0.5 bar and 0.001 bar, andthe closed loop system continuously recirculating the CO2 gas without its release from the system. 8. The method as claimed in claim 7, wherein the gas-absorbent mix is operable between −70° C. and 150° C. 9. The method as claimed in claim 8, wherein the gas-absorbent mix is operable between −30° C. and 140° C. 10. The method as claimed in claim 8, wherein the gas-absorbent mix is operable between −10° C. and 130° C. 11. The method as claimed in claim 8, wherein the gas-absorbent mix is operable between 0° C. and 100° C. 12. The method as claimed in claim 7, further comprising the steps of: transferring heat using a heat exchange system (12) from the heated absorbent liquid from the reactor (7) to the gas-absorbent mix before the gas-absorbent mix enters the reactor (7); andproviding a thermal energy storage unit (2) for storing the gas-absorbent mix to provide thermal energy to supplement or replace heat from the heat source. 13. The method as claimed in claim 7, further comprising the step of: providing a booster system (19) for heating the heated and pressurized gas by said heat source or a secondary heat source, operating at least at the same temperature as the gas-absorbent mix, after or at a downstream section of the reactor (7) and before entering the expansion machine (15). 14. The method as claimed in claim 7, further comprising the step of: adding at least one chemical in order to reduce the freezing point of the gas-absorbent mix, for adjustment of viscosity or crystallization or for enabling transport of a slurry containing the gas-absorbent mix, said chemical being selected from the group of water, alcohol, oil, silicone oil and defoamer. 15. The method as claimed in claim 7, wherein the gas-absorbent mix includes an absorbent selected from the group consisting of at least one nitrogen-containing chemical compound. 16. The method as claimed in claim 15, wherein the absorbent is selected from the group consisting of DEA (diethanolamine), MEA (monoethanol-amine), morpholine, piperazine, MDEA (methyldiethanolamine), DGA (diglycolamine), DIPA (diisopropanolamine), TEA (triethanolamine) alone or mixed with water or alcohols, lipophilic amines including dialkylamines where alkyl may be methyl, ethyl, and preferably propyl, butyl, sec-butyl and iso-butyl, pentyl, hexyl or alkyl groups with more than six C atom, mixtures thereof including biphasic and thermomorphic amine mixtures, amines coupled to zeolites or silicas, including mixtures with water and/or alcohols such as butanol, hexanol and glycols, aminosilicones, guanidine, amidine, aminoacid derivatives, ionic liquids, alone or in combination with freezing point depressants or chemicals which allow a cold slurry to be transported by mechanical means, including silicone oils, and where the amines have lower absorption enthalpies for the CO2-amine reaction than MEA (monoethanolamine) and have boiling points at 1 bar above 120° C. 17. The method as claimed in claim 15, wherein said nitrogen-containing compound comprises NH3 or amine. 18. The method as claimed in claim 7, comprising at least one of the following: the cold temperature of the CO2 exiting the turbine is used for condensing water or making ice to produce fresh water or supply cooling for freezer applications; andthe excess heat generated in the system provides residential hot water or is used for pre-heating the thermal fluid collecting solar heat at least during part of the operation of the system to achieve a faster start-up. 19. The method as claimed in claim 7, wherein the gas-absorbent mix is subjected to a separation step selected from phase separation, decanting and centrifuging, and wherein the gas-absorbent mix is split into at least two fractions of which the fraction which is richest in CO2 is transferred to the reactor for splitting into CO2 gas and lean absorbent. 20. The method as claimed in claim 7, wherein the gas-absorbent mix is cooled. 21. The method as claimed in claim 7, wherein at least a fraction of the gas-absorbent mix is transferred back to the absorber system (3), in order to achieve a higher loading level. 22. A system according to claim 7 for production of electrical energy. 23. The method as claimed in claim 7, wherein the temperature interval is between −70° C. and plus 140° C. 24. The method as claimed in claim 7, wherein the obtained CO2 pressure in said reactor is between 15 bar and 0.8 bar. 25. The method as claimed in claim 7, wherein the obtained CO2 pressure in said reactor is between 10 bar and 1.2 bar. 26. The method as claimed in claim 7, wherein the CO2 pressure obtained in said absorption system is between 0.3 bar and 0.002 bar. 27. The method as claimed in claim 7, wherein the CO2 pressure obtained in said absorption system is between 0.15 bar and 0.005 bar. 28. The method as claimed in claim 7, wherein the CO2 pressure obtained in said absorption system is between 0.1 bar and 0.01 bar. 29. The method as claimed in claim 7, wherein said material capable of binding CO2 is capable of binding by physical van-der-Waals forces or chemical bonds. 30. The method as claimed in claim 7, wherein the at least one heat source (1) provides thermal energy at up to 120° C. 31. The method as claimed in claim 7, wherein the transferring step comprises transferring thermal energy from the at least one external heat source directly to the reactor (7). 32. The method as claimed in claim 7, wherein the expansion machine providing step comprises: —providing said expansion machine (15) with said generator (23) for producing electricity by expanding only the heated and pressurized CO2 gas from the said reactor (7) into a low temperature CO2 gas by using the low pressure generated in the said absorber system (3).