CO2 capture system, power generation equipment

Abstract

To suppress energy burden and perform separation recovery of CO2, and to effectively utilize CO2.SOLUTION: A CO2 recovery system comprises: CO2 retaining means 11 which holds CO2 in exhaust gas and atmosphere, and dissipates retained CO2 by use of heat energy; and electrolytic reduction means 12 which uses CO2 dissipated from the CO2 retaining means 11, and for example, generates CO(C) accompanied by heat generation. For example, heat (Joule heat) from the electrolytic reduction means 12, that is generated when CO(C) is produced is supplied to the CO2 retaining means to release CO2, and the released CO2 is fed to the electrolytic reduction means 12.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a CO2 recovery system for separating and recovering CO2, and a power generation facility equipped with the CO2 recovery system.

Background Art

[0002] Coal exists in a wide area of the world, has a large recoverable reserve, and a stable price. Therefore, it has high supply stability and a low price per calorific value. Coal is used, for example, as fuel for a power generation boiler (for example, Patent Document 1), and stable power supply is realized by power generation using coal.

[0003] On the other hand, when using fossil fuels, the generation of CO2 is inevitable at present. For this reason, various measures have been taken to suppress CO2 emissions, such as separating and recovering CO2 and performing isolation treatment. When separating and recovering CO2, for example, thermal energy such as steam for power generation is required, and for CO2 isolation, it is necessary to consider a decrease in power generation output and handling, or to consider a transport route and a storage location.

[0004] As described above, in fact, various devices have been made regarding suppressing CO2 emissions, and it is desired to establish a technology for suppressing the energy burden, separating and recovering CO2, and effectively using the separated and recovered CO2.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention has been made in view of the above circumstances, and aims to provide a CO2 capture system that can separate and recover CO2 while suppressing the energy burden and effectively utilize CO2, and a power generation facility equipped with the CO2 capture system. [Means for solving the problem]

[0007] The CO2 recovery system of the present invention according to claim 1, for achieving the above objective, A CO2 retention means that retains CO2 in the gas and releases the retained CO2 by thermal energy, A valuable substance generating means that uses the CO2 released from the CO2 retention means to generate a valuable substance accompanied by heat generation, The CO2 storage means comprises a supply means that supplies the heat generated when the valuable substance is produced in the valuable substance production means as thermal energy to the CO2 storage means, The aforementioned CO 2 The holding means is, CO in exhaust gases and / or in the atmosphere 2 It is a means of holding, The means for generating valuable materials is, CO 2 A first electrolysis means for obtaining the aforementioned valuable substance from CO, and a chemical reaction that generates heat 2 , and H 2 A chemical reaction means for obtaining the aforementioned valuable substance from, The aforementioned CO 2 In the holding means, the CO is held by the Joule heat generated in the first electrolysis means and the chemical reaction means. 2 It is emitted, The first electrolysis means and the chemical reaction means are arranged in parallel, and the first electrolysis means and the chemical reaction means contain the CO 2 CO emitted from the holding means 2 It is distributed and supplied, Furthermore, H 2 By electrolysis of O, H used in the reaction of the chemical reaction means 2 Having a second electrolysis means to obtain It is characterized by the following:

[0008] In the present invention according to claim 1, CO2 in a gas such as exhaust gas or atmosphere is retained by the CO2 retention means, and heat generated when a valuable substance is produced by the valuable substance production means is sent from the supply means (including heat storage) to the CO2 retention means, and the retained CO2 is released and sent to the valuable substance production means. And as a gas, CO is present in exhaust gases and the atmosphere. 2 CO 2 The CO2 held by the holding means 2 It is released and sent to a means for producing valuable materials. Furthermore, using the first electrolysis method, the Joule heat generated during the electrochemical reaction is recovered, and the recovered heat is converted to CO2. 2 CO 2 CO is used as a heat source that releases CO 2 Valuable materials can be obtained from this. For example, CO2 can be added to an electrolyte solution in which a reducing electrode (cathode) and an oxygen-evolving electrode (anode) are immersed. 2 By blowing in a current and passing an electric current through it, for example, C and CO can be recovered as valuable materials. Furthermore, using chemical reaction means, the heat generated by the chemical reaction (heat of reaction) is recovered, and the recovered heat is converted into CO2 2 CO 2 CO is used as a heat source that releases CO 2 , and H 2 For example, CH 4 It can be recovered as a valuable resource. Furthermore, the second electrolysis means generates H used in the chemical reaction means. 2 This can be obtained. Furthermore, if the electrolysis by the second electrolysis means generates heat, the Joule heat generated by the second electrolysis means is recovered, and the recovered heat is used to produce CO 2 CO 2 It can assist in providing a heat source that releases heat.

[0009] Therefore, CO2 held by the CO2 holding means can be released in a state where external energy is reduced and sent to the valuable substance generating means to generate valuable substances. Accordingly, it becomes possible to suppress the energy burden, separate and recover CO2, and effectively utilize CO2.

[0012] Also, Claim 2 the CO2 recovery system of the present invention according to Claim 1 is characterized in that in the CO2 recovery system described in , the CO2 holding means is a means having a chemical absorbent that absorbs CO2 by a chemical reaction.

[0013] Claim 2 In the present invention according to , CO2 can be separated and recovered by a chemical reaction between CO2 and a chemical absorbent (for example, amine). By using a chemical absorbent, a large amount of CO2 can be absorbed even when the partial pressure of CO2 in the gas is low.

[0014] Also, Claim 3 the CO2 recovery system of the present invention according to Claim 1 is characterized in that in the CO2 recovery system described in , the CO2 holding means is a means having a solid absorbent that absorbs CO2.

[0015] Claim 3 In the present invention according to , CO2 can be separated and recovered by a chemical reaction between CO2 and a solid absorbent (for example, a porous material having an amine supported on a porous carrier).

[0022] Also , book The CO2 capture system of the invention is As mentioned above In the CO2 recovery system, the means for generating valuable materials includes a third electrolysis means for obtaining CO and H2 from CO2 and H2O through an electrochemical reaction accompanied by heat generation. It is preferable.

[0023] As a result, The third electrolysis means can obtain CO and H2 as valuable materials from CO2 and H2O. The Joule heat generated by the third electrolysis means can be recovered and used as a heat source to release CO2 from the CO2 retention means.

[0024] Also , book The CO2 capture system of the invention is As mentioned above In the CO2 recovery system, the valuable substance generation means includes a second chemical reaction means that obtains a valuable substance from the CO and H2 obtained by the third electrolysis means through an exothermic chemical reaction. It is preferable.

[0025] As a result, The CO and H2 obtained by the third electrolysis means can be used to recover valuable substances, such as CH4, methanol:CH3OH, and liquid hydrocarbons through FT synthesis, through an exothermic chemical reaction. The heat generated by the chemical reaction in the second chemical reaction means (heat of reaction) can be recovered and used as a heat source to release CO2 from the CO2 retention means.

[0026] Furthermore, in order to achieve the above objectives Claim 4 The power generation equipment of the present invention relates to a boiler that burns fuel to generate steam, a turbine that expands the steam generated in the boiler to obtain driving force and generate electricity, and an exhaust gas discharge means for releasing exhaust gas from the boiler. Claims 1 to 3 The CO2 recovery system comprises the CO2 recovery system described in any one of the above, wherein the CO2 holding means of the CO2 recovery system holds CO2 in the exhaust gas released from the exhaust gas release means.

[0027] Claim 4In the present invention relating to this invention, exhaust gas from a boiler is released from an exhaust gas discharge means, CO2 in the exhaust gas is held by a CO2 holding means, heat generated when valuable materials are produced by a valuable materials production means is sent from a supply means (including heat storage) to the CO2 holding means, and the held CO2 is released and sent to the valuable materials production means.

[0028] Therefore, with reduced external energy consumption, the CO2 held by the CO2 retention means can be released and sent to the valuable material production means to generate valuable materials. Consequently, it becomes possible to create a power generation facility that can separate and recover CO2 while suppressing the energy burden and effectively utilize the CO2.

[0029] Furthermore, electricity derived from renewable energy sources (heat obtained from electricity) can be used as the energy source for the first electrolysis means, second electrolysis means, third electrolysis means, and chemical reaction means and second chemical reaction means described above. [Effects of the Invention]

[0030] The CO2 recovery system of the present invention enables the separation and recovery of CO2 while suppressing the energy burden, and makes it possible to utilize CO2 effectively.

[0031] Furthermore, the power generation equipment of the present invention can be equipped with a CO2 recovery system that suppresses the energy burden, separates and recovers CO2, and effectively utilizes the CO2. [Brief explanation of the drawing]

[0032] [Figure 1] This is a schematic diagram of a power generation facility equipped with a CO2 recovery system according to one embodiment of the present invention. [Figure 2] This is a schematic diagram of a CO2 recovery system according to one embodiment of the present invention. [Figure 3] This is a conceptual diagram of an electrolytic reduction method. [Figure 4] This is a schematic diagram of a CO2 recovery system according to another embodiment of the present invention. [Figure 5]This is a schematic diagram of a CO2 recovery system according to another embodiment of the present invention. [Modes for carrying out the invention]

[0033] Figure 1 shows a schematic diagram illustrating the overall configuration of a power generation facility (coal-fired power generation facility) equipped with a CO2 recovery system according to one embodiment of the present invention.

[0034] As shown in the diagram, the power generation facility (thermal power generation facility) 1 is equipped with a boiler 2 that uses coal as fuel to produce steam (high-pressure steam). The steam generated in the boiler 2 is expanded and driven by a steam turbine 3, and power is generated by driving the steam turbine 3. The combustion exhaust gas (exhaust gas) from the boiler 2 has impurities removed in the exhaust gas treatment device 4 and is sent to the CO2 recovery system 5 (exhaust gas release means). In the CO2 recovery system 5, CO2 in the exhaust gas from which impurities have been removed is recovered to produce valuable materials, and the exhaust gas from which CO2 has been recovered is released into the atmosphere.

[0035] Furthermore, the CO2 capture system 5 can receive exhaust gases containing other CO2, such as exhaust gases from internal combustion engines, in addition to the exhaust gas from boiler 2.

[0036] The CO2 capture system will be explained based on Figures 2 and 3.

[0037] Figure 2 shows the overall schematic configuration of a CO2 recovery system according to one embodiment of the present invention, and Figure 3 shows a schematic conceptual situation illustrating an example of the configuration of an electrolytic reduction means.

[0038] As shown in Figure 2, the CO2 recovery system 5 includes a CO2 retention means 11 that introduces exhaust gas, retains CO2 in the exhaust gas, and releases the retained CO2 using thermal energy.

[0039] Furthermore, it is also possible to introduce air into the CO2 retention means 11 and retain CO2 from the atmosphere as well. Alternatively, it is also possible to retain only CO2 from the atmosphere in the CO2 retention means 11.

[0040] The CO2 retention means 11 has a chemical absorbent (e.g., an amine) that absorbs CO2 through a chemical reaction. CO2 is separated and recovered through a chemical reaction between CO2 and the chemical absorbent (e.g., an amine). By using a chemical absorbent (e.g., an amine), a large amount of CO2 can be absorbed even when the partial pressure of CO2 in the gas is low.

[0041] As a means of retaining CO2, it is also possible to use a means that has a solid absorbent material that absorbs CO2. As the solid absorbent material, for example, a porous material in which an amine is supported on a porous carrier can be used to absorb CO2.

[0042] The CO2 recovery system 5 includes an electrolytic reduction means 12, which is a first electrolysis means that generates valuable substances from CO2, for example, CO(C), as a valuable substance by an electrochemical reaction using CO2 released from the CO2 holding means 11, and generates valuable substances with heat. Using the electrolytic reduction means 12, CO(C), for example, can be obtained from CO2 by an electrochemical reaction.

[0043] Furthermore, CO(C) is not the only valuable substance that can be obtained from CO2 through electrochemical reactions.

[0044] In the electrolytic reduction means 12, for example, the heat generated when CO(C) is produced is stored in the heat storage means 13, and the heat stored in the heat storage means 13 is supplied as thermal energy for releasing the CO2 held in the CO2 holding means 11 (supply means). It is also possible to configure a supply means that directly supplies the heat generated when CO(C) is produced in the electrolytic reduction means 12, for example, without using the heat storage means 13.

[0045] As shown in Figure 3, the electrolytic reduction means 12 has an oxygen-generating electrode (anode) 15 from which electrons are removed and an oxidation reaction occurs, and a reducing electrode (cathode) 16 from which electrons are given and a reduction reaction occurs. CO2 dissolved in the electrolyte is reduced at the reducing electrode (cathode) 16, and a valuable substance, such as CO(C), is produced with exothermic heating due to Joule heating.

[0046] In the CO2 recovery system 5 described above, CO2 from the exhaust gas and atmosphere is retained by the CO2 retention means 11, and the heat generated when CO(C) is produced, for example, is sent to the CO2 retention means 11 by the electrolytic reduction means 12. Then, the CO2 retained in the CO2 retention means 11 is released by the thermal energy generated by the heat produced by the electrolytic reduction means 12.

[0047] Therefore, with reduced external energy consumption, the CO2 held in the CO2 retention means 11 is released and sent to the electrolytic reduction means 12, where, for example, CO(C) can be generated. Consequently, it becomes possible to separate and recover CO2 from exhaust gas and the atmosphere while suppressing the energy burden, and to utilize the CO2 effectively.

[0048] Furthermore, by reducing the external energy consumption, the CO2 held in the CO2 retention means 11 can be released and sent to the valuable material production means to produce valuable materials, thereby enabling the power generation equipment 1 to separate and recover CO2 while suppressing the energy burden and effectively utilizing the CO2.

[0049] Other embodiments of the CO2 recovery system will be described based on Figures 4 and 5. Figures 4 and 5 show a schematic configuration of a CO2 recovery system according to another embodiment of the present invention. Components identical to those shown in Figure 2 are denoted by the same reference numerals.

[0050] The CO2 recovery system 21 shown in Figure 4 includes a CO2 retention means 11 that introduces exhaust gas, retains CO2 in the exhaust gas, and releases the retained CO2 using thermal energy.

[0051] The CO2 recovery system 21 includes a valuable substance generation means 22 that uses CO2 released from the CO2 retention means 11 to generate valuable substances with heat. The valuable substance generation means 22 includes an electrolytic reduction means 12 that generates (obtains) CO(C) from CO2 by an electrochemical reaction with heat, and a chemical reaction means 23 that obtains CH4 as a valuable substance from CO2 and H2 by a chemical reaction with heat. Furthermore, it includes a second electrolysis means 24 that obtains H2 used in the reaction of the chemical reaction means 23 by electrolysis of H2O (with heat).

[0052] Furthermore, the H2 used in the reaction of the chemical reaction means 23 can also be supplied from an external source.

[0053] In the electrolytic reduction means 12, for example, heat (Joule heat) generated when CO(C) is produced; in the chemical reaction means 23, for example, heat (reaction heat) generated when CH4 is produced; and in the second electrolysis means 24, heat (Joule heat) generated when H2 is produced are stored in the heat storage means 13. The heat stored in the heat storage means 13 is supplied as thermal energy to release the CO2 held in the CO2 holding means 11 (supply means).

[0054] In the CO2 recovery system 21 with the above configuration, for example, CO(C) can be obtained by the electrolytic reduction means 12, and for example, CH4 can be obtained from CO2 and H2 by the chemical reaction means 23. Furthermore, the H2 used in the reaction of the chemical reaction means 23 can be obtained by the second electrolysis means 24, and the heat (Joule heat) generated by the second electrolysis means 24 can be recovered and used as a heat source to support the release of CO2 from the CO2 retention means 11.

[0055] The CO2 recovery system 31 shown in Figure 5 includes a CO2 retention means 11 that introduces exhaust gas, retains CO2 in the exhaust gas, and releases the retained CO2 using thermal energy.

[0056] The CO2 recovery system 31 includes a valuable substance generation means 32 that uses the CO2 released from the CO2 holding means 11 to generate valuable substances with heat. The valuable substance generation means 32 includes a third electrolysis means 33 that obtains CO and H2 as valuable substances from CO2 and H2O through an electrochemical reaction with heat, and a second chemical reaction means 34 that obtains methanol (CH3OH) as a valuable substance from the CO and H2 obtained in the third electrolysis means 33 through an electrochemical reaction with heat.

[0057] The heat generated when CO and H2 are produced in the third electrolysis means 33 (Joule heat), and the heat generated when CH3OH is produced in the second chemical reaction means 34 (reaction heat) are stored in the heat storage means 13, and the heat stored in the heat storage means 13 is supplied as thermal energy to release the CO2 held in the CO2 holding means 11 (supply means).

[0058] In the CO2 recovery system 31 with the above configuration, the third electrolysis means 33 is used to obtain CO and H2 from CO2 and H2O, and from the obtained CO and H2, a chemical reaction that generates heat can be used to obtain, for example, CH3OH.

[0059] Furthermore, it is possible to obtain CH4 as a valuable substance using the CO and H2 obtained in the third electrolysis means 33, or to obtain liquid hydrocarbons as a valuable substance through FT synthesis.

[0060] The CO2 capture system described above enables the separation and recovery of CO2 while reducing the energy burden, making it possible to utilize CO2 effectively. Furthermore, the power generation equipment described above can be equipped with a CO2 capture system that reduces the energy burden, separates and recovers CO2, and makes effective use of CO2. [Industrial applicability]

[0061] This invention can be used in the industrial sector for CO2 capture systems. [Explanation of Symbols]

[0062] 1. Power generation facilities (thermal power generation facilities) 2 Boilers 3 Steam Turbine 4. Exhaust gas treatment device 5, 21, 31 CO2 Capture System 11 CO2 retention means 12 Electrolytic reduction method 13 Heat storage means 15. Oxygen-generating electrode (anode) 16. Reduction electrode (cathode) 22, 32 Means for generating valuable materials 23 Chemical reaction means 24 Second electrolysis means 33 Third electrolysis means 34 Second chemical reaction means

Claims

1. CO in gas ２ It retains the retained CO ２ CO2 is released by thermal energy. ２ Holding means and The aforementioned CO ２ CO emitted from the holding means ２ A means for generating valuable materials that generates valuable materials with heat, The heat generated when the valuable substance is produced in the valuable substance production means is used as the thermal energy for the CO ２ It comprises a supply means for supplying to a holding means, The CO2 retention means is A means for retaining CO2 in exhaust gas and / or in the atmosphere, The means for generating valuable materials is, A first electrolysis means for obtaining the valuable substance from CO₂ by an electrochemical reaction accompanied by heat generation, and a chemical reaction means for obtaining the valuable substance from CO₂ and H₂ by a chemical reaction accompanied by heat generation, In the CO2 retention means, the CO2 retained by the Joule heat generated in the first electrolysis means and the chemical reaction means is released. The first electrolysis means and the chemical reaction means are arranged in parallel, and CO2 released from the CO2 retention means is distributed and supplied to the first electrolysis means and the chemical reaction means. Furthermore, the system includes a second electrolysis means for obtaining H₂O to be used in the reaction of the chemical reaction means by electrolysis of H₂O. CO, characterized by ２ Collection system.

2. The CO2 described in Claim 1 ２ In the collection system, the CO ２ The holding means is CO ２ This means has a chemical absorbent that absorbs by a chemical reaction. CO, characterized by ２ Collection system.

3. The CO2 described in Claim 1 ２ In the collection system, The aforementioned CO ２ The holding means is, CO ２ This means has a solid absorbent material that absorbs moisture. CO, characterized by ２ Collection system.

4. A boiler that burns fuel to generate steam, A turbine that generates electricity by expanding the steam produced in the boiler to obtain driving force, An exhaust gas discharge means for releasing exhaust gas from the boiler, CO according to any one of claims 1 to 3 ２ Equipped with a collection system, The aforementioned CO ２ The CO2 recovery system ２ The holding means includes: CO in the exhaust gas released from the exhaust gas discharge means ２ is retained A power generation facility characterized by the following features.

Images