A carbon dioxide capture system for power generation using waste heat temperature difference

Abstract

The present invention discloses a carbon dioxide capture system that utilizes waste heat temperature difference for power generation, which includes a thermoelectric power generation device and a carbon dioxide capture device connected to each other. The carbon dioxide capture device includes a number of parallel-connected carbon dioxide capture units. Each carbon dioxide capture unit includes an electrolytic cell, a piston container, and a gas cylinder connected in sequence. High-temperature waste gas is cooled after passing through the thermoelectric power generation device and then enters the electrolytic cell. A reduction potential is applied to the working electrode of the electrolytic cell to absorb carbon dioxide in the waste gas, and then an oxidation potential is applied to release carbon dioxide into the piston container. Carbon dioxide is injected from the piston container into the gas cylinder. The thermoelectric power generation device supplies power to the electrolytic cell. The present invention utilizes the waste heat of industrial waste gas for thermoelectric power generation, provides electrical energy for the capture device and the control system, and takes into account the cooling requirement of the waste gas flow in the electrochemical process during capture.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide recovery, and in particular relates to a carbon dioxide capture system for generating electricity using the temperature difference of exhaust gas. Background Art

[0002] Global warming is one of the most direct manifestations of the intensification of the greenhouse effect, which has led to hazards such as rising sea levels, retreating glaciers, and early melting of rivers. The carbon dioxide contained in the exhaust gas generated by the combustion of fossil fuels is considered to be the main cause of the intensification of the greenhouse effect. Responding to climate change and reducing carbon emissions has become a hot topic internationally.

[0003] The capture system of the widely used traditional chemical adsorbent (such as monoethanolamine) carbon dioxide recovery technology is usually arranged with an absorption tower, a regeneration tower, a washing chamber, a condensate pipeline, a washing water pipeline, etc., which has the defects of complex pipelines and large container volume, and it is difficult to eliminate the loss of carbon dioxide in the recovery process.

[0004] The principle of electrochemical capture of carbon dioxide is to use quinones as carriers in a suitable solvent phase (organic solvent or ionic liquid). When a reduction potential is applied to quinones, CO2 can easily combine with them to form a stable [Q-CO2] 2－ adduct; adduct already formed [Q-CO2] 2－ When an oxidative potential is applied, the previously bound CO2 can be easily released.

[0005] However, electrochemical recovery of carbon dioxide technology usually requires the control of the gas temperature in the process to make it suitable for the electrochemical process. This temperature is often much lower than the temperature of direct exhaust gas from industrial production. In addition, increasing the binding and release rate of carbon dioxide in the electrochemical process is also one of the keys to promoting the development of electrochemical capture of carbon dioxide technology. Summary of the invention

[0006] In response to the above problems and needs, the present invention proposes a carbon dioxide capture system that uses waste gas temperature difference to generate electricity. For industrial waste gas, the system uses temperature difference to generate electricity to power the capture device and cool the waste gas, while achieving lossless automatic capture of carbon dioxide into a directly usable gas product in a compact space. In addition, the capture system effectively increases the rate at which carbon dioxide is released from the electrolytic cell during the electrochemical process.

[0007] In order to achieve the above object, the present invention provides a carbon dioxide capture system for generating electricity using waste gas temperature difference, comprising a connected temperature difference power generation device and a carbon dioxide capture device, wherein the carbon dioxide capture device comprises a plurality of carbon dioxide capture units connected in parallel, and the carbon dioxide capture unit comprises an electrolytic cell, a piston container and a gas cylinder connected in sequence;

[0008] The high-temperature waste gas is cooled after passing through the thermoelectric power generation device and then enters the electrolytic cell. A reduction potential is applied to the working electrode of the electrolytic cell to absorb carbon dioxide in the waste gas, and then an oxidation potential is applied to release carbon dioxide into the piston container; the carbon dioxide is injected into the gas cylinder from the piston container;

[0009] The thermoelectric power generation device supplies power to the electrolytic cell.

[0010] Preferably, the electrolytic cell includes an auxiliary electrode and an electrolyte for providing and collecting electrons for the electrochemical reaction in the capture process.

[0011] Preferably, the piston container includes an electronically controlled piston mechanism driven by a motor and a pressure sensor for monitoring the pressure inside the piston container.

[0012] Preferably, an electromagnetic three-way valve is provided between the electrolytic cell, the piston container and the gas cylinder.

[0013] Preferably, the electrolytic cell includes a gas flow inlet pipe and a gas flow outlet pipe for the inlet and outlet of the waste gas.

[0014] Preferably, the gas flow inlet pipe is provided with an inlet pipe solenoid valve, and the gas flow outlet pipe is provided with an outlet pipe solenoid valve.

[0015] Preferably, the gas cylinder includes a gas cylinder port solenoid valve.

[0016] The technical effects of the present invention:

[0017] The present invention utilizes the waste heat of industrial waste gas for thermoelectric power generation, provides electrical energy for the capture device and the control system, and takes into account the cooling requirement of the waste gas flow in the electrochemical process of capture. At the same time, the compact system can achieve lossless capture of carbon dioxide released in the electrochemical process. In addition, the capture system always maintains a negative pressure in the collection environment through automatic control, effectively increasing the release rate of carbon dioxide from the electrolytic cell in the electrochemical process and improving the overall capture rate. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the carbon dioxide capture system provided by the present invention.

[0019] Figure 2 It is a schematic diagram of the thermoelectric power generation device provided by the present invention.

[0020] Figure 3 It is a schematic diagram of the structure of the carbon dioxide capture unit provided by the present invention.

[0021] Figure 4 It is a working flow chart of the carbon dioxide capture system provided by the present invention.

[0022] Figure 5This is a schematic diagram of various working stages of the carbon dioxide capture unit provided by the present invention.

[0023] In the figure, 10-temperature difference power generation device, 11A-exhaust gas flow channel inlet pipe, 11B-exhaust gas flow channel outlet pipe, 12-exhaust gas flow chamber, 13-temperature difference power generation plate, 14-heat dissipation thorn plate, 15-cooling water tank, 16A-positive electrode wire, 16B-negative electrode wire, 17-energy storage power supply device, 20-carbon dioxide capture device, 21A-gas flow channel inlet pipe, 21B-gas flow channel outlet pipe, 22A-gas flow channel inlet pipe solenoid valve, 22B-gas flow channel outlet pipe solenoid valve, 23A-working electrode, 23B-electrolyte, 23C-auxiliary electrode, 24-piston container, 25-electrically controlled piston mechanism, 26-piston container pressure sensor, 27-electromagnetic three-way valve, 28-gas cylinder mouth solenoid valve, 29-gas cylinder. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The principle of electrochemical capture of carbon dioxide is to use quinones as carriers in a suitable solvent phase (organic solvent or ionic liquid). When a reduction potential is applied to quinones, CO2 can easily combine with them to form a stable [Q-CO2] 2－ adduct; adduct already formed [Q-CO2] 2－ When an oxidative potential is applied, the previously bound CO2 can be easily released.

[0026] The forward process of this reversible reaction is: CO2 first dissolves in the electrolyte, and the quinone substance to which the reduction potential is applied obtains electrons to form quinone anions (Q ·－ ) and quinone dianion (Q 2－ ) followed by the quinone dianion (Q 2－ ) combines with CO2 dissolved in the electrolyte to form an adduct [Q-CO2] 2－ .

[0027] The chemical reaction is shown below:

[0028]

[0029] like Figure 1 and Figure 2As shown in the figure, the carbon dioxide capture system provided by the present invention comprises a thermoelectric power generation device 10 and a carbon dioxide capture device 20 which are connected. High-temperature waste gas enters through the waste gas flow channel inlet pipe 11A, passes through the waste gas flow chamber 12, and is cooled under the action of the thermoelectric power generation chips 13, heat dissipation fin chips 14 and the cooling water tank 15. After the temperature drops to the requirement of the carbon dioxide capture device 20, it flows out through the waste gas flow channel outlet pipe 11B for use by the carbon dioxide capture device 20. At the same time, the thermoelectric power generation chips 13 generate electricity using the temperature difference on both sides thereof, and the electric energy is transmitted to the energy storage power supply device 17 for storage through the positive wire 16A and the negative wire 16B connecting the thermoelectric power generation chips and the energy storage device for use by the carbon dioxide capture device 20. The flow channel of the waste gas flow chamber 12 is in an S shape. Both sides of the thermoelectric power generation chips 13 are closely connected to the waste gas flow chamber 12 and the heat dissipation fin chips 14. The heat dissipation fin chips 14 are inserted into the interior of the cooling water tank 15, which is conducive to achieving the purposes of cooling and power generation.

[0030] As Figure 1 and Figure 3 shown in the figure, the carbon dioxide capture device 20 includes a plurality of parallel carbon dioxide capture units. Each carbon dioxide capture unit includes an electrolytic cell, a piston container 24 and a gas cylinder 29 which are connected in sequence. The cooled waste gas enters the electrolytic cell through the gas flow channel inlet pipe 21A. The electrolytic cell includes a working electrode 23A, an electrolyte 23B and a counter electrode 23C. The counter electrode 23C provides electrons and collects electrons for the chemical reaction during the capture process. The electrolyte solution includes quinone substances. A reduction potential is applied to the working electrode 23A of the electrolytic cell to absorb carbon dioxide in the waste gas, and then an oxidation potential is applied to release carbon dioxide into the piston container 24; the carbon dioxide is injected into the gas cylinder 29 from the piston container 24.

[0031] The piston container 24 includes an electronically controlled piston mechanism 25 and a piston container pressure sensor 26. When the electrolytic cell releases carbon dioxide and injects carbon dioxide into the gas cylinder 29, the piston container 24 can collect the carbon dioxide released by the electrolytic cell each time and increase the reaction rate of the electrolytic cell. When the electrolytic cell releases carbon dioxide, the pressure sensor 26 monitors the internal air pressure of the piston container 24 in real time and controls the rising rate of the electronically controlled piston mechanism 26, so that the internal air pressure of the piston container 24 is always lower than the electrolytic cell ambient pressure by a certain level, thereby accelerating the mass transfer rate of carbon dioxide release and thus increasing the overall reaction rate of the electrolytic cell. The gas cylinder port solenoid valve 28 and the gas cylinder 29 are enabled when the electrolytic cell absorbs carbon dioxide in the waste gas or the electrolytic cell stops working, and serve to finally collect the carbon dioxide captured in the piston container 24 to form an industrial product. The carbon dioxide capture device 20 formed by a plurality of parallel carbon dioxide capture units can perform time difference control on each unit, so that each unit is enabled in a two-group cross sequence, so that each capture unit is not idle, and at the same time, the waste gas is fully utilized to capture carbon dioxide.

[0032] As Figure 4and Figure 5 As shown, the working process of the carbon dioxide capture system provided by the present invention includes:

[0033] Stage 0 (waste gas cooling and thermoelectric power generation stage): The high-temperature waste gas enters the waste gas flow channel inlet pipe 11A and the waste gas flow chamber 12, and is cooled under the combined action of the thermoelectric generation chip 13, the heat dissipation fin 14 and the cooling water tank 15, and then enters the carbon dioxide capture device 20 through the waste gas flow channel outlet pipe 11B. At the same time, the thermoelectric generation chip 13 generates electricity using the temperature difference on both sides, and transmits the electric energy to the energy storage and power supply device 17 for storage through the positive wire 16A and the negative wire 16B connecting the thermoelectric generation chip and the energy storage device, for use by each carbon dioxide capture unit in the carbon dioxide capture device 20.

[0034] Stage 1 (carbon dioxide binding stage): The solenoid valve 22A of the gas flow channel inlet pipe is opened, and the waste gas enters the electrolytic cell through the gas flow channel inlet pipe 21A. A reduction potential is applied to the working electrode 23A of the electrolytic cell, and the carbon dioxide in the waste gas is absorbed. The solenoid valve 22B of the gas flow channel outlet pipe is opened, and other waste gases are discharged through the gas flow channel outlet pipe 21B.

[0035] Stage 2 (carbon dioxide release stage): The solenoid valve 22A of the gas flow channel inlet pipe and the solenoid valve 22B of the gas flow channel outlet pipe are closed, and the electromagnetic three-way valve 27 only connects the piston container 24 and the electrolytic cell. An oxidation potential is applied to the working electrode 23A of the electrolytic cell, and the electric control piston mechanism 25 moves vertically upward, and the released carbon dioxide enters the piston container 24. The pressure sensor 26 monitors the internal air pressure of the piston container 24 in real time, and controls the rising rate of the electric control piston mechanism 25, so that the internal air pressure of the piston container 24 is always lower than the electrolytic cell ambient pressure by a certain level, thereby accelerating the mass transfer rate of carbon dioxide release, and thus improving the overall rate of the electrolytic cell reaction.

[0036] Stage 3 (carbon dioxide collection stage): The electromagnetic three-way valve 27 only connects the piston container 24 and the gas cylinder 29, the solenoid valve 28 at the gas cylinder opening is opened, and the electric control piston mechanism 25 moves vertically downward to inject the collected carbon dioxide into the gas cylinder 29. Stage 1 can be carried out simultaneously.

[0037] The operation of the automatic carbon dioxide capture system for waste gas thermoelectric power generation is constituted by the cross-sequential cycle operation of waste gas cooling and thermoelectric power generation for energy supply and each carbon dioxide capture unit in the above 1, 2, and 3 stages.

[0038] In summary, the carbon dioxide capture system using waste heat differential power generation provided by the present invention, compared with the capture system that recovers carbon dioxide using traditional chemical adsorbents (such as monoethanolamine), has a compact device, short pipelines, greatly limits the losses in the capture process of the released carbon dioxide, and basically achieves lossless capture. Moreover, this capture system can complete the compression and bottling of clean carbon dioxide under the condition of a compact device, forming an industrially usable product that can be directly utilized. For example, the bottled carbon dioxide can be transported to agricultural greenhouses for use, etc.

[0039] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A carbon dioxide capture system for power generation using waste heat temperature difference, characterized in that, It includes a connected thermoelectric power generation device and a carbon dioxide capture device. The carbon dioxide capture device includes a number of parallel-connected carbon dioxide capture units. Each carbon dioxide capture unit includes an electrolytic cell, a piston container, and a gas cylinder connected in sequence. The piston container includes an electronically controlled piston mechanism driven by a motor and a pressure sensor for monitoring the pressure inside the piston container. An electromagnetic three-way valve is provided between the electrolytic cell, the piston container, and the gas cylinder. The high-temperature waste gas is cooled after passing through the thermoelectric power generation device and then enters the electrolytic cell. A reduction potential is applied to the working electrode of the electrolytic cell to absorb carbon dioxide in the waste gas, and then an oxidation potential is applied to release carbon dioxide into the piston container. The carbon dioxide is injected from the piston container into the gas cylinder. The thermoelectric power generation device supplies power to the electrolytic cell.

2. The carbon dioxide capture system according to claim 1, characterized in that, The electrolytic cell includes an auxiliary electrode and an electrolyte for providing and collecting electrons for the electrochemical reaction in the capture process.

3. The carbon dioxide capture system according to claim 1, wherein The electrolytic cell includes a gas flow channel inlet pipe and a gas flow channel outlet pipe for the inlet and outlet of waste gas.

4. The carbon dioxide capture system according to claim 3, characterized in that, The gas flow channel inlet pipe is provided with an inlet pipe solenoid valve, and the gas flow channel outlet pipe is provided with an outlet pipe solenoid valve.

5. The carbon dioxide capture system according to claim 1, characterized in that, The gas cylinder includes a gas cylinder mouth solenoid valve.

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