Gas treatment apparatus

Abstract

To provide a gas treatment apparatus which efficiently separates and recovers recovered gas in treatment in a gas to be treated with less energy by a simple structure.SOLUTION: A gas treatment apparatus has: a treatment tower which stores a treatment liquid, and has a nozzle for blowing a gas to be treated into the treatment liquid provided on its lower part; a regeneration tower provided with a heating device; and a communication pipe which communicates the lower part of the treatment tower and the lower part of the regeneration tower with each other, and is inclined in such a way that it becomes lower from the treatment tower side toward the regeneration tower.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an apparatus for separating and recovering specific gas components such as carbon dioxide (hereinafter referred to as "gas to be recovered") from a gas to be treated such as exhaust gas. [Background technology]

[0002] Carbon dioxide is a greenhouse gas that causes global warming, and therefore research is being conducted into techniques for separating and recovering carbon dioxide from combustion gases, etc. Patent Document 1 discloses a carbon dioxide gas recovery device that brings a gas to be treated into contact with a lean absorbing solution capable of absorbing carbon dioxide gas in an absorption tower, causes the carbon dioxide gas in the gas to be treated to be absorbed by the lean absorbing solution to generate a rich absorbing solution, and heats the rich absorbing solution in a regeneration tower to separate and recover carbon dioxide as a gas.

[0003] In the above-mentioned device, an aqueous solution of isopropanaminoethanol or the like is used as an absorbing liquid, and when the gas to be treated is brought into contact with the absorbing liquid in the absorption tower, the carbon dioxide gas is selectively absorbed into the absorbing liquid to become a rich absorbing liquid. Next, when the rich absorbing liquid is heated in the regenerator, the carbon dioxide in the rich absorbing liquid is separated as a gas, and the separated carbon dioxide gas is recovered.

[0004] In addition, examples of treatment liquids that absorb carbon dioxide from the gas to be treated and separate it as a solid precipitate include isophorone diamine and calcium hydroxide aqueous solution. When using these treatment liquids, it is possible to separate carbon dioxide as a solid precipitate, heat and decompose this solid precipitate by batch processing, and recover the carbon dioxide gas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-131735 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology described in the above Patent Document 1, since carbon dioxide is absorbed in the lean absorbing solution, it is necessary to send all of the rich absorbing solution that has absorbed carbon dioxide to a regenerator and heat it to separate the carbon dioxide, which causes problems such as the increase in size of the absorption tower and the regenerator, and the complexity of the equipment. There is also a problem that a lot of energy is consumed to move and heat the rich absorbing solution and the lean absorbing solution.

[0007] Furthermore, when carbon dioxide is separated as a solid precipitate, it is expected that the treatment device will be smaller in size, but since the decomposition of the solid precipitate is carried out in a batch process, there is a problem in improving the efficiency of the treatment.

[0008] An object of the present disclosure is to provide a gas treatment device that has a simple structure and that separates and recovers a gas to be recovered from a gas to be treated efficiently using little energy. [Means for solving the problem]

[0009] The gas treatment device of the present disclosure comprises a treatment tower which contains a treatment liquid and has a nozzle at its lower part for injecting a gas to be treated into the treatment liquid, a regeneration tower which has a heating device, and a connecting pipe which connects the lower part of the treatment tower with the lower part of the regeneration tower and is inclined so as to become lower from the treatment tower side toward the regeneration tower side. Effect of the Invention

[0010] According to the gas treatment device of the present disclosure, a treatment liquid containing a reactive component that reacts with the recovered gas in the gas to be treated and precipitates as a solid precipitate is placed in a treatment tower and a regeneration tower, and the gas to be treated is blown into the treatment liquid from a nozzle to bring the gas to be treated into contact with the treatment liquid, whereby the recovered gas reacts with the reactive component in the treatment liquid and precipitates as a solid precipitate. The solid precipitate settles in the treatment liquid and moves by gravity through a connecting pipe to the regeneration tower. When the solid precipitate moves to the regeneration tower, it decomposes when heated by a heating device, and the recovered gas is separated and recovered as a gas. The concentration of the treatment liquid in the treatment tower and the concentration of the treatment liquid in the regeneration tower are kept in equilibrium by convection, etc. Since the solid precipitate moves to the regeneration tower by gravity, there is no need to provide a device for sending the treatment liquid from the treatment tower to the regeneration tower, and the treatment device can be made smaller, and the recovered gas can be continuously separated and recovered with high energy efficiency. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram showing a gas treatment device. [Diagram 2] FIG. 13 is a schematic diagram showing a modified example of the gas treatment device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram showing an example of a gas treatment device 1 of the present disclosure. The gas treatment device 1 has a treatment tower 10, a regenerator 20, and a communication pipe 30 that connects the treatment tower 10 and the lower part of the regenerator 20.

[0013] The treatment tower 10 is a substantially cylindrical container capable of containing the treatment liquid 18 therein, and has an exhaust hole 12 formed at the top for discharging the treated gas. The bottom wall 14 of the treatment tower 10 slopes downward as it approaches the portion where the communicating pipe 30 described below is connected.

[0014] A nozzle 16 is provided at the bottom of the treatment tower 10 for blowing the target gas such as exhaust gas into the treatment tower 10. The nozzle 16 has an injection hole configured to inject the target gas from a large number of small holes so that the target gas is blown in as fine bubbles.

[0015] The regenerator 20 is a substantially cylindrical container capable of containing the treatment liquid 26 therein, and is provided at the top with a recovery hole 22 for discharging and recovering the gas to be recovered separated from the treatment liquid. The bottom wall 24 of the regenerator 20 is formed substantially flat so as to accumulate solid precipitates moving through a communication pipe 30 (described later).

[0016] A heating device (not shown) is provided above the regeneration tower 20. The heating device is for thermally decomposing the precipitated solid matter. The heating temperature depends on the type of gas to be treated and the treatment liquid, but when carbon dioxide is precipitated as a solid matter by an aqueous solution of isophoronediamine, it is preferable to heat to about 60 degrees.

[0017] A communication pipe 30 that communicates between the inside of the treatment tower 10 and the inside of the regenerator 20 is connected to the lower part of the treatment tower 10 and the regenerator 20. The communication pipe 30 is inclined so that the regenerator 20 side is lower so that the solid precipitate that has fallen onto the bottom wall 14 of the treatment tower 10 enters the communication pipe 30 due to the inclination of the bottom wall 14 and then moves onto the bottom wall 24 of the regenerator 20 by gravity. In addition, when there is a difference in concentration between the treatment liquid 18 in the treatment tower 10 and the treatment liquid 26 in the regenerator 20, the communication pipe 30 is formed to a predetermined thickness so that the treatment liquid flows between the treatment tower 10 and the regenerator 20 by convection or the like to make the concentration uniform.

[0018] The treatment tower 10, regeneration tower 20, and communication pipe 30 are filled with treatment liquids 18, 26 for absorbing the recovered gas from the gas to be treated and separating it as a solid precipitate. When the gas to be treated is a combustion gas and the gas to be recovered is carbon dioxide, isophoronediamine or an aqueous calcium hydroxide solution can be used as the treatment liquid. The treatment liquids 18, 26 are appropriately selected and used depending on the type of recovered gas to be absorbed.

[0019] Next, an operation of the gas treatment device 1 will be described. With the treatment tower 10, the regenerator 20, and the communicating pipe 30 filled with the treatment liquid, the gas to be treated is blown into the treatment liquid 18 from the nozzle 16. Of the gas to be treated that has been blown in, the gas to be recovered reacts with and is absorbed by the treatment liquid, and precipitates as a solid deposit.

[0020] The solid precipitate settles in the treatment tower 10, and is guided by gravity along the slope of the bottom wall 14 into the communicating pipe 30, and moves to above the bottom wall 24 of the regeneration tower 20. The movement of the solid precipitate occurs by its own weight, without any external action such as a pump.

[0021] In the regenerator 20, the solid precipitate that has settled at the bottom is heated by a heating device (not shown). When the heating device heats the upper part of the treatment liquid 26 in the regenerator 20, the treatment liquid 26 flows, and the heated treatment liquid 26 heats and lifts up the solid precipitate on the bottom wall 24 of the regenerator 20. The heated solid precipitate decomposes, and the gas to be recovered is collected as a gas at the top of the regenerator 20 and recovered from the recovery hole 22.

[0022] As the treatment progresses, the concentration of the treatment liquid 18 in the treatment tower 10 decreases and the concentration of the treatment liquid 26 in the regenerator 20 increases, but because the treatment liquid 18 in the treatment tower 10 is flowing due to the injection of the target gas and the treatment liquid 26 in the regenerator 20 is flowing due to heating, the overall concentration is kept approximately uniform. Therefore, the target gas can be continuously injected and the recovered gas can be continuously recovered.

[0023] 2 shows a modified example of the gas treatment device 1'. The same components are given the same reference numerals, and detailed explanations are omitted. In this example, a baffle plate 28 is formed at the top of the connection part between the inner surface of the regenerator 20 and the communicating pipe 30, protruding into the regenerator 20. Since the solid precipitates that precipitate in the treatment tower 10 are very small particles, the flow of the treatment liquid 26 in the regenerator 20 may agitate and push back the solid precipitates in the communicating pipe 30, but the provision of the baffle plate 28 can prevent the solid precipitates from being agitated.

[0024] The gas treatment device of the present disclosure is not limited in any way to the gas to be treated or the recovered gas to be separated, so long as it can separate the recovered gas as a solid precipitate using a treatment liquid, in addition to separating carbon dioxide from exhaust gas. [Industrial Applicability]

[0025] This is suitably applicable to cases where a gas to be recovered is separated from a gas to be treated and recovered. [Explanation of symbols]

[0026] 10 Processing Tower 12 Discharge hole 14 Bottom wall 16 Nozzles 18 Processing fluid 20 Regeneration Tower 22 Recovery Hole 24 Bottom wall 26 Processing fluid 28 Rectifier plate 30 Communication pipe

Claims

1. a treatment tower containing a treatment liquid and having a nozzle at its lower part for blowing the gas to be treated into the treatment liquid; a regeneration tower provided with a heating device; a communication pipe that communicates the lower part of the treatment tower with the lower part of the regeneration tower and is inclined so as to become lower from the treatment tower side toward the regeneration tower side; A gas treatment device comprising:

2. The bottom wall of the treatment tower is inclined so as to become lower toward the connection portion with the communicating pipe. The gas treatment device of claim 1 .

3. a discharge hole for discharging the treated gas is formed at the top of the treatment tower; A recovery hole for recovering the gas to be recovered is formed at the top of the regeneration tower. The gas treatment device of claim 1 .

4. A straightening plate protruding into the regeneration tower is provided on the inner surface of the regeneration tower and above the connection portion between the communication pipe and the regeneration tower. The gas treatment device according to any one of claims 1 to 3.

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