JPH08337545A - Separating and recovering device of carbon dioxide - Google Patents

Abstract

PURPOSE: To provide the subject device constituted by an absorption tower separating and recovering CO2 , a regeneration tower separating CO2 from an absorbing liquid and a reaction tower synthesizing methanol from CO2 , capable of separating and recovering CO2 from an exhaust gas with a good efficiency, and effectively reusing CO2 . CONSTITUTION: In the separating and recovering device of carbon dioxide, firstly an exhaust gas containing CO2 is fed to an absorption tower 14 to separate and recover CO2 in the exhaust gas with an absorbing liquid, then CO2 is separated from the absorbing liquid in a regenerating tower 18 connected to the absorption tower 14 by e.g. a method of heating the CO2 absorbing liquid and then the CO2 is reacted with hydrogen in a reaction tower 20 connected to the regeneration tower 18 to synthesize methanol. In the absorption tower 14, by constituting so as to spray the absorbing liquid from a spraying device to make the large contact area with the exhaust gas and CO2 , the separation and recovery rate is preferably increased. Also, the structure of the spraying device, when having two spraying holes directed upward slantly, preferably facilitates the spraying of the absorbing liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon dioxide separation / collection apparatus for reacting carbon dioxide separated and collected from exhaust gas with hydrogen to synthesize methanol.

[0002]

2. Description of the Related Art As a carbon dioxide separating and recovering apparatus for separating and recovering carbon dioxide from an exhaust gas containing carbon dioxide, a so-called wet wall type carbon dioxide absorption tower is known. In this wet wall type absorption tower,
The carbon dioxide in the exhaust gas is separated and recovered by flowing an absorption liquid of carbon dioxide on the inner surface of the tube and bringing it into contact with the exhaust gas passing through the tube.

[0003]

However, in the conventional carbon dioxide separation / collection device, it is difficult to increase the separation / collection efficiency of carbon dioxide because the contact area between the exhaust gas containing carbon dioxide and the absorbing liquid is small. It was Moreover, even if carbon dioxide is recovered from exhaust gas such as combustion gas,
Since the technology for recycling carbon dioxide has not been completed, it is considered that carbon dioxide should be discarded at the seabed or oilfield mining traces, or released into the atmosphere.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to efficiently separate and recover carbon dioxide from exhaust gas containing carbon dioxide and to reuse carbon dioxide.

[0005]

A carbon dioxide separation and recovery apparatus according to the present invention is connected to an absorption tower to which an exhaust gas containing carbon dioxide is supplied and which separates and recovers carbon dioxide in the exhaust gas with an absorption liquid, and to the absorption tower. It is composed of a regeneration tower that separates carbon dioxide from the absorbed liquid that has absorbed carbon dioxide, and a reaction tower that is connected to the regeneration tower and reacts the separated carbon dioxide with hydrogen to synthesize methanol. A technology is applied in which the absorption tower is provided with a sprayer for spraying the absorption liquid, and two injection holes for ejecting the absorption liquid are formed obliquely upward so that their extension lines intersect.

[0006]

When the exhaust gas containing carbon dioxide is sent to the absorption tower, the absorbing liquid in the absorption tower absorbs carbon dioxide in the exhaust gas. By sending the absorption liquid that has absorbed carbon dioxide to the regeneration tower, carbon dioxide is separated from the absorption liquid, and the separated carbon dioxide is sent to the reaction tower. Then, carbon dioxide is reacted with hydrogen in the reaction tower to synthesize and collect methanol. In the atomizer of the absorption tower, by spraying the absorbing liquid, the atomized absorbing liquid comes into contact with the exhaust gas to enhance the carbon dioxide absorbability. In the nebulizer, the absorbing liquid is easily atomized by ejecting the absorbing liquid from the two ejection holes and causing the absorbing liquid to collide with each other.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the carbon dioxide separating and collecting apparatus according to the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1 is a carbon dioxide separation / collection device, 11 is a carbon dioxide gas generation source, 12 is a combustion gas generation source, 13 is a heat exchanger, 14 is an absorption tower, 15 is an off-gas treatment system, and 16 is a diffuser. Vessel, 17 is a heat exchanger, 18 is a regeneration tower, 19 is a power source, 2
Reference numeral 0 is a reaction tower, 21 is a hydrogen gas supply source, and 22 is a methanol storage tank.

The carbon dioxide gas generation source 11 is, for example, one that generates carbon dioxide near room temperature or one that stores carbon dioxide, and the combustion gas generation source 12 has a relatively high temperature in a thermal power plant or the like. It produces exhaust gas. These gas generation sources 11 and 12 are connected to the absorption tower 14 directly or via a heat exchanger 13.

The absorption tower 14 is designed to bring carbon dioxide in exhaust gas into contact with an absorption liquid for separation and recovery. As the absorption liquid, for example, for exhaust gas near room temperature, 2
About 0% amine-based aqueous solution, and potassium carbonate-based aqueous solution is applied to exhaust gas near 100 ° C.

The internal structure of the absorption tower 14 will be described with reference to FIG. The absorption tower 14 includes, for example, an absorption liquid inlet 31 arranged at an upper portion, a plurality of sprayers 32 arranged in the tower at intervals in the vertical direction, and a connection state arranged between the inlet 31 and the sprayer 32. Pipe 33, an exhaust gas inlet 34 connected to the carbon dioxide generation source 11 and the heat exchanger 13 at a lower position, a gas outlet 35 arranged at an upper position for discharging off gas, and a bottom portion. An absorption liquid discharge port 36 for extracting the absorption liquid that has been disposed and has absorbed carbon dioxide is provided respectively.

Details of the sprayer 32 will be described with reference to FIG. The sprayer 32 has a support step portion 41 provided on the inner wall surface of the container of the absorption tower 14 and a horizontal plate 42 placed on the support step portion 41. The horizontal plate 42 is connected to the pipe 33. Two injection holes 43, which are connected to each other and inject the absorbing liquid, are opened obliquely upward so that their extension lines intersect. The absorbing liquid jetted from the two jetting holes 43 facing each other becomes a mist by colliding inside the container of the absorption tower 14.

The off-gas treatment system 15 is connected to the gas discharge port 35 of the absorption tower 14, and performs final treatment on the exhaust gas which has been subjected to decarbonization treatment, if necessary, and the diffuser 1
The off gas (exhaust gas) from 6 is diffused into the atmosphere.

The heat exchanger 17 is arranged between the absorption tower 14 and the regeneration tower 18 so as to preheat the carbon dioxide absorbing liquid supplied to the regeneration tower 18, and the primary system is regenerated. The secondary system is connected to the vicinity of the inner bottom of the tower 18 and the inlet 31 of the absorption tower 14, and the secondary system is connected to the absorbent discharge port 36 of the absorption tower 14 and the upper part of the regeneration tower 18 to form a primary system and a secondary system. Heat is exchanged between the heat mediums (absorption liquids) of the system.

The regeneration tower 18 is connected not only to the absorption tower 14 but also to the power supply 19 and the reaction tower 20. By heating the carbon dioxide absorbent, the carbon dioxide in the absorbent is removed. The heater 19a, which separates in a gas state and emits heat, is built into the heater 19a which generates heat when fed from the power supply 19.

The reaction tower 20 is connected to the regeneration tower 18, the hydrogen gas supply source 21 and the methanol storage tank 22, and is a catalyst (such as CuO) for synthesizing methanol by reacting carbon dioxide with hydrogen. The one with built-in is applied. The hydrogen gas supply source 21 supplies hydrogen gas to the reaction tower 20. As the hydrogen gas supply source 21, for example, surplus of nuclear power generation when the power consumption is low, such as at night. Those that generate hydrogen gas by electrolysis of water using electric power are applied. On the other hand, the methanol storage tank 22 stores the synthesized methanol.

In the carbon dioxide separation / recovery apparatus 1 configured as described above, one or both of the carbon dioxide gas generation source 11 and the combustion gas generation source 12 are operated to generate carbon dioxide or exhaust gas containing the carbon dioxide. Absorption tower 1
4, the absorption liquid is atomized in the absorption tower 14 by the operation of the atomizer 32, and the exhaust gas introduction port 3
When the exhaust gas introduced into the absorption tower 14 from 4 and the mist-like absorption liquid come into contact with each other, carbon dioxide is taken into the absorption liquid, and the off gas from which the carbon dioxide is removed is the gas discharge port 3
5 is discharged and treated by the off-gas treatment system 15,
In addition, the absorption liquid that has absorbed carbon dioxide is the absorption liquid discharge port 3
It is discharged from 6 and sent to the next stage. At this time, if the temperature of the gas supplied from the carbon dioxide gas generation source 11 or the combustion gas generation source 12 is outside the above-mentioned room temperature to 100 ° C., cooling (or heating) by the operation of the heat exchanger 13 is performed. ) To set a desired temperature.

The absorption liquid which has absorbed the carbon dioxide and is sent from the absorption tower 14 is heated by passing through the heat exchanger 17, and is sent to the regeneration tower 18 in a state where the temperature is raised. The inside of the regeneration tower 18 is maintained at a high temperature heated by the power supply 19 and promotes separation of carbon dioxide from the absorbing liquid. After that, the absorbing liquid that has released the carbon dioxide gas is returned to the absorption tower 14 again, and the carbon dioxide is sent to the reaction tower 20. In addition,
In the absorbing liquid returned from the regeneration tower 18, the heat exchanger 1
Due to the heat exchange in 7, heat energy is transferred to the carbon dioxide absorbent.

In the reaction tower 20, carbon dioxide and hydrogen supplied from the hydrogen gas supply source 21 are reacted with each other by using a catalyst such as copper oxide to synthesize methanol. The synthesized methanol is sent to and stored in the methanol storage tank 22.

To capture the explanation, in the atomizer 32 in the absorption tower 14, since the absorbing liquid is atomized from the injection hole 43, the contact area between the exhaust gas and the absorbing liquid becomes large, and the carbon dioxide from the exhaust gas becomes large. Separation and recovery of is efficiently performed. Further, the horizontal plate 42 is replaced when corrosion occurs due to the absorbing liquid.

[0020]

The carbon dioxide separation and recovery system according to the present invention has the following effects. (1) Carbon dioxide is separated and recovered from exhaust gas containing carbon dioxide, carbon dioxide is separated from the absorption liquid, and then methanol is synthesized, so that carbon dioxide can be effectively reused without emission to the atmosphere or disposal. be able to. (2) The efficiency of separating and collecting carbon dioxide from the exhaust gas can be increased by spraying the absorbing liquid in a mist form by the atomizer in the absorption tower to increase the contact area between the exhaust gas and the absorbing liquid. (3) By applying a structure in which the two injection holes are arranged obliquely upward as the atomizer, atomization of the absorbing liquid can be promoted and the recovery efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of a carbon dioxide separation and recovery apparatus according to the present invention.

FIG. 2 is a front sectional view of an absorption tower portion in FIG.

3 is a front sectional view showing the structure of the sprayer in FIG. 2. FIG.

[Explanation of symbols]

 1 Carbon Dioxide Separation and Recovery Device 11 Carbon Dioxide Gas Source 12 Combustion Gas Source 13 Heat Exchanger 14 Absorption Tower 15 Offgas Treatment System 16 Dissipator 17 Heat Exchanger 18 Regeneration Tower 19 Power Supply 19a Heater 20 Reaction Tower 21 Hydrogen Gas Supply Source 22 Methanol storage tank 31 Absorbing liquid inlet 32 Sprayer 33 Piping 34 Exhaust gas inlet 35 Gas outlet 36 Absorbing liquid outlet 41 Supporting step 42 Horizontal plate 43 Injection hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sachiko Fujimoto 1st Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishi Kawashima Harima Heavy Industries, Ltd. Yokohama Engineering Center

Claims (3)

[Claims] 1. An absorption tower (14) which is supplied with an exhaust gas containing carbon dioxide and separates and recovers carbon dioxide in the exhaust gas by an absorption liquid, and carbon dioxide from an absorption liquid which is connected to the absorption tower and has absorbed carbon dioxide. A carbon dioxide separation and recovery device comprising a regeneration tower (18) for separation and a reaction tower (20) connected to the regeneration tower for reacting the separated carbon dioxide with hydrogen to synthesize methanol. 2. The carbon dioxide separation and recovery device according to claim 1, wherein the absorption tower (14) comprises a sprayer (32) for spraying an absorbing liquid for absorbing carbon dioxide in a mist state. 3. Two injection holes (43) for injecting the absorbing liquid
3. The carbon dioxide separation and recovery device according to claim 2, wherein the carbon dioxide separation recovery device is formed obliquely upward so that the respective extension lines intersect.