Exhaust gas pretreatment facility, exhaust gas treatment facility, and co2 separation / recovery method for exhaust gas pretreatment facility

Abstract

This exhaust gas pretreatment facility is disposed on the entrance side of a CO2 separation / recovery facility for separating and recovering CO2 from combustion exhaust gas. By comprising a layered double hydroxide (LDH) reaction tower filled with LDH and a gas cooling tower that cools the combustion exhaust gas discharged from the LDH reaction tower with cooling water, the removal of acidic gas components contained in the exhaust gas is efficiently performed with low equipment costs and operating costs during the separation and recovery of CO2 from the exhaust gases emitted by waste incinerators and coal-fired power plants.

Description

Exhaust gas pretreatment equipment, exhaust gas treatment equipment, and CO2 separation and capture method for exhaust gas pretreatment equipment

[0001] The present invention relates to an exhaust gas pretreatment facility, an exhaust gas treatment facility, and a method for separating and capturing CO2 in the exhaust gas pretreatment facility. In particular, the present invention relates to an exhaust gas pretreatment facility that is suitable for use in waste incineration facilities including garbage and coal-fired power plants, and that is capable of removing or reducing acid gases in the exhaust gas to a predetermined concentration when separating and capturing carbon dioxide CO2 contained in the combustion exhaust gas, an exhaust gas treatment facility equipped with the exhaust gas pretreatment facility, and a method for separating and capturing CO2 in the exhaust gas pretreatment facility.

[0002] In the operation of waste incineration facilities and coal-fired power plants, which burn waste, including garbage, and recover the waste heat to generate electricity, the exhaust gases ultimately emitted from the chimney contain a considerable amount of CO2. In recent years, preventing global warming has become increasingly important, and reducing CO2 emissions has become an urgent issue.

[0003] There are currently several facilities in Japan that capture CO2 from flue gas at waste incineration facilities, and these capture methods include chemical absorption, in which CO2 is separated from the flue gas using an aqueous solution of an amine that has the property of absorbing CO2, and then the amine solution that has absorbed the CO2 is heated to desorb the CO2 from the amine solution and capture it, and physical adsorption, in which CO2 is held under a predetermined high pressure to be adsorbed by an adsorbent that has the property of adsorbing CO2, and then the pressure is reduced to desorb the CO2 from the adsorbent and capture it. Both the chemical absorption and physical adsorption methods are intended for flue gas at 40 to 60°C, so flue gas at 100°C or higher must be cooled in advance in a gas cooling tower, for example by directly contacting it with water.

[0004] It is known that the absorption or adsorption of CO2 by the amine aqueous solution used in the chemical absorption method and the adsorbent used in the physical adsorption method is hindered by the influence of acidic gases such as sulfur dioxide (SO2) that are also contained in flue gas. In particular, SO2 has a higher affinity with amine aqueous solutions or adsorbents than CO2. Taking the chemical absorption method as an example, the amine aqueous solution that has absorbed CO2 must be heated at a higher temperature than CO2 to desorb SO2. Therefore, if the temperature of the amine aqueous solution is not raised to the SO2 desorption temperature for economic reasons, the amine aqueous solution will always retain SO2, resulting in a reduced CO2 absorption capacity, which is undesirable. Furthermore, hydrogen chloride (HCl), which is also contained as an acidic gas, is also likely to have adverse effects such as equipment corrosion, and its introduction into a CO2 separation and capture facility is also undesirable. Furthermore, when an amine aqueous solution that has absorbed acidic gases such as SO2 is heated at the CO2 desorption temperature, a small amount of SO2 is desorbed. This means that the captured CO2 will contain these acidic gas components as impurities, and when the captured CO2 is reused as a raw material in the production of other products, there is a concern that this may affect the manufacturing process, such as reducing the quality of the CO2 recycled product or poisoning or deteriorating the catalyst, which is also undesirable.

[0005] Therefore, equipment is required to remove or reduce the acid gases in the flue gas to a predetermined concentration. Methods for removing acid gases include dry treatment, in which an alkaline dechlorinating agent such as slaked lime is sprayed upstream of the dust collector, and wet treatment, in which an alkaline aqueous solution such as a caustic soda solution is passed countercurrently against the flue gas. The acid gas components in the flue gas introduced into CO2 separation and capture facilities, such as chemical absorption systems, are often required to be less than 3 ppm, and therefore wet treatment, which has excellent acid gas removal capabilities, is adopted. However, wet treatment generates a large amount of wastewater after flue gas treatment. This increases the size of the equipment required for wastewater treatment and requires a destination for the wastewater to be discharged, which increases costs and is undesirable.

[0006] Furthermore, Patent Document 1 discloses a method of employing a dry process to remove acid gases from exhaust gases. In this case, a large amount of demineralizing agent must be injected to reduce the acid gas concentration, which increases costs and generates a large amount of demineralized residue that must be disposed of in a landfill, undesirably reducing the remaining life of the landfill.

[0007] Furthermore, when reducing the temperature of exhaust gas in a gas cooling tower, methods have been disclosed for reducing the amount of condensed water by using indirect air cooling or mixing room-temperature air to prevent the condensation of moisture contained in the exhaust gas. However, these methods increase the amount of exhaust gas introduced into the CO2 separation and capture equipment, expanding the scale of the equipment and increasing installation costs and space, which is undesirable. In addition, the CO2 concentration in the exhaust gas decreases, reducing the CO2 capture efficiency in the CO2 separation and capture process, which also leads to an undesirable increase in equipment size.

[0008] Japanese Patent Application Laid-Open No. 2023-17514

[0009] Layered double hydroxide (LDH) is a material capable of reducing the HCl and sulfur dioxide (SOx) contained in incineration flue gas to the low levels required by CO2 capture equipment. LDH is composed of magnesium (Mg), aluminum (Al), and hydroxide (OH), and is composed of layers of positively charged crystals. Negatively charged ions and interlayer water exist between the layers. Typically, these negative ions are most stable in the form of carbonate ions, and carbonate-type LDHs exist in nature. When carbonate-type LDH is brought into contact with flue gas containing acidic gases, in the case of HCl, a reaction occurs in which the carbonate ions between the LDH layers exchange with the chloride ions in the HCl, enabling the removal of acidic gases. Taking advantage of this property, by passing flue gas through a layer packed with an appropriate amount of LDH, acidic gas removal efficiency equivalent to or better than that achieved by wet treatment can be achieved.

[0010] For example, in the case of a waste incineration facility, the acid gas concentration in combustion exhaust gas is 200 to 300 ppm HCl before removal treatment. Dry treatment is commonly used in typical waste incineration facilities, where acid gases are removed by injecting an alkaline dechlorinating agent such as slaked lime upstream of the dust collector and depositing it on a filter cloth inside the dust collector. Slaked lime or the like is typically injected to reduce the HCl concentration in the exhaust gas at the dust collector outlet after removal to 50 ppm or less. When introducing a portion or all of this exhaust gas into a CO2 capture / separation system, acid gases must be removed to less than 3 ppm. Here, LDHs, which have acid gas removal capabilities equivalent to or greater than those of wet treatment methods, can be applied. Simply passing the acid gas-containing exhaust gas through a packed bed containing these LDHs can reduce the acid gas concentration to the level required by the CO2 capture / separation system without generating wastewater, completing the acid gas removal process as a pretreatment for CO2 capture / separation. In this case, by installing a gas cooling tower downstream of the LDH reactor containing the LDH packed bed, the condensed water generated contains almost no acidic gas components, and therefore the pH of the condensed water is hardly lowered by the acidic gas components, and the amount of alkaline aqueous solution such as caustic soda solution added to adjust the pH before discharge can be reduced, thereby reducing the amount of wastewater.

[0011] Furthermore, since there is no need to add air to cool the gas, it is possible to send the gas to the CO2 separation and capture equipment without increasing the amount of exhaust gas. This is advantageous because it does not increase the size of the CO2 separation and capture equipment, and does not increase the equipment or installation space. Since it does not increase the installation space, it is advantageous for retrofitting to existing waste incineration facilities that have little free space, for example.

[0012] The present invention has been made in consideration of the above circumstances, and its first objective is to provide an exhaust gas pretreatment facility that can efficiently remove acid gas components contained in exhaust gases at low equipment and operating costs when CO2 separation and capture equipment is installed in waste incineration facilities, coal-fired power plants, etc.

[0013] A second object of the present invention is to provide an exhaust gas pretreatment facility that allows CO2 separation and capture equipment to be easily added to existing waste incineration facilities, coal-fired power plants, and the like.

[0014] A third object of the present invention is to provide an exhaust gas treatment facility in which a CO2 separation and capture facility is installed in a main line extending from an incinerator or boiler to a chimney.

[0015] A fourth object of the present invention is to provide a method for separating and recovering CO2 in an exhaust gas pretreatment facility that is suitable for use in the regeneration or replacement of LDH.

[0016] The present invention solves the first problem by providing an exhaust gas pretreatment facility that is placed on the inlet side of a CO2 separation and capture device that separates and captures CO2 from combustion exhaust gas, and that is characterized by comprising an LDH reaction tower filled with layered double hydroxide LDH, and a gas cooling tower that cools the combustion exhaust gas discharged from the LDH reaction tower with cooling water.

[0017] Here, the LDH can be made into granules having a diameter of, for example, 0.5 to 4 mm, preferably 1.0 to 2.5 mm, to enhance the breathability.

[0018] Furthermore, the LDH reaction tower is filled with the LDH so that the LDH moves from top to bottom, and the LDH that has completed adsorption can be regenerated and supplied from the top of the LDH reaction tower, thereby enabling the LDH to be recycled.

[0019] The LDH reactor may be provided with an LDH supply facility at its upper portion for replenishing LDH capable of removing acidic gases, an LDH extractor at its lower portion for extracting LDH that has completed adsorption of acidic gases, and an LDH discharge facility for discharging the extracted LDH.

[0020] Furthermore, the amount of LDH discharged from the LDH discharger can be controlled in accordance with the pH of the condensed water in the condensed water tank of the gas cooling tower or the amount of pH adjuster supplied to the condensed water tank.

[0021] In addition, a regeneration tank for carrying out the regeneration is provided below the LDH reaction tower, making it possible to reduce the size of the equipment.

[0022] Furthermore, the second problem is solved by providing the exhaust gas pretreatment equipment in a bypass line of a main line leading from an incinerator or a boiler to a chimney.

[0023] Furthermore, by providing the exhaust gas pretreatment equipment in the middle of the main line leading from the incinerator or boiler to the chimney, the third problem is solved, and a bypass line is no longer necessary.

[0024] The present invention also solves the fourth problem by monitoring the pH value of the cooling water in the gas cooling tower in the CO2 separation and capture method using the exhaust gas pretreatment equipment, and regenerating or replacing the LDH when the pH value falls below a predetermined value.

[0025] Alternatively, in the CO2 separation and recovery method using the exhaust gas pretreatment equipment, the amount of pH adjuster added, which is determined from the pH value of the cooling water in the gas cooling tower, is monitored, and when the amount exceeds a predetermined value, the LDH is regenerated or replaced, thereby solving the above-mentioned problem.

[0026] According to the present invention, it is possible to efficiently remove HCl gas, which corrodes the inside of a CO2 separation and capture facility, and gases such as SO2, which bind more selectively to adsorbents than CO2, without using wet treatment methods, etc. Furthermore, it is possible to maintain the pH of the exhaust gas condensate discharged from the gas cooling tower installed downstream of the LDH reactor at a near neutral level, which makes it possible to reduce the amount of pH adjuster, such as a caustic soda solution, that has been conventionally used, added, thereby further reducing equipment costs and operating costs.

[0027] FIG. 1 is a diagram showing the overall configuration of a first embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view showing the main configuration of the first embodiment; FIG. 3 is a cross-sectional view showing the operation in an LDH reaction column; FIG. 4 is a diagram showing the overall configuration of a second embodiment of the present invention; and FIG. 5 is a diagram showing the overall configuration of a third embodiment of the present invention.

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the contents described in the following embodiments and examples. Furthermore, the constituent elements in the embodiments and examples described below include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the constituent elements disclosed in the embodiments and examples described below may be appropriately combined or appropriately selected for use.

[0029] First, an exhaust gas treatment system to which the present invention is applied will be described.

[0030] As shown in FIG. 1 , this exhaust gas treatment system has a main line 10 (shown by a thick solid line) through which exhaust gas flows from an incinerator or boiler 12 to a chimney 18 via a dust collector 14, a denitration reaction tower (not shown), an induced draft fan 16, etc., and is discharged into the atmosphere.

[0031] In the first embodiment of the present invention, in the flue gas treatment system described above, a bypass line 20 (shown by a thick dashed line) is provided between the dust collector 14, to which a dechlorinating agent such as slaked lime has been sprayed, and the flue downstream of the induced draft fan 16, and the chimney 18, and some or all of the flue gas is sucked into the bypass line 20 by a suction fan 70. The bypass line 20 is provided with the flue gas pretreatment equipment 30 according to the present invention, the suction fan 70, and a known CO2 separation and capture equipment 80, and the CO2 separation and capture equipment 80 is provided with a flue 82 for capturing the separated and captured CO2, and a flue 84 for returning the flue gas after CO2 removal to the main line 10.

[0032] The flue gas pretreatment facility 30 mainly includes an LDH reactor 32 according to the present invention and a gas cooling tower 50. The flue gas drawn into the flue gas pretreatment facility 30 is first passed through the LDH reactor 32.

[0033] 2 in detail, the LDH reaction tower 32 is provided with an inlet 32A for an exhaust gas containing an acidic gas and an outlet 32B for an exhaust gas after the acidic gas has been removed, and the exhaust gas to be introduced into the LDH reaction tower 32 is introduced from the exhaust gas inlet 32A at the bottom of the LDH reaction tower 32, and the exhaust gas after the acidic gas has been removed is discharged from the exhaust gas outlet 32B at the top of the LDH reaction tower 32. Note that the efficiency of acidic gas removal is not affected whether the exhaust gas is introduced from the top or discharged from the bottom, and either method is acceptable.

[0034] Inside the LDH reaction tower 32, LDH particles 33 having a predetermined particle diameter, for example, 0.5 to 4 mm, preferably 1.0 to 2.5 mm, are filled in a predetermined amount, for example, at a space velocity SV (=gas flow rate / filled volume: unit h -1 )=(1,000~10,000h -1 , preferably 1,500 to 3,000 h -1 ) range. Here, if the space velocity SV is small, the LDH packing amount relative to the gas flow rate increases, and acid gases can be removed for a longer period of time with a single packing. On the other hand, increasing the LDH packing amount results in an increase in the size of the acid gas treatment equipment, which is undesirable from the viewpoints of minimizing equipment costs and installation area. In order to reduce equipment costs, it is desirable to increase the space velocity SV and reduce the LDH packing amount (packing volume). Therefore, a space velocity SV of 1,000 to 10,000 h -1 , preferably 1,500 to 3,000 h -1 Acid gas treatment equipment designed to be in the range of this range is optimal for ensuring treatment time while minimizing equipment costs and installation area.

[0035] Furthermore, as the particle size of the LDH particles 33 decreases, the gaps during packing become smaller, increasing the differential pressure between the inlet gas and the outlet gas of the LDH reaction tower 32, which is undesirable as it increases the power consumption of the suction fan 70. However, the specific surface area of ​​the LDH material increases, which is a desirable result in improving the efficiency of acid gas removal. In the example, when the particle size of the LDH was 3.0 mm, the differential pressure between the inlet and outlet gas of the LDH reaction tower 32 was 0.4 to 0.5 kPa. A differential pressure of up to about 1.0 kPa is at a level that does not pose a problem in terms of the power consumption of the suction fan 70, so an LDH particle size of 1.0 mm to 2.5 mm is desirable.

[0036] The LDH reactor 32 is provided at its upper portion with an LDH supplying facility 36 for replenishing LDH capable of removing acidic gases, and at its lower portion with an LDH discharging facility 38 for discharging LDH that has completed adsorption of acidic gases.

[0037] An example of the movement of the LDH particles 33 in the LDH reaction tower 32 is shown in Fig. 3. The LDH particles 33 supplied from above to the LDH reaction tower 32 move downward within the LDH reaction tower 32 while being cut out by an LDH cutter 35 provided below. During this process, the LDH particles react with the exhaust gas supplied from below, and purified gas is discharged from above.

[0038] As will be described later, the amount of LDH discharged from the LDH discharger 35 of the LDH discharge facility 38 can be controlled, for example, according to the pH in the condensed water tank 56 of the gas cooling tower 50 or the amount of pH adjuster (e.g., an alkaline aqueous solution such as a caustic soda solution) supplied to the condensed water tank 56.

[0039] The LDH discharged from the LDH discharge facility 38 is introduced into a regeneration tank 40 to which an alkaline aqueous solution, for example, a caustic soda solution, is supplied, where it is regenerated, dried through a dryer 42, and then supplied to the LDH supply facility 36 for recycling. This allows the amount of expensive LDH used to be reduced.

[0040] Next, as shown in FIG. 2, the exhaust gas from which acid gases have been removed after passing through the LDH reaction tower 32 is introduced into a gas inlet 50A at the bottom of a gas cooling tower 50 installed downstream of the LDH reaction tower 32.

[0041] The gas cooling tower 50 has a filler packed bed 53 filled with filler 52 for heat exchange inside, and cooling water flows down from a cooling water distribution plate 54 installed above it and is collected in a condensed water tank 56.

[0042] For example, a metal, preferably a stainless steel, pall ring can be used as the packing material 52. Since the amount of acid gas is reduced by the LDH reactor 32 provided in the upstream stage, expensive materials such as SUS316 or 316L are not necessary, and the cheaper SUS304 is sufficient. It is desirable to use a pall ring with a small diameter so that the differential pressure does not exceed a predetermined value.

[0043] The condensed water collected in the condensed water tank 56 is cooled by indirect cooling water via an indirect heat exchanger 64 by a pump 62 of a cooling water supply facility 60, for example, and is then supplied as direct cooling water to the upper part of the gas cooling tower 50. In the gas cooling tower 50, if the cooling water is continuously brought into direct contact with the high-temperature exhaust gas, the temperature of the direct cooling water rises and the cooling efficiency decreases, so to prevent this, the direct cooling water is cooled by the indirect heat exchanger 64.

[0044] In the gas cooling tower 50, as shown in FIG. 2, cooling water is sprayed to cool the exhaust gas at a temperature of 100°C or higher, for example, about 160°C, to about 40 to 60°C. The cooling water comes into direct contact with the exhaust gas to cool the temperature of the exhaust gas, and the condensed water generated by condensation of the moisture in the exhaust gas is collected in a condensed water tank 56 that can be held for a short period of time.

[0045] If acidic gases are sufficiently removed in the LDH reactor 32, the pH of the condensed water will be near neutral. However, as the acidic gas adsorption capacity of the LDH granules 33 decreases and the amount of acidic gas introduced into the gas cooling tower 50 increases, the pH of the condensed water will decrease toward the acidic side. This phenomenon can be utilized to monitor the pH of the condensed water using a pH meter 66 and manage the timing of regeneration or replacement of the LDH granules 33. Alternatively, the timing of regeneration or replacement of the LDH granules 33 can be managed by monitoring and managing the amount of an alkaline aqueous solution, such as a caustic soda solution, added as a pH adjuster when the pH shifts toward the acidic side. If the gas cooling tower 50 is installed upstream of the LDH reactor 32, the exhaust gas containing acidic gases is cooled by direct contact with the cooling water, and the acidic components migrate to the condensed water, causing the pH to decrease toward the acidic side. This increases the amount of alkaline aqueous solution, such as a caustic soda solution, used for neutralization treatment, which increases costs and the amount of condensed water, making this undesirable.

[0046] The exhaust gas cooled to a predetermined temperature, for example, about 40 to 60°C, in the gas cooling tower 50 is supplied from a gas outlet 50B provided at the top of the gas cooling tower 50 through a suction fan 70 to a CO2 separation and capture facility 80. The CO2 captured in the CO2 separation and capture facility 80 is discharged through a flue 82, and the remaining exhaust gas is returned to the chimney 18 of the main line 10 through a flue 84.

[0047] Next, a second embodiment of the present invention is shown in Fig. 4. In this second embodiment, in the exhaust gas pretreatment equipment 30 provided in the bypass line 20 similar to that of the first embodiment, a regeneration tank 40 is provided immediately below the LDH reaction tower 32, thereby reducing the size of the equipment.

[0048] In this embodiment, the LDH granules 33 regenerated in the regeneration tank 40 are discharged from the LDH reaction tower 32 by the LDH discharge equipment 38, dried in a dryer 42, and then supplied to the LDH supply equipment 36 for circulating use.

[0049] The other configurations and operations are the same as those of the first embodiment, so the explanation will be omitted.

[0050] Next, a third embodiment of the present invention is shown in FIG. 5, in which an LDH reactor 32 and a gas cooling tower 50 are provided in the main line 10 instead of the bypass line 20.

[0051] The other configurations and operations are the same as those of the first embodiment, so the explanation will be omitted.

[0052] According to this embodiment, the present invention can be implemented without providing the bypass line 20 .

[0053] In the above-described embodiments, since the regeneration tank 40 and the dryer 42 are provided, the LDH granules 33 can be regenerated and recycled, which is highly economical. It is also possible to omit the regeneration tank 40 and the dryer 42 and use up the LDH granules 33.

[0054] In the above embodiment, the LDH packed into the LDH reaction tower 32 is LDH granules 33, and a moving bed is formed in the LDH reaction tower 32. However, it is not always necessary to use LDH granules 33, and it is not necessary for a moving bed to be formed in the LDH reaction tower 32.

[0055] Furthermore, the configuration of the gas cooling tower 50 is not limited to one that uses the indirect heat exchanger 64 .

[0056] The temperature of the exhaust gas at each location is just one example.

[0057] In the above explanation, the present invention is applied to pretreatment for CO2 separation and recovery of exhaust gas from waste incineration facilities such as municipal waste, but the application of the present invention is not limited to this and can also be applied to pretreatment for CO2 separation and recovery of exhaust gas from, for example, coal-fired power plants.

[0058] When separating and recovering carbon dioxide CO2 contained in combustion exhaust gas at waste incineration facilities including garbage and lime-fired power plants, an exhaust gas pretreatment facility can be provided that can efficiently remove acid gases from the exhaust gas at low equipment and operating costs.

[0059] DESCRIPTION OF SYMBOLS 10...Main line 12...Incinerator / boiler 14...Dust collector 16...Induced draft fan 18...Chimney 20...Bypass line 30...Exhaust gas pretreatment equipment 32...LDH reaction tower 33...LDH granules 34...LDH packed bed 36...LDH supply equipment 38...LDH discharge equipment 40...Regeneration tank 42...Dryer 50...Gas cooling tower 52...Filler 53...Filler packed bed 54...Cooling water distribution plate 56...Condensed water tank 60...Cooling water supply equipment 64...Indirect heat exchanger 66...pH meter 70...Suction fan 80...CO2 separation and recovery equipment

Claims

1. An exhaust gas pretreatment facility that is disposed on the inlet side of a CO2 separation and capture device that separates and captures CO2 from combustion exhaust gas, the exhaust gas pretreatment facility comprising: an LDH reaction tower packed with a layered double hydroxide LDH; and a gas cooling tower that cools the combustion exhaust gas discharged from the LDH reaction tower with cooling water.

2. An exhaust gas pretreatment system according to claim 1, characterized in that the LDH is in a granular form.

3. An exhaust gas pretreatment system according to claim 2, wherein the diameter of the LDH particles is 0.5 to 4 mm, preferably 1.0 to 2.5 mm.

4. An exhaust gas pretreatment system as described in claim 1, characterized in that the LDH reaction tower is packed with the LDH so that it moves from top to bottom, and the LDH that has completed adsorption can be regenerated and supplied from the top of the LDH reaction tower.

5. An exhaust gas pretreatment system as described in claim 4, characterized in that the upper part of the LDH reaction tower is provided with an LDH supplying equipment for replenishing LDH having the ability to remove acidic gases, the lower part is provided with an LDH extractor for extracting LDH which has completed adsorption of acidic gases, and an LDH discharging equipment for discharging the extracted LDH.

6. An exhaust gas pretreatment facility as described in claim 5, characterized in that the discharge amount of the LDH discharger is controlled according to the pH of the condensed water in the condensed water tank of the gas cooling tower or the amount of pH adjuster supplied to the condensed water tank.

7. An exhaust gas pretreatment system according to claim 4, characterized in that a regeneration tank for carrying out the regeneration is provided below the LDH reaction tower.

8. An exhaust gas treatment facility, characterized in that the exhaust gas pretreatment facility according to claim 1 is provided in a bypass of a main line leading from an incinerator or boiler to a chimney.

9. An exhaust gas treatment facility, characterized in that the exhaust gas pretreatment facility according to claim 1 is provided in the middle of a main line leading from an incinerator or boiler to a chimney.

10. A method for separating and recovering CO2 using an exhaust gas pretreatment equipment as described in any one of claims 1 to 7, characterized in that the pH value of the cooling water in the gas cooling tower is monitored, and when it falls below a predetermined value, the LDH is regenerated or replaced.

11. A method for separating and recovering CO2 using an exhaust gas pretreatment equipment as described in any one of claims 1 to 7, characterized in that the amount of pH adjuster added, which is determined from the pH value of the cooling water in the gas cooling tower, is monitored, and when a predetermined value is exceeded, the LDH is regenerated or replaced.

Images