Method and apparatus for recovering carbon dioxide and nitrogen oxides from exhaust gases

Abstract

This solution addresses challenges such as improving the separation and recovery capacity of carbon dioxide and nitrogen oxides contained in exhaust gases generated during the combustion of various combustible materials, automating continuous operation, and post-treatment. [Solution] This invention provides a method and apparatus for separating and recovering carbon dioxide and nitrogen oxides as precipitates of alkaline carbonates and nitrates of alkali metals, and alkaline aqueous solutions containing alkali compounds of alkali metals of Group I of the periodic table, etc., in a chemical reaction by contacting and mixing them in a reaction tower. The alkaline aqueous solutions and alkaline aqueous solutions containing precipitates are circulated by a circulation pump from adjustment tank 1 → reaction tower 11 → storage tank 2 → adjustment tank 1, and carbon dioxide and nitrogen oxides are separated and recovered by continuous operation.

Description

[Technical Field]

[0001] This invention relates to carbon dioxide (CO2) and nitrogen oxides (NO2) contained in combustion exhaust gas (hereinafter simply referred to as exhaust gas) generated in large quantities during the combustion treatment of solid fuels, liquid fuels, gaseous fuels, and waste. x This invention relates to a method and apparatus for separating and recovering substances through continuous operation, and contributes to improving the global environment. [Background technology]

[0002] Currently, various proposals have been made regarding the removal of carbon dioxide and nitrogen oxides from exhaust gases. For example, according to Patent Document 1 concerning the removal of carbon dioxide and nitrogen oxides from exhaust gases, a proposal is presented for the treatment of exhaust gases discharged to the outside from the combustion chambers of passenger cars and diesel vehicles, concerning the removal of carbon dioxide and nitrogen oxides from the atmosphere using a batch-type purification device with an alkaline aqueous solution and a carbon dioxide removal filter. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2008-284543 [Overview of the project] [Problems that the invention aims to solve]

[0004] The conventional technologies described above do not address carbon dioxide (CO2) and nitrogen oxides (NO2) contained in exhaust gases generated in large quantities during the combustion of solid fuels, liquid fuels, gaseous fuels, and waste. x The ability to separate and recover these substances is small, and furthermore, the large amount of exhaust gas generated contains carbon dioxide (CO2) and nitrogen oxides (NOx). x Automated operation through continuous use is not feasible. Furthermore, no information is provided regarding the post-treatment of carbonate compounds and nitrogen compounds generated after separation and recovery, and depending on the composition of the components, the treatment method may lead to harm. The present invention aims to provide a processing method and apparatus for solving this problem. [Means for solving the problem]

[0005] The present invention, which aims to achieve the above objective, involves the combustion treatment of at least one combustible material from the group consisting of solid fuels, liquid fuels, gaseous fuels, and waste, and the carbon dioxide (CO2) and nitrogen oxides (NO2) contained in the exhaust gas generated in large quantities during this process. x In a reaction column, an alkaline aqueous solution consisting of alkaline compounds of alkali metals from Group I of the periodic table and an alkaline aqueous solution containing precipitates of alkaline compounds of alkaline earth metals from Group II of the periodic table are brought into contact and mixed to form a chemical reaction. This reaction produces precipitates of alkaline earth metal carbonates and aqueous solutions of nitrates, as well as aqueous solutions of alkali metal carbonates and nitrates, resulting in carbon dioxide (CO2) and nitrogen oxides (NO2). X This system separates and recovers alkaline aqueous solutions and alkaline aqueous solutions containing precipitates, etc., which are circulated by a circulation pump from a regulating tank → reaction tower → storage tank → regulating tank. This allows for continuous operation of carbon dioxide (CO2) and nitrogen oxides (NO2). x This invention provides a method and apparatus for separating and recovering [the substance]. [Effects of the Invention]

[0006] This invention provides continuous operation to remove carbon dioxide (CO2) and nitrogen oxides (NO2). x A method and apparatus for separating and recovering the material can be provided. According to the present invention, carbon dioxide and nitrogen oxides generated during the combustion process are recovered as carbonates and nitrates through a chemical reaction involving contact and mixing with an aqueous solution of an alkaline compound consisting of alkali metals and alkaline earth metals in a spray or shower-like manner. Preventing the emission of carbon dioxide and nitrogen oxides into the atmosphere contributes to preventing global warming and acid rain. Furthermore, the alkali metal and alkaline earth metal carbonates and nitrates obtained in the carbon dioxide and nitrogen oxide treatment process have properties as soil conditioners. They have a neutralizing effect on acidic soils. When carbonates and nitrates are mixed during composting, the carbon dioxide (-CO3) and nitrate (-NO3) generated simultaneously with the neutralization effect combine with ammonia (NH4OH) in the compost to form ammonium carbonate ((NH4)2CO3) and ammonium nitrate (NHNOg), which are fixed in the soil. This stabilizes the soil's pH and provides nutrients for plants, contributing to the prevention of global warming and acid rain. [Brief explanation of the drawing]

[0007] [Figure 1A] This diagram shows the structure in which the flows of exhaust gas and alkaline aqueous solution intersect within the reaction tower according to an embodiment of the present invention. The left side is an overall side view, the upper right is a top view of obstacle 15, and the lower right is a side view of obstacle 15. [Figure 1B] This diagram shows the flow of exhaust gas and alkaline aqueous solution within the reaction tower according to an embodiment of the present invention. The left side is an overall side view, the upper right is a top view of the spraying jig 16, and the lower right is a top view of the throttling jig 20. [Figure 1C] The diagram shows a "water storage tank" and a "regulating tank" according to an embodiment of the present invention, with the top image being a "side view" and the bottom image being a "top view" of them. [Figure 2A] This diagram shows the structure in which the flows of exhaust gas and alkaline aqueous solution intersect within the reaction tower according to an embodiment of the present invention. The left side is an overall side view, the upper right is a top view of the collection and distribution jig 13, and the lower right is a side view of the collection and distribution jig 13. [Figure 2B]This diagram shows the flow of exhaust gas and alkaline aqueous solution within a reaction tower according to an embodiment of the present invention. The left side is an overall side view, the upper right is a top view of obstacle 15, and the lower right is a side view of obstacle 15. [Figure 3A] This is an overall side view showing the structure in which the flows of exhaust gas and alkaline aqueous solution intersect within the reaction tower according to an embodiment of the present invention. [Figure 3B] This is an overall side view showing the structure configuration illustrating the flow of exhaust gas and alkaline aqueous solution within a reaction tower according to an embodiment of the present invention. [Figure 3C] The images show obstacle jigs installed inside a "reaction tower" according to an embodiment of the present invention. The first image from the top is a "top view" of one example (12-a), the second image from the top is a "side view" of one example (12-a), the third image from the top is a "top view" of another example (12-b), and the fourth image from the top is a "side view" of another example (12-b). [Figure 3D] This shows other examples of obstacle jigs installed in a "reaction tower" according to an embodiment of the present invention. The leftmost image from the top is a "top view" of one example (13), the rightmost image from the top is a "top view" of one example (13 and 15), the second image from the top is a "side view" of one example (13), and the third image from the top is a "side view" of one example (13 and 15). [Figure 3E] This shows an example of a collection passage installed in a "reaction tower" according to an embodiment of the present invention. The leftmost image from the top is a "top view" of the collection passage 14 in this example, the rightmost image from the top is a "side view" of the collection passage 14 in this example, the second image from the top is a "side view" showing the unfolded state of the strip-shaped obstacle 15 in this example, the third image from the top is a "top view" showing the example with one end of the unfolded strip-shaped obstacle 15 attached to the collection passage 14, the fourth image from the top is a "top view" showing the example with the unfolded strip-shaped obstacle 15 wrapped around the outside of the collection passage 14, and the fifth image from the top is a "side view" showing the example with the unfolded strip-shaped obstacle 15 wrapped around the outside of the collection passage 14. [Figure 4A]It shows the structure of the "reaction tower" according to the embodiment of the present invention, where the flow of "exhaust gas" and "alkaline aqueous solution" intersects. The left side is the overall "side view", the upper right is the "top view" of the throttle tool 13, and the lower right is the "side view" of the throttle tool 13. [Figure 4B] It shows the flow of "exhaust gas" and "alkaline aqueous solution" in the "reaction tower" according to the embodiment of the present invention. The left side is the overall "side view", the upper right is the "top view" of the obstacle 15, and the lower right is the "side view" of the obstacle 15. [Figure 5] It shows the structure of the "adjustment tank" and "water storage tank" shown in FIGS. 2, 3, and 4 according to the embodiment of the present invention. The upper is their "side view", and the lower is their "top view". [Figure 6] Process explanatory diagram showing the process flow according to the invention of claim 1. [Figure 7] Process explanatory diagram showing the process flow according to the invention of claim 2. [Figure 8] Process explanatory diagram showing the process flow according to the invention of claim 3.

Embodiments for Carrying Out the Invention

[0008] The present invention can be implemented in the following various forms. This will be sequentially described based on FIGS. 1, 2, 3, 4, 5, 6, 7, and 8. (Embodiment 1)

[0009] In Embodiment 1, an alkaline aqueous solution of potassium hydroxide (KOH), an alkali metal of Group I of the periodic table, is prepared in the adjustment tank 1. This alkaline aqueous solution is sprayed downward from the upper part of the reaction tower 11 with an obstacle installed by the circulation pump 7-a. In the case of "Figure 1", it is sprayed by the spraying tool 16, and in the case of "Figure 2, Figure 3, Figure 4", it is sprayed downward by the shower method. On the other hand, carbon dioxide and nitrogen oxides in the exhaust gas generated during the operation of the combustion device are inserted from the upper part of the reaction tower 11 in the case of "Figure 1", and inserted from the lower part of the reaction tower 11 in the case of "Figure 2, Figure 3, Figure 4". Due to the combined structure of the "throttling tool 13" installed in the reaction tower 11 of "Figure 1, Figure 4" or the obstacle 15 of "Figure 2, Figure 3" and the spraying tool 16 of the alkaline aqueous solution, the contact chemical reaction between the alkaline aqueous solution and carbon dioxide and nitrogen oxides in the exhaust gas is promoted by the "turbulence and / or fluctuation" of the liquid and gas, so that carbon dioxide becomes an aqueous solution of potassium carbonate, and nitrogen oxides become an aqueous solution of potassium nitrate, which is mixed with the alkaline aqueous solution of potassium hydroxide in the water storage tank 2, and the process flow of adjustment tank 1 → reaction tower 11 → water storage tank 2 → adjustment tank 1 is repeated as shown in "Figure 6".

[0010] During this period, potassium hydroxide (KOH), an alkali metal of Group I of the periodic table, is continuously added to the circulating alkaline aqueous solution under the control of "pH 8.0 or higher" to form a concentrated aqueous solution of potassium carbonate and potassium nitrate, which is separated from the water storage tank 2, and carbon dioxide and nitrogen oxides in the exhaust gas are separated and recovered as crystals by heating and concentration. (Embodiment 2)

[0011] In Embodiment 2, a mixed aqueous solution of calcium hydroxide crystals and an aqueous solution of calcium hydroxide, both alkaline earth metal elements of Group II of the periodic table, is prepared in the adjustment tank 1. This crystalline alkaline aqueous solution is then circulated by a circulation pump 7-a through the top of the reaction tower 11 (Figures 2, 3, and 4) equipped with obstacles 15, using a spraying jig 16 to spray the alkaline aqueous solution. The turbulent flow and / or wave action of the exhaust gas containing carbon dioxide and nitrogen oxides in the exhaust gas is introduced from the bottom of the reaction tower 11 to promote a catalytic chemical reaction. The carbon dioxide and nitrogen oxides are converted into calcium carbonate crystals and an aqueous solution of calcium nitrate, forming a mixed aqueous solution of calcium hydroxide. The process is repeated as shown in Figure 7, from adjustment tank 1 to reaction tower 11 to storage tank 2 and back to adjustment tank, and the calcium carbonate crystals are precipitated and accumulated. During this time, alkaline compounds of alkaline earth metals from Group II of the periodic table are continuously added to the alkaline aqueous solution under the control of maintaining a pH of "8.0 or higher".

[0012] The calcium carbonate crystals and precipitates accumulated in the water storage tank 2 are pumped up by the pumping pump 9 to the precipitate separation device 8 and separated. Meanwhile, the aqueous solution of calcium nitrate is repeatedly circulated and accumulated as a concentrated liquid. This concentrated liquid is heated and concentrated to form crystals, and carbon dioxide and nitrogen oxides in the exhaust gas are separated and recovered. (Embodiment 3)

[0013] Embodiment 3 involves preparing an alkaline aqueous solution containing sodium hydroxide (NaOH), an alkali metal element of Group I of the periodic table, and calcium hydroxide (Ca(OH)2), an alkaline earth metal element of Group II of the periodic table, in a preparation tank 1. The alkaline aqueous solution is then sprayed from the top of the reaction tower 11 (Figures 2, 3, and 4), which is equipped with obstacles 15, through a collection and distribution jig 13 using a circulation pump 7-a. The alkaline aqueous solution and carbon dioxide and nitrogen oxide gases from the exhaust gas, which are introduced from the bottom of the reaction tower 11, are then reacted with carbon dioxide and nitrogen oxides in a turbulent and / or wave-like manner due to the obstacle structure 15 and throttling jig 20 within the reaction tower 11, thereby promoting a catalytic chemical reaction. The carbon dioxide and nitrogen oxides are then converted into calcium carbonate. The mixture of calcium carbonate, sodium nitrate, sodium carbonate, and sodium nitrate forms an aqueous solution that circulates from reaction tower 11 to storage tank 2 and then to adjustment tank 1. In the adjustment tank, sodium carbonate and sodium nitrate undergo a substitution reaction with calcium hydroxide in adjustment tank 1 according to the "law of ionization tendency," with sodium carbonate becoming calcium carbonate and sodium hydroxide, and sodium nitrate becoming calcium nitrate. The process repeats from adjustment tank 1 to reaction tower 11 to storage tank 2 and back to adjustment tank 1 as shown in Figure 8, causing calcium carbonate crystals to grow and precipitate and accumulate in storage tank 2. The liquids of calcium nitrate, sodium hydroxide, and sodium nitrate are repeatedly circulated, concentrated, and accumulated. During this time, alkaline compounds of alkaline earth metals from Group II of the periodic table are continuously added to the circulating alkaline aqueous solution under the control of maintaining a pH of "8.0 or higher". In this method, calcium carbonate settled and accumulated in the water storage tank 2 is pumped up by the pumping pump 9 to the sediment separation device 8, where it is separated and recovered, and carbon dioxide and nitrogen oxides are separated and recovered from the exhaust gas. (Embodiment 4)

[0014] In Embodiment 4, an alkaline aqueous solution of potassium hydroxide (KOH), an alkali metal element of Group I of the periodic table, is prepared in the adjustment tank 1. This alkaline aqueous solution is sprayed downwards from the top of the reaction tower 11, which is equipped with obstacles, using a spray jig 16 via a circulation pump 7-a. Meanwhile, carbon dioxide and nitrogen oxides in the exhaust gas generated during the operation of the combustion device are introduced from the top of the reaction tower 11 as shown in "Figure 1". Inside the reaction tower 11, both liquid and gas move downwards in the same direction. The "throttling jig 13" installed in the reaction tower 11 promotes the catalytic chemical reaction between the alkaline aqueous solution and the liquid and gas carbon dioxide and nitrogen oxides in the exhaust gas through "turbulence and / or waves". The carbon dioxide becomes an aqueous solution of potassium carbonate, and the nitrogen oxides become an aqueous solution of potassium nitrate, which are then mixed with the alkaline aqueous solution of potassium hydroxide in the storage tank 2. The mixture is then circulated repeatedly from adjustment tank 1 → reaction tower 11 → storage tank 2 → adjustment tank 1 to become a concentrated aqueous solution.

[0015] During this time, potassium hydroxide (KOH), an alkali metal element from Group I of the periodic table, is constantly added to the circulating alkaline aqueous solution under the control of "pH 8.0 or higher" by the "alkaline compound quantitative dispensing device 3-a" installed in adjustment tank 1. This dissolves the KOH in the "dissolution basket 3-b" installed in adjustment tank 1, and the mixture is stirred by the "stirrer 4" to make the concentration uniform. The water level is sensed by the "level sensor 5" and supplied by the "automatic water supply 6". This device separates concentrated aqueous solutions of potassium carbonate and potassium nitrate from "Storage Tank 2," heats and concentrates them as crystals, and uses them to separate and recover carbon dioxide and nitrogen oxides from exhaust gas. (Embodiment 5)

[0016] Embodiment 5 involves preparing a mixed aqueous solution of calcium hydroxide (Ca(OH)2) crystals of alkaline earth metals from Group II of the periodic table in the adjustment tank 1. This alkaline aqueous solution is then distributed from the top of the reaction tower 11, which is equipped with obstacles, by a circulation pump 7-a to a collection and distribution jig 13 via a distribution jig 16, and showered downwards. Meanwhile, carbon dioxide and nitrogen oxides in the exhaust gas generated during the operation of the combustion device are introduced from the bottom of the reaction tower 11 as shown in "Figure 2". Through the cross-contact of gas and liquid within the alkaline aqueous solution and obstacles 15, the carbon dioxide is converted into calcium carbonate crystals, and nitrogen oxides are converted into nitrogen oxides. The calcium hydroxide solution becomes an aqueous solution of calcium nitrate and a mixed aqueous solution of calcium hydroxide and an alkaline aqueous solution. The mixture circulates repeatedly from reaction tower 11 to storage tank 2 to adjustment tank 1 and back to reaction tower 11, causing calcium hydroxide crystals to grow and settle in storage tank 2. The precipitate is then sent to the precipitate separation device 8 by the pump 9, where carbon dioxide is separated and recovered as calcium carbonate crystals. The aqueous solution of calcium nitrate, as an alkaline mixed aqueous solution of calcium hydroxide, is circulated repeatedly from storage tank 2 to adjustment tank 1 to reaction tower 11 and back to storage tank 2 by the circulation pump 7-a installed in adjustment tank 1, becoming a concentrated aqueous solution.

[0017] During this time, the circulating alkaline aqueous solution is constantly maintained at a pH of 8.0 or higher. Alkaline compound quantitative input device 3-a, installed in adjustment tank 1 (Figure 5), adds calcium hydroxide (Ca(OH)2), an alkaline earth metal element of Group II of the periodic table, to the "dissolving basket 3-b" installed in adjustment tank 1, where it dissolves. The mixture is then stirred by a stirrer 4 to ensure uniform concentration. The water level is detected by a level sensor 5, and the water level is stabilized by an automatic water supply system 6. The concentrated aqueous solution of calcium nitrate is separated from the storage tank 2, heated and concentrated to form crystals, and used in a device to separate and recover carbon dioxide and nitrogen oxides from the exhaust gas. (Embodiment 6)

[0018] In Embodiment 6, a mixed aqueous solution of calcium hydroxide (Ca(OH)2) crystals of alkaline earth metals from Group II of the periodic table is prepared in the adjustment tank 1. This alkaline aqueous solution is then distributed uniformly in 360 degrees by a distribution jig 16 and a dispersion jig 12 from the top of the reaction tower 11, where the obstacles shown in Figure 3 are installed, using a circulation pump 7-a. The alkaline aqueous solution flows downward, collected in a collection jig 13, and then flows downward and vertically from the top of the obstacles 15 "set" on the collection jig 13 in Figure 3E. The alkaline aqueous solution is again distributed uniformly in 360 degrees by the dispersion jig 12 and flows downward, collected in the collection jig 13, and this process is repeated within the reaction tower 11 as the solution flows downward and collects in the storage tank 2.

[0019] Carbon dioxide and nitrogen oxides in the exhaust gas rise from below the reaction tower 11, pass through the side of the obstacle 15, collect in the exhaust gas collection passage 14, rise within the passage, and the exhaust gas collects on the side of the next obstacle 15.

[0020] The catalytic chemical reaction between the alkaline aqueous solution and the liquid and gaseous carbon dioxide and nitrogen oxides in the exhaust gas is accelerated by "turbulence and / or waves," causing the carbon dioxide to crystallize into calcium carbonate, the nitrogen oxides to form an aqueous solution of calcium nitrate, and a mixed aqueous solution of calcium hydroxide and alkaline aqueous solution. This mixture circulates repeatedly from reaction tower 11 → storage tank 2 → adjustment tank 1 → reaction tower 11, causing the calcium hydroxide crystals to grow and settle in storage tank 2. The precipitate is then sent to the precipitate separation device 8 by the pump 9, where the carbon dioxide is separated and recovered as calcium carbonate crystals. The aqueous solution of calcium nitrate is then circulated repeatedly as an alkaline mixed aqueous solution of calcium hydroxide from storage tank 2 → adjustment tank 1 → reaction tower 11 → storage tank 2 by the circulation pump 7-a installed in adjustment tank 1, becoming a concentrated aqueous solution.

[0021] During this time, the circulating alkaline aqueous solution is constantly maintained at a pH of 8.0 or higher. Alkaline compound quantitative input device 3-a, installed in adjustment tank 1 (Figure 5), adds calcium hydroxide (Ca(OH)2), an alkaline earth metal from Group II of the periodic table, to the adjustment tank 1 (Figure 5), where it dissolves in the dissolution basket 3-b, which is also installed in adjustment tank 1. The mixture is then stirred by a stirrer 4 to ensure uniform concentration. The water level is monitored by a level sensor 5, and the water level is stabilized by an automatic water supply system 6. The concentrated aqueous solution of potassium nitrate is separated from the storage tank 2, heated and concentrated to form crystals, and used in the device to separate and recover carbon dioxide and nitrogen oxides from the exhaust gas. (Embodiment 7)

[0022] Embodiment 7 involves preparing an aqueous solution of calcium hydroxide (Ca(OH)2) crystals of alkaline earth metals from Group II of the periodic table in a conditioning tank 1. This alkaline aqueous solution is then uniformly distributed from the top of the reaction tower 11, which is equipped with the obstacles shown in Figure 4, by a circulation pump 7-a and a distribution nozzle 16-b through a shower fixture 13, showering downwards. Meanwhile, carbon dioxide and nitrogen oxides in the exhaust gas generated during the operation of the combustion device are introduced from the bottom of the reaction tower 11 shown in Figure 4 and pass through it. Due to the installation of the shower fixture 13 and the throttling fixture 20, gases and liquids come into contact under turbulent and intersecting conditions, resulting in contact chemistry through "turbulence and / or waves". As the reaction is accelerated, carbon dioxide is converted into calcium carbonate crystals, nitrogen oxides into an aqueous solution of calcium nitrate, and the mixed aqueous solution of calcium hydroxide and calcium hydroxide is circulated repeatedly from reaction tower 11 to storage tank 2 to adjustment tank 1 and back to reaction tower 11. The calcium hydroxide crystals grow and settle in storage tank 2, where they are pumped up to the precipitate separation device 8 by pump 9, and the carbon dioxide is separated and recovered as calcium carbonate crystals. The aqueous solution of calcium nitrate is circulated repeatedly as an alkaline mixed aqueous solution of calcium hydroxide from storage tank 2 to adjustment tank 1 to reaction tower 11 and back to storage tank 2 by the circulation pump 7-a installed in adjustment tank 1, becoming a concentrated aqueous solution.

[0023] During this time, the circulating alkaline aqueous solution is constantly maintained at a pH of 8.0 or higher. Calcium hydroxide (Ca(OH)2), an alkaline earth metal from Group 3 of the periodic table, is added to the "dissolution basket 3-b" installed in the adjustment tank 1 (Figure 5) by the "alkaline compound quantitative input device 3-a" located in the adjustment tank 1 (Figure 5) and dissolved. The mixture is then stirred by the "stirrer 4" to ensure uniform concentration. The water level is detected by the "level sensor 5" and stabilized by the "automatic water supply 6". Furthermore, a concentrated aqueous solution of potassium nitrate is separated from the "storage tank 2", heated and concentrated to form crystals, which are used to separate and recover carbon dioxide and nitrogen oxides from the exhaust gas. (Explanation of each part)

[0024] Details of the above embodiments will be explained with reference to the figures, but the present invention should not be understood as being limited to these embodiments.

[0025] The reaction tower 11 in "Figure 1A" is constructed as a vertically elongated cylinder by connecting cylindrical bodies with connecting flanges 21, and its upper end is closed. Exhaust gas 18 is guided to the top of the reaction tower 11 through the exhaust gas pipe 10. Inside the reaction tower 11, an obstacle 15 is placed in the collection passage 14 below the spreading jig 16a. Constriction jigs 20 are placed around the top and bottom of the obstacle 15. In the example shown in "Figure 1A," the spreading jig 16a, obstacle 15, and constricting jig 20 are arranged in three stages, but one stage is also acceptable, or the number can be changed to any other number of stages.

[0026] The spraying jig 16a sprays the alkaline solution 17 in a shower or mist manner toward the obstacles 15 below. More specifically, as shown in "Figure 1B", it is preferable to set the number of spraying jigs 16a so that the solution is evenly distributed across the spraying area. The configuration of the spraying jig 16a can be implemented in various forms that can supply the alkaline solution 17 to the obstacles 15 in the collection passage 14 in a uniformly dispersed state. As shown in Figure 1B, the throttling jig 20 has an opening in the center of the narrowed collection passage 14 and controls the flow rate of the fluid passing through it. By throttling the flow rate, it is advantageous in that it can improve the contact mixing of gas and liquid due to fluctuations in gas air pressure, waves and turbulence, and thus promote the substitution reaction.

[0027] As shown in Figure 3E, the obstacle 15 is a strip-shaped obstacle 15 wrapped multiple times around the outside of the jig of the collection passage 14, which has multiple leg sections extending downward from the upper cylindrical section. The obstacle 15 is made of a heat-resistant, chemical-resistant, and breathable strip of metal or resin, and multiple partition rods extending vertically are attached to the strip at intervals along its longitudinal direction. This configuration is advantageous because, with respect to the liquid passing through the collection passage 14 and the obstacle 15, the direction of gas flow intersects, and the turbulent flow of liquid / gas exerts the effect of a "substitution chemical reaction".

[0028] As shown in Figure 2A, the collection / shower fixture 13 can also be implemented as a plate-like structure, such as a semicircular shape, with multiple through holes. The collection / shower fixture 13 is positioned in a portion of the collection passage 14 (approximately half in this example), while the other portion is an open passage. The position of the collection / shower fixture 13 differs at each stage, thereby preventing the fluid from moving in a straight line.

[0029] As shown in each figure of "Figure 3," particularly "Figure 3C," the obstacle jig (12-a) and the obstacle jig (12-b) may be combined. As shown in "Figure 3A" and "Figure 3B," jig (12-a) is placed on top of jig 13 in "Figure 3A," and jig 13 is positioned on top of the obstacle 15. Jig (12-b) is positioned on the bottom of the obstacle 15. Such jig (12-a) is cylindrical in shape with a gradually decreasing diameter towards the top, and its upper end is a liquid distribution jig with radial slits. Jig (12-b) is cylindrical in shape with a gradually decreasing diameter towards the top, and its upper end is flat.

[0030] These jigs (12-a) and (12-b) are used together with the collection and delivery jig 13 shown in "Figure 3D". The collection and delivery jig 13 is cylindrical in shape, with its diameter gradually increasing towards the top. By implementing these methods in combination, carbon dioxide (CO2) and nitrogen oxides (NOx) in exhaust gases can be reduced. x This has the effect of promoting the "substitution chemical reaction" between the alkaline solution and the substance. As shown in Figures 4A and 4B, the procedure may also be carried out by adding a plate-shaped drawing jig 13 with numerous through holes. [Examples]

[0031] The following examples will be described, but the present invention should not be understood as being limited to these examples. (Example 1)

[0032] Example 1 shows an embodiment of the invention described in claim 1. The experimental conditions for the example are shown at the top of Table 1 below, and the data for the recovery of carbon dioxide and nitrogen oxides are shown at the bottom of the same table.

[0033] [Table 1] (Example 2)

[0034] Example 2 shows an example according to the invention described in claim 2. The experimental conditions of the example are shown at the upper part of Table 2 below, and the recovery experiment data of carbon dioxide and nitrogen oxides are shown at the lower part of the same table.

[0035]

Table 2

[0036] Example 3 shows an example according to the invention described in claim 3. The experimental conditions of the example are shown at the upper part of Table 3 below, and the recovery experiment data of carbon dioxide and nitrogen oxides are shown at the lower part of the same table.

[0037]

Table 3

[0038] · The numerical values of the component concentrations of the exhaust gas, carbon dioxide (CO2) and nitrogen oxides (NO x ) generated during the operation of the combustion device are low because, for propane (C3H8), the air blowing volume is as much as 2 m 3 / min and the exhaust gas is diluted. Therefore, it is considered that the components of carbon dioxide (CO2) and nitrogen oxides (NO x ) are large in total generated amount. · The generation of carbon monoxide (CO) is not confirmed due to the remaining oxygen (O2). · Since the temperature in the combustion furnace is as high as 800 °C or more, the existing nitrogen (N2) is oxidized, so the generation amount of nitrogen oxides (NO x ) is large.

Explanation of reference signs

[0039] 1: Adjustment tank 2: Water storage tank 4: Stirrer 6: Automatic water supply 8: Precipitate separation device 9: Precipitate pumping pump 11: Reaction tower 12: Dispersion jig 13: Collection and delivery jigs, shower jigs, squeezing jigs 14: Collection route 15: Obstacles 16: Spraying jigs, spraying jigs, distribution jigs 20: Drawing jig

Claims

1. A process of introducing exhaust gas generated during the combustion treatment of at least one combustible material from the group consisting of solid fuels, liquid fuels, gaseous fuels, and waste into a reaction tower, The system comprises a reaction step of applying an alkaline aqueous solution to the exhaust gas by spraying or showering it, either alone or in combination, to cause a catalytic chemical reaction with the carbon dioxide and nitrogen oxides contained in the exhaust gas. The reaction step includes a step of promoting a chemical reaction between the exhaust gas and the alkaline aqueous solution by turbulent gaseous and / or wave-like flow of the gas and liquid, by applying the alkaline aqueous solution by spraying or showering, either alone or in combination. The aforementioned alkaline aqueous solution is an alkaline aqueous solution composed of an alkaline compound made up of alkali metals of Group I elements of the periodic table. The aforementioned reaction tower is equipped with obstacles for the purpose of promoting the reaction. A method for recovering carbon dioxide and nitrogen oxides from exhaust gas, characterized in that the alkaline aqueous solution is continuously circulated while the alkaline compound is constantly added to the alkaline aqueous solution under the control of "pH 8.0 or higher," and the alkaline aqueous solution is circulated so that it returns to the storage tank after passing through a regulating tank → reaction tower → storage tank, and the operation is carried out continuously, and the carbonates and nitrates of the alkali metals of Group I elements of the periodic table produced by the reaction process are separated from the exhaust gas as concentrated liquids, thereby separating and recovering carbon dioxide and nitrogen oxides from the exhaust gas.

2. A process of introducing exhaust gas generated during the combustion treatment of at least one combustible material from the group consisting of solid fuels, liquid fuels, gaseous fuels, and waste into a reaction tower, The process comprises a reaction step in which an alkaline aqueous solution containing powder of an alkaline compound composed of alkaline earth metals of Group II of the periodic table is applied to the exhaust gas by spraying, showering, or using either the solution alone or in combination, causing a catalytic chemical reaction with the carbon dioxide and nitrogen oxides contained in the exhaust gas. A method for recovering carbon dioxide and nitrogen oxides from exhaust gas, characterized in that obstacles are installed to promote the chemical reaction between the exhaust gas and the alkaline aqueous solution due to gas / liquid turbulence and / or waves, the alkaline aqueous solution is constantly maintained at a pH of 8.0 or higher, the alkaline compound of an alkaline earth metal is constantly added, the alkaline aqueous solution is circulated between a "regulating tank → reaction tower → storage tank → the regulating tank" and operated continuously, and through the reaction process, carbon dioxide is separated and recovered from the exhaust gas as a precipitate grown as a crystal of carbonate of the alkaline earth metal of Group II elements of the periodic table, and nitrogen oxides are separated and recovered from the exhaust gas as a concentrated aqueous solution of nitrate of the alkaline earth metal of Group II elements of the periodic table.

3. A process of introducing exhaust gas generated during the combustion treatment of at least one combustible material from the group consisting of solid fuels, liquid fuels, gaseous fuels, and waste into a reaction tower, The exhaust gas is then sprayed, showered, or otherwise applied to it by an alkaline aqueous solution containing powder of alkaline earth metals from Group II of the periodic table, in addition to an alkaline aqueous solution of alkali metals from Group I of the periodic table. A method for recovering carbon dioxide and nitrogen oxides from exhaust gas, characterized in that obstacles are installed to promote the chemical reaction in the reaction tower by turbulent gaseous and / or liquid wave motion with the alkaline aqueous solution to the carbon dioxide and nitrogen oxides contained in the exhaust gas; alkaline compounds of alkaline earth metals of Group II of the periodic table are constantly added to the alkaline aqueous solution under control of pH 8.0 or higher; the alkaline aqueous solution is repeatedly circulated from a regulating tank to a reaction tower to a storage tank to a regulating tank; the carbon dioxide becomes a precipitate of alkaline earth metal carbonate through the chemical reaction process in the reaction tower and is recovered as precipitate in the storage tank; on the other hand, the nitrogen oxides become an aqueous solution of alkaline earth metal nitrate and are repeatedly circulated from a regulating tank to a reaction tower to a storage tank to a regulating tank to a regulating tank to a nitrate concentrate, and are separated and recovered from the exhaust gas.

4. An apparatus for recovering carbon dioxide and nitrogen oxides from exhaust gas, characterized in that it comprises at least the adjustment tank, the reaction tower, and the water storage tank used when carrying out the method for recovering carbon dioxide and nitrogen oxides from exhaust gas according to any one of claims 1 to 3.

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