A flue gas desulfurization and decarburization absorbent and a preparation and application method thereof

Abstract

The application discloses a flue gas desulfurization and decarburization absorbent, and a preparation and application method thereof. The absorbent is prepared by mixing absorbent 1 and absorbent 2 at a volume ratio of 1:10-1:20. The absorbent 1 is Ca(OH)2 slurry with a concentration of 10-15%wt. The absorbent 2 is prepared from a base solvent, active amine, water, corrosion inhibitor and antioxidant at a mass ratio of 3:1:6:0.015:0.005. The application can realize simultaneous desulfurization and decarburization in a spray absorption tower, is convenient to operate, and reduces equipment investment cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of atmospheric pollution coordinated control, and particularly relates to a formula of an absorbent for simultaneous flue gas desulfurization and decarburization and application thereof. BACKGROUND

[0002] For a long time, the primary energy consumption in China is still dominated by coal. The atmospheric pollutants in coal-fired flue gas cause serious harm to the environment, mainly including SO2, NOx, and particulate matter, etc. With the deep treatment of air pollution, SO2, NOx, and total suspended particulate matter, etc. have been basically effectively controlled, but air pollution has not been completely eliminated. With the introduction of the policies of carbon peak and carbon neutrality, CO2 emission reduction has become the primary task in the next few decades under low carbon. Since SO2 and CO2 are both acidic gases and easily soluble in water, they can be removed by alkali absorption.

[0003] The technology of alkali absorption for removing SO2 is the wet flue gas desulfurization technology, which mainly uses the absorbent to remove SO2 in the flue gas and convert it into stable sulfur compounds. This technology is a gas-liquid reaction, with fast reaction speed, high desulfurization efficiency, and mature technology. The limestone / lime method accounts for 80% of the wet desulfurization and is the basic process for flue gas desulfurization in large power plant units internationally. The desulfurization absorbent of this method is cheap and readily available limestone or lime, which is crushed, ground, and mixed with water to form an absorbent slurry. The absorption slurry and flue gas are countercurrently contacted in the absorption tower. SO2 in the flue gas is removed by acid-base neutralization reaction with the absorption liquid, and the generated calcium sulfite is oxidized to gypsum in the oxidation tank. After the desulfurized flue gas entrains fine droplets, it is treated by a demister and then heated by a heat exchanger before being discharged into a chimney. The desulfurized gypsum slurry is dewatered by a dewatering device and then recovered. Due to the recycling of the absorption slurry, the utilization rate of the desulfurization absorbent is very high. Since the coal-fired flue gas contains about 12-15% CO2, its concentration is much higher than that of SO2. In the limestone / lime wet desulfurization process, it may react with Ca(OH)2 to generate CaCO3 precipitate, i.e. CO2 calcification scaling, which seriously affects the reliability of the system operation. The initial pH value of the absorption liquid is a major factor affecting the generation of CaCO3.

[0004] The technology of alkali absorption for removing CO2 is the chemical absorption method, which has high absorption efficiency, large treatment capacity, mature technology, and relatively low cost, and has become the mainstream technology for flue gas carbon capture. Domestic and foreign carbon capture demonstration projects all use the chemical absorption method, and the absorbent is generally an organic amine chemical solvent. However, amine absorbents are prone to degradation, especially alcohol amines. When the organic amine absorbent is desorbed under high temperature conditions, it reacts with O2, CO2, SOx, and NOx in the flue gas to generate by-products, which not only reduces the absorption capacity of the absorbent, but also causes corrosion of the equipment. xContact will cause the amine to undergo self-thermal degradation or chemical degradation, resulting in a decrease in CO2 capture efficiency, as well as problems such as absorbent loss, increased operating costs, and by-product corrosion of equipment. The most widely studied absorbents currently include monoethanolamine (MEA), diethanolamine (DEA), N-ethyl ethanolamine (EMEA), 2-amino-2-methyl-1,3-propanediol (AMPD), 2-amino-2-methyl-1-propanol (AMP), dimethyl ethanolamine (MDEA), and diethylamino ethanol (DEEA). The capture capacity and desorption energy consumption decrease in the above order, among which the steric hindrance amine can balance the capture efficiency and regeneration energy consumption. By compounding various types of amines according to their characteristics and adding antioxidants, corrosion inhibitors and other ingredients, an absorbent with superior performance can be obtained.

[0005] In summary, by combining the lime wet desulfurization technology and the alcohol amine absorption carbon capture technology, a composite absorption liquid is prepared with lime slurry and alcohol amine as the main components, and antioxidants, corrosion inhibitors and other ingredients are added to regulate the initial pH value and temperature of the absorption liquid, etc. A formula of an absorbent for simultaneous flue gas desulfurization and decarbonization can be obtained.

[0006] CN109432990A discloses a desulfurization and decarbonization absorbent, which comprises complex iron, an organic solvent and an organic base, wherein: the mass content of iron is 0.3-10 g / L, and the mass content of the organic base is 0-100 g / L; the complex iron comprises 1-butyl-3-methyl imidazole ethylenediamine iron tetraacetate, ethylenediamine tetraacetate ammonium iron and ethylenediamine tetraacetate sodium iron; the organic solvent comprises dimethyl sulfoxide or polyethylene glycol dimethyl ether or a mixture of the two; the organic base can be dissolved in the organic solvent, and specifically comprises 1-butyl-3-methyl imidazole hydroxide. The absorbent uses a non-aqueous solution of complex iron to avoid degradation of the complexing agent and reduce the cost of liquid phase catalytic oxidation. The absorbent liquid physically absorbs carbon dioxide while oxidizing and absorbing hydrogen sulfide, thereby reducing the equipment cost of absorption.

[0007] CN107376586A discloses an effective method for flue gas desulfurization and decarbonization, which specifically comprises the following steps: first, diethyl succinate is added to diethyl carbonate and stirred to mix uniformly to prepare an adsorbent A; then, carbon fiber loaded with magnesium chloride is used as an adsorbent B; the flue gas is dedusted; the dedusted flue gas is introduced into an adsorption tower and sequentially passes through the adsorbent B and the adsorbent A; the treated gas is discharged into the atmosphere; the adsorbent A and the adsorbent B are reused after desorption under reduced pressure; the desorbed gas is absorbed in ammonia water; and the generated sulfates and carbonates are recovered. The method provided by the present application has high desulfurization and decarbonization efficiency, does not cause secondary pollution to the atmosphere, has large adsorption capacity of the adsorbent, small solvent loss, and low treatment cost. SUMMARY

[0008] The application aims to provide a formula and application of a flue gas desulfurization and decarburization absorbent, so as to realize one-step desulfurization and decarburization by using a composite absorbent.

[0009] A flue gas desulfurization and decarburization absorbent is prepared by mixing absorbent 1 and absorbent 2 at a volume ratio of 1:10-1:20, wherein the absorbent 1 is Ca(OH)2 slurry with a concentration of 10-15%wt, and the absorbent 2 is composed of a base solvent, an active amine, water, an inhibitor and an antioxidant at a mass ratio of 3:1:6:0.015:0.005.

[0010] The base solvent is hydroxyethylethylenediamine (AEEA); the active amine is piperazine (PZ); the antioxidant is acetaldoxime (AAO); and the inhibitor is a mixed solution of sodium molybdate and zinc acetate, and the mass ratio of sodium molybdate to zinc acetate is 4:1.

[0011] A preparation method of a flue gas desulfurization and decarburization absorbent, comprising the following steps:

[0012] Step 1: lime and water are prepared into Ca(OH)2 slurry with a concentration of 10-15%wt as absorbent 1;

[0013] Step 2: a base solvent, an active amine, water, an inhibitor and an antioxidant are mixed at a mass ratio of 3:1:6:0.015:0.005 to obtain absorbent 2, wherein the base solvent is hydroxyethylethylenediamine (AEEA), the active amine is piperazine (PZ), the antioxidant is acetaldoxime (AAO), and the inhibitor is a mixed solution of sodium molybdate and zinc acetate, and the mass ratio of sodium molybdate to zinc acetate is 4:1;

[0014] Step 3: absorbent 1 and absorbent 2 are prepared and mixed into a mixed solution at a volume ratio of 1:10-1:20, and an acid-base buffer solution is used to adjust the pH to 11, so as to obtain the finished product.

[0015] In step 3, if the pH value of the mixed solution is <11, a saturated Ca(OH)2 solution is selected as the acid-base buffer solution, so as to adjust the pH to 11 and also serve as a SO2 absorbent; if the pH value of the mixed solution is >11, an acetic acid (HAC) solution is selected as the acid-base buffer solution, so as to adjust the pH to 11 and also react with Ca(OH)2 to generate calcium acetate which can serve as a CO2 absorbent.

[0016] An application method of a flue gas desulfurization and decarburization absorbent, comprising the following steps:

[0017] Step 1: The flue gas desulfurization and decarburization absorbent is loaded into a circulating tank, and the flue gas desulfurization and decarburization absorbent is delivered to the top of the tower by a pump and sprayed uniformly, and is in countercurrent contact with the flue gas entering the bottom, Ca(OH)2 in the flue gas desulfurization and decarburization absorbent reacts with SO2 to generate CaSO3, AEEA and PZ in the absorbent react with CO2 to generate carbonate, and the purified flue gas is discharged from the chimney after demisting and reheating;

[0018] Step 2: The absorbent after absorption flows back to the oxidation tank at the bottom, and CaSO3 is oxidized to CaSO4 under the condition of air blowing, and then crystallized into gypsum (CaSO4·2H2O), and after the gypsum slurry is separated from the absorbent, subsequent treatments such as dehydration are carried out, and the separation of the desulfurization product is completed;

[0019] Step 3: The absorbent separated from the gypsum slurry is delivered to the rich-lean liquid heat exchanger by a rich liquid pump for heat exchange, and then enters the regeneration tower, and under the action of heating, the carbonate decomposes to desorb CO2, the desorbed CO2 enters the subsequent purification and liquefaction process, the absorbent is changed from rich liquid to lean liquid and thus the regeneration is completed, and the regenerated absorbent returns to the circulating tank to supplement fresh lime slurry, and then the flue gas desulfurization and decarburization can be continuously carried out.

[0020] In step 1, the SO2 concentration in the flue gas is 4000 ppm, the CO2 concentration is 12%, the liquid / gas ratio is 4.7 L / m 3 , and the gas velocity is 3.0 m / s.

[0021] In step 2, the oxidation air is blown into the oxidation tank by a Roots blower, and the pressure is 5x10 4 Pa, in order to ensure that the CaSO3 slurry is in full contact with the air, a plurality of stirrers are arranged in the tank to keep the slurry in a flowing state, and the oxidation air is distributed near the stirrers by a spray pipe to optimize the airflow distribution, and the residence time of the absorbent in the oxidation tank is 4-8 min.

[0022] In step 3, the heating medium for the regeneration of the absorbent is water vapor, and the temperature is 100℃-102℃.

[0023] The present application adopts the classic limestone / lime slurry as the SO2 absorbent, and the alcohol amine as the CO2 absorbent, and the two are prepared into a composite absorbent, and by adjusting the initial pH value and temperature of the absorbent and other conditions, the CO2 calcification and scaling in the process of Ca(OH)2 absorbing SO2 is avoided; in order to solve the problems of oxidation loss and corrosion of equipment in the process of absorbing and desorbing CO2, antioxidant and corrosion inhibitor and other components are added, and a formula and application of a flue gas desulfurization and decarburization absorbent are obtained.

[0024] The present application has the following advantages:

[0025] (1) The desulfurization and decarburization absorbent is combined with lime wet desulfurization technology and alcohol amine absorption method carbon capture technology, Ca(OH)2 slurry is used as SO2 absorbent, and a compounded amine solution is used as CO2 absorbent, and the two are mixed according to a certain volume ratio to prepare the absorbent, and an acid-base buffer solution is used to adjust the pH to 11, so that desulfurization and decarburization can be realized at the same time, and the conversion of Ca(OH)2 into CaCO3 precipitate by the competitive reaction of CO2 and SO2 in flue gas is avoided, the calcification and scaling phenomenon of CO2 is inhibited, and the reliability of the system operation is ensured.

[0026] (2) The desulfurization and decarburization by-products of the absorbent are CaSO3 and alcohol amine carbonate respectively, both of which are in a dissolved state and are difficult to separate, CaSO3 is oxidized to CaSO4 under the condition of blast, and then crystallized into solid gypsum, so that the effective separation of the desulfurization and decarburization by-products is realized.

[0027] (3) The absorption liquid separated from the gypsum slurry is subjected to carbonate decomposition reaction under the action of heating to desorb CO2, the regeneration of the absorbent is completed, and high-purity desulfurization gypsum and CO2 gas are obtained, which has certain economic benefits.

[0028] (4) The desulfurization and decarburization method can be transformed on the basis of the original flue gas desulfurization system, and simultaneous desulfurization and decarburization can be realized in one spray absorption tower, which is convenient to operate and reduces the equipment investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The composition structure diagram of the desulfurization and decarburization absorbent provided by the present application is shown. DETAILED DESCRIPTION

[0031] The present application will be further described below in combination with the drawings and specific embodiments.

[0032] Embodiment 1

[0033] (1) Lime and water are added to the liquid preparation tank 1 to prepare Ca(OH)2 slurry with a concentration of 10-15%wt as SO2 absorbent;

[0034] (2) The complex amine solution is prepared in the solution preparation tank 2 as the CO2 absorbent, and the complex amine solution is composed of a base solvent, an active amine, an inhibitor and an antioxidant, wherein the base solvent is hydroxyethylethylene diamine (AEEA), the active amine is piperazine (PZ), the antioxidant is acetaldoxime (AAO), and the inhibitor is a mixed solution of sodium molybdate and zinc acetate, and the mass ratio of AEEA: PZ: H2O: AAO: sodium molybdate: zinc acetate is 3: 1: 6: 0.015: 0.004: 0.001;

[0035] (3) The SO2 absorbent and the CO2 absorbent are mixed in a volume ratio of 1:10 to prepare a mixed solution, and an acid-base buffer solution is used to adjust the pH to 11; if the pH value of the mixed solution is < 11, a saturated Ca(OH)2 solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also serve as the SO2 absorbent; if the pH value of the mixed solution is > 11, an acetic acid (HAC) solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also react with Ca(OH)2 to generate calcium acetate that can serve as the CO2 absorbent; thus, the prepared desulfurization and decarbonization absorbent is marked as AbSC-11-10;

[0036] (4) The desulfurization and decarbonization is carried out in the spray tower, the above-mentioned desulfurization and decarbonization absorbent is loaded into the circulating tank, and the absorbent is pumped to the top of the tower and uniformly sprayed out to contact with the flue gas entering from the bottom in countercurrent, the SO2 concentration in the flue gas is about 4000 ppm, the CO2 concentration is about 12%, the liquid / gas ratio is 4.7 L / m 3 , and the gas velocity is 3.0 m / s; Ca(OH)2 in the absorption liquid reacts with SO2 to generate CaSO3, and AEEA and PZ in the absorption liquid react with CO2 to generate carbonate, thus completing the flue gas desulfurization and decarbonization, and the purified flue gas is discharged from the chimney after demisting and reheating;

[0037] (5) The absorption liquid after completing the absorption process flows back to the oxidation tank at the bottom, and CaSO3 is oxidized to CaSO4 under the condition of air blowing, the oxidation air is blown into the oxidation tank by a Roots blower, and the pressure is about 5x10 4 Pa; in order to ensure that the CaSO3 slurry is in full contact with the air, a plurality of stirrers are arranged in the tank to keep the slurry in a flowing state, the oxidation air is distributed near the stirrers by a spray pipe to optimize the air flow distribution, the residence time of the absorbent in the oxidation tank is about 4-8 min, and then CaSO3 is crystallized into gypsum (CaSO4·2H2O), and the gypsum slurry is separated from the absorption liquid and then subjected to subsequent treatment such as dewatering, thus completing the separation of the desulfurization product;

[0038] (6) The absorption liquid separated from the gypsum slurry is transported to the lean-rich liquid heat exchanger by the rich liquid pump for heat exchange, and then enters the regeneration tower. The absorption liquid is heated by 100°C-102°C water vapor, and the carbonate decomposes to desorb CO2 under the action of heating. The desorbed CO2 enters the subsequent purification and liquefaction process, and the absorption liquid is converted from rich liquid to lean liquid, thereby completing regeneration. The regenerated absorption liquid returns to the circulating tank, and fresh lime slurry is added to continue the flue gas desulfurization and decarburization.

[0039] Example 2

[0040] (1) Lime and water are added to the liquid preparation tank 1 to prepare a Ca(OH)2 slurry with a concentration of 10-15%wt as an SO2 absorption agent;

[0041] (2) A complex amine solution is prepared in the liquid preparation tank 2 as a CO2 absorption agent. The complex amine solution is composed of a base solvent, an active amine, an corrosion inhibitor and an antioxidant. The base solvent is hydroxyethyl ethylenediamine (AEEA), the active amine is piperazine (PZ), the antioxidant is acetaldoxime (AAO), and the corrosion inhibitor is a mixed solution of sodium molybdate and zinc acetate with a mass ratio of AEEA: PZ: H2O: AAO: sodium molybdate: zinc acetate = 3: 1: 6: 0.015: 0.004: 0.001;

[0042] (3) The above-mentioned SO2 absorption agent and CO2 absorption agent are prepared into a mixed solution with a volume ratio of 1:15, and an acid-base buffer solution is used to adjust the pH to 11. If the pH value of the mixed solution is <11, saturated Ca(OH)2 solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also serve as an SO2 absorption agent. If the pH value of the mixed solution is >11, acetic acid (HAC) solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also react with Ca(OH)2 to generate calcium acetate that can be used as a CO2 absorption agent. The thus-prepared desulfurization and decarburization absorption agent is marked as AbSC-11-15;

[0043] (4) Desulfurization and decarburization are carried out in the spray tower. The above-mentioned desulfurization and decarburization absorption agent is loaded into the circulating tank, and the absorption agent is transported to the top of the tower by a pump and sprayed uniformly, and countercurrently contacted with the flue gas entering from the bottom. The SO2 concentration in the flue gas is about 4000 ppm, the CO2 concentration is about 12%, the liquid / gas ratio is 4.7 L / m 3 , and the gas velocity is 3.0 m / s. Ca(OH)2 in the absorption liquid reacts with SO2 to generate CaSO3, and AEEA and PZ in the absorption liquid react with CO2 to generate carbonate, thereby completing flue gas desulfurization and decarburization. The purified flue gas is discharged from the chimney after demisting and reheating;

[0044] (5) The absorption liquid that has completed the absorption process is returned to the oxidation tank at the bottom of the tower, and CaS03 is oxidized to CaS04 under the condition of air blowing. The oxidation air is blown into the oxidation tank by a Roots blower, and the pressure is about 5x10 4 Pa, in order to ensure that the CaS03 slurry is in sufficient contact with the air, a plurality of mixers are arranged in the tank to keep the slurry in a flowing state. The oxidation air is arranged near the mixers through a spray pipe to optimize the airflow distribution. The residence time of the absorbent in the oxidation tank is about 4-8 min, and then CaS03 crystallizes into gypsum (CaS04·2H20). After the gypsum slurry is separated from the absorption liquid, subsequent treatments such as dewatering are performed, thereby completing the separation of the desulfurization product;

[0045] (6) The absorption liquid separated from the gypsum slurry is transported to the rich-lean liquid heat exchanger for heat exchange, and then enters the regeneration tower. The absorbent is heated by 100°C-102°C water vapor, and under the action of heating, the carbonate decomposes to desorb CO2. The desorbed CO2 enters the subsequent purification and liquefaction process, the absorbent changes from rich liquid to lean liquid, and thus the regeneration is completed. The regenerated absorbent returns to the circulating tank to supplement fresh lime slurry, and then the flue gas desulfurization and decarbonization can continue.

[0046] Example 3

[0047] (1) Lime and water are added to the liquid preparation tank 1 to prepare a Ca(OH)2 slurry with a concentration of 10-15%wt as an SO2 absorbent;

[0048] (2) A complex amine solution is prepared in the liquid preparation tank 2 as a CO2 absorbent. The complex amine solution is composed of a base solvent, an active amine, an corrosion inhibitor and an antioxidant. The base solvent is hydroxyethyl ethylenediamine (AEEA), the active amine is piperazine (PZ), the antioxidant is acetaldoxime (AAO), and the corrosion inhibitor is a mixed solution of sodium molybdate and zinc acetate with a mass ratio of AEEA: PZ: H2O: AAO: sodium molybdate: zinc acetate = 3: 1: 6: 0.015: 0.004: 0.001;

[0049] (3) The above-mentioned SO2 absorbent and CO2 absorbent are prepared into a mixed solution with a volume ratio of 1:20, and an acid-base buffer solution is used to adjust the pH to 11. If the pH value of the mixed solution is <11, saturated Ca(OH)2 solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also serve as an SO2 absorbent. If the pH value of the mixed solution is >11, acetic acid (HAC) solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also react with Ca(OH)2 to generate calcium acetate that can be used as a CO2 absorbent. The thus-prepared desulfurization and decarbonization absorbent is marked as AbSC-11-20;

[0050] (4) in the spray tower, the desulfurization and decarburization absorbent is loaded into the circulating tank, the absorbent is pumped to the top of the tower and sprayed uniformly, and is contacted with the flue gas entering from the bottom in countercurrent, the SO2 concentration in the flue gas is about 4000ppm, the CO2 concentration is about 12%, the liquid / gas ratio is 4.7L / m 3 , and the gas velocity is 3.0m / s; Ca(OH)2 in the absorbent reacts with SO2 to generate CaSO3, AEEA and PZ in the absorbent react with CO2 to generate carbonate, thereby completing the flue gas desulfurization and decarburization, and the purified flue gas is discharged from the chimney after demisting and reheating;

[0051] (5) the absorbent completing the absorption process flows back to the oxidation tank, CaSO3 is oxidized to CaSO4 under the condition of air blowing, the oxidation air is blown into the oxidation tank by a Roots blower, the pressure is about 5x10 4 Pa, in order to ensure that the CaSO3 slurry is in full contact with the air, a plurality of agitators are arranged in the tank to keep the slurry in a flowing state, the oxidation air is arranged near the agitators by a spray pipe to optimize the air distribution, the residence time of the absorbent in the oxidation tank is about 4-8min, then CaSO3 crystallizes into gypsum (CaSO4·2H2O), the gypsum slurry is separated from the absorbent, and then dehydration and subsequent treatment are performed, thereby completing the separation of the desulfurization product;

[0052] (6) the absorbent separated from the gypsum slurry is transported to the rich-lean liquid heat exchanger by a rich liquid pump for heat exchange, and then enters the regeneration tower, water vapor at 100℃-102℃ is used to heat the absorbent, under the action of heating, the carbonate decomposes to desorb CO2, the desorbed CO2 enters the subsequent purification and liquefaction process, the absorbent is changed from rich liquid to lean liquid, and thus the regeneration is completed, the regenerated absorbent returns to the circulating tank, and fresh lime slurry is added, so that the flue gas desulfurization and decarburization can be continuously performed.

[0053] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for preparing a flue gas desulfurization and decarbonization absorbent, comprising the following steps: Step 1: Prepare a Ca(OH)2 slurry with a concentration of 10-15%wt by mixing lime and water, which will be used as absorbent 1; Step 2: Mix the base solvent, active amine, water, corrosion inhibitor, and antioxidant in a mass ratio of 3:1:6:0.015:0.005 to obtain absorbent 2, wherein the base solvent is hydroxyethyl ethylenediamine (AEEA), the active amine is piperazine (PZ), the antioxidant is acetaldehyde oxime (AAO), and the corrosion inhibitor is a mixed solution of sodium molybdate and zinc acetate, with a mass ratio of sodium molybdate to zinc acetate of 4:

1. Step 3: Prepare a mixed solution by mixing absorbent 1 and absorbent 2 at a volume ratio of 1:10-1:20, and adjust the pH to 11 using an acid-base buffer solution to obtain the finished product.

2. The preparation method of the flue gas desulfurization and decarbonization absorbent according to claim 1, characterized in that... In step 3, if the pH of the mixed solution is <11, a saturated Ca(OH)2 solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also act as an SO2 absorbent; if the pH of the mixed solution is >11, an acetic acid (HAC) solution is selected as the acid-base buffer solution, which can adjust the pH to 11 and also react with Ca(OH)2 to generate calcium acetate, which can act as a CO2 absorbent.

3. A flue gas desulfurization and decarbonization absorbent, characterized in that, Prepared by the method described in claim 1 or 2.

4. A method for applying the flue gas desulfurization and decarbonization absorbent as described in claim 3, comprising the following steps: Step 1: The flue gas desulfurization and decarbonization absorbent is loaded into the circulation tank. The flue gas desulfurization and decarbonization absorbent is pumped to the top of the tower and sprayed evenly. It comes into countercurrent contact with the flue gas entering from the bottom of the tower. The Ca(OH)2 in the flue gas desulfurization and decarbonization absorbent reacts with SO2 to form CaSO3. The AEEA and PZ in the absorbent react with CO2 to form carbonates. The purified flue gas is discharged from the chimney after demisting and reheating. Step 2: The absorbed liquid after absorption is returned to the oxidation tank at the bottom of the tower. Under the condition of forced air, CaSO3 is oxidized to CaSO4, and then crystallized into gypsum CaSO4·2H2O. After the gypsum slurry is separated from the absorbed liquid, it is dehydrated and then further processed to complete the separation of desulfurization products. Step 3: The absorbent liquid separated from the gypsum slurry is pumped to the rich liquid heat exchanger for heat exchange, and then enters the regeneration tower. Under heating, the carbonates decompose and CO2 is desorbed. The desorbed CO2 enters the subsequent purification and liquefaction process. The absorbent is transformed from rich liquid to lean liquid, thus completing the regeneration. The regenerated absorbent returns to the circulation tank. Fresh lime slurry is added, and flue gas desulfurization and decarbonization can continue.

5. The application method of the flue gas desulfurization and decarbonization absorbent according to claim 4, characterized in that: In step 1, the SO2 concentration in the flue gas is 4000 ppm, the CO2 concentration is 12%, and the liquid / gas ratio is 4.7 L / m³. 3 The gas velocity is 3.0 m / s.

6. The application method of the flue gas desulfurization and decarbonization absorbent according to claim 4, characterized in that: In step 2, the oxidation air is blown into the oxidation tank using a Roots blower at a pressure of 5 x 10⁻⁶. 4 To ensure sufficient contact between the CaSO3 slurry and air, several agitators are arranged in the tank to keep the slurry in a flowing state. Oxidation air is arranged near the agitators through nozzles to optimize the airflow distribution. The residence time of the absorbent in the oxidation tank is 4 to 8 minutes.

7. The application method of the flue gas desulfurization and decarbonization absorbent according to claim 4, characterized in that... In step 3, the heating medium for absorbent regeneration is steam, and the temperature is 100℃-102℃.

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