Modified carbon capture solvent and preparation method thereof

Abstract

The invention relates to the technical field of carbon capture, and discloses a modified carbon capture solvent and a preparation method thereof.The modified carbon capture solvent is prepared from, by mass, 40-55 parts of multi-component organic alcohol amine, 0.1-0.3 part of antioxidant, 0.05-0.5 part of chloride ion capture agent, 0.05-0.2 part of corrosion inhibitor, 0.05-0.1 part of defoaming agent and demineralized water, and the multi-component organic alcohol amine is prepared from 25-30 parts of main absorbent and 15-25 parts of auxiliary modifier. The absorption performance of the modified carbon capture solvent is improved, the oxidative degradation is reduced, the corrosivity is weakened, the foaming tendency is reduced, the operation efficiency and the safety coefficient of a carbon capture device are comprehensively improved, and the application problem of a current coal-fired flue gas chemical absorption method carbon capture technology is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and particularly relates to a modified carbon capture solvent and a preparation method thereof. Background Art

[0002] The greenhouse effect is an environmental problem faced globally, and CO 2 as one of the greenhouse gases is receiving increasing attention. The carbon capture technology by chemical absorption has advantages such as fast absorption rate, good removal effect, and strong process adaptability for flue gas with large volume flow and low CO 2 concentration, and it is a post-combustion carbon capture technology with commercial promotion value.

[0003] The carbon capture solvent is the core of the chemical absorption method. Since organic alkanolamines contain at least one amino group in their molecular structures, their aqueous solutions are alkaline and can react with acidic gases (CO 2 , SO 2 etc.) in flue gas, and the acidic gases can be released again after heating. They are currently the mainstream carbon capture solvents for the chemical absorption method. Among them, N-methyldiethanolamine (MDEA) belongs to tertiary amines. Due to the absence of active H atoms in its molecular structure, compared with monoethanolamine (MEA), it has advantages such as good chemical stability, low corrosion, and low regeneration heat consumption, and has been widely used in the desulfurization and decarbonization of natural gas and syngas. Now it is gradually being promoted to the field of carbon capture from coal-fired flue gas. However, the N-methyldiethanolamine (MDEA) carbon capture solvent often shows slow absorption rate and fast solvent degradation under the conditions of coal-fired flue gas, and the absorption performance and solvent quality can be effectively improved by modifying the carbon capture solvent. Therefore, developing a modified carbon capture solvent suitable for the field of carbon capture from coal-fired flue gas is an effective measure to solve the current problems.

[0004] At present, the modification of the N-methyldiethanolamine (MDEA) carbon capture solvent for the field of carbon capture from coal-fired flue gas mainly focuses on improving the absorption rate. By replacing part of the tertiary amine (MDEA) with organic amines (MEA, DEA, AMP, DEEA, etc.) with relatively fast reaction rates with CO 2 to form a mixed amine carbon capture solvent with tertiary amine as the main absorbent and primary / secondary amine as the auxiliary absorbent / modifier, the absorption rate of the solvent is effectively improved. However, the oxidation, volatility, and corrosion of the modified carbon capture solvent may be aggravated, and problems such as solvent oxidative degradation and equipment corrosion will affect the operation of the system. In addition, some modifications of carbon capture solvents are based on adding auxiliaries such as antioxidants, corrosion inhibitors, and defoamers to the mixed amine solvent, which can achieve certain modification effects. However, the types and addition ratios of additives are based on the operation experience in the desulfurization and decarbonization fields of natural gas and syngas, and lack pertinence for the modification of carbon capture solvents based on the characteristics of coal-fired flue gas. Summary of the Invention

[0005] The present invention aims to provide a modified carbon capture solvent and a preparation method thereof to solve the problems of unsatisfactory absorption performance and pipeline corrosion existing in the carbon capture solvents in the prior art.

[0006] To achieve the above object, the present invention adopts the following technical solution: A modified carbon capture solvent, in parts by mass, includes 40-55 parts of multi-component organic alkanolamine, 0.1-0.3 parts of antioxidant, 0.05-0.5 parts of chloride ion scavenger, 0.05-0.2 parts of corrosion inhibitor, 0.05-0.1 parts of defoamer, and demineralized water. The multi-component organic alkanolamine includes 25-30 parts of main absorbent and 15-25 parts of auxiliary modifier.

[0007] Preferably, as an improvement, the modified carbon capture solvent includes 25%-30% of main absorbent, 15%-25% of auxiliary modifier, 0.1%-0.3% of antioxidant, 0.05%-0.5% of chloride ion scavenger, 0.05%-0.2% of corrosion inhibitor, 0.05%-0.1% of defoamer, and the balance is demineralized water.

[0008] Preferably, as an improvement, the main absorbent is N-methyldiethanolamine, and the auxiliary modifier is at least one of ethanolamine, diethanolamine, hydroxyethyl ethylenediamine, N-methyl-1,3-propanediamine, and 2-amino-2-methyl-1-propanol.

[0009] Preferably, as an improvement, the antioxidant is at least one of potassium chromate, potassium dichromate, sodium tartrate, and sodium metavanadate.

[0010] Preferably, as an improvement, the chloride ion scavenger is at least one of amino trimethylene phosphonic acid chelating agent, calcium nitrate, and aluminum sulfate.

[0011] Preferably, as an improvement, the corrosion inhibitor is at least one of sodium nitrite, sodium molybdate, zinc dihydrogen phosphate, and sodium tripolyphosphate.

[0012] Preferably, as an improvement, the defoamer is at least one of polydimethylsiloxane and polyether-modified silicone.

[0013] Preferably, as an improvement, a preparation method of a modified carbon capture solvent includes the following steps:

[0014] Step 1: Dissolve the main absorbent and the auxiliary modifier in demineralized water, and stir and mix to obtain a multi-component organic alkanolamine solvent;

[0015] Step 2: Add an antioxidant, a chloride ion scavenger, a corrosion inhibitor, and a defoamer to the multi-component organic alkanolamine solvent respectively, and stir and mix to obtain a modified carbon capture solvent.

[0016] Preferably, as an improvement, an application of a modified carbon capture solvent. During the use of the modified carbon capture solvent, the chelate formed by the chloride ion capturer and chloride ions is removed by the solvent purification equipment of the carbon capture system.

[0017] The principle and advantages of this solution are as follows: In practical applications, in this technical solution, aiming at the problems often occurring in the application of N-methyl diethanolamine (MDEA) carbon capture solvent in the field of coal-fired flue gas carbon capture, such as the decrease in decarbonization efficiency, corrosion of equipment pipelines, and foaming of the solution, the formulation and process of the carbon capture solvent are upgraded as a whole. During the R & D stage, the inventor considered the particularity of the nature of coal-fired flue gas itself. Different from the gas conditions of high-pressure gas sources such as natural gas and syngas, the parameters of coal-fired flue gas are more complex and it belongs to an atmospheric pressure gas source. And the reaction kinetic parameters of the carbon capture solvent with CO 2 under atmospheric pressure are weaker than those under high pressure, and the reaction rate is generally small. Based on this, this solution is based on the main absorbent N-methyl diethanolamine (MDEA), and several auxiliary modifiers are added to form a multi-component organic alkanolamine system. The oxygen content in coal-fired flue gas is relatively high, which greatly increases the risk of oxidative degradation of the carbon capture solvent. Through the composition optimization of the multi-component organic alkanolamine system and the cooperation with antioxidants, this solution can improve the antioxidant property of the solvent and reduce the solvent consumption. In addition, considering that coal-fired flue gas will carry a certain amount of chloride ions, which increases the corrosion tendency of the carbon capture device, and the carbon capture solvent is prone to generate stable salt ions such as formate, acetate, and oxalate after degradation, which have strong corrosiveness, this solution introduces a chloride ion capturer and a corrosion inhibitor into the carbon capture solvent. In addition, by compounding an antifoaming agent in the carbon capture solvent, the problem of solvent foaming caused by high dust particle concentration in coal-fired flue gas can be solved.

[0018] In summary, through the overall optimization of the carbon capture solvent, this solution improves the absorption performance, reduces oxidative degradation, weakens corrosiveness, and decreases the foaming tendency of the modified carbon capture solvent, comprehensively improving the operation efficiency and safety factor of the carbon capture device, and effectively solving the application problems of the current coal-fired flue gas chemical absorption method carbon capture technology. Detailed implementation methods

[0019] The following is a further detailed description through specific implementation methods, but the implementation methods of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following implementation methods are conventional means well-known to those skilled in the art; the experimental methods used are all conventional methods; the materials, reagents, etc. used can all be obtained from commercial channels.

[0020] General description of the solution:

[0021] A modified carbon capture solvent, comprising 40-55 parts of multi-component organic alkanolamine, 0.1-0.3 parts of antioxidant, 0.05-0.5 parts of chloride ion scavenger, 0.05-0.2 parts of corrosion inhibitor, 0.05-0.1 parts of defoamer and demineralized water, wherein the multi-component organic alkanolamine comprises 25-30 parts of main absorbent and 15-25 parts of auxiliary modifier.

[0022] More specifically: A modified carbon capture solvent, comprising 25%-30% of main absorbent, 15%-25% of auxiliary modifier, 0.1%-0.3% of antioxidant, 0.05%-0.5% of chloride ion scavenger, 0.05%-0.2% of corrosion inhibitor, 0.05%-0.1% of defoamer, and the balance being demineralized water.

[0023] Among them, the main absorbent is N-methyldiethanolamine (MDEA).

[0024] The auxiliary modifier is at least one of monoethanolamine (MEA), diethanolamine (DEA), aminoethylethanolamine (AEEA), N-methyl-1,3-propanediamine (MAPA), 2-amino-2-methyl-1-propanol (AMP).

[0025] The antioxidant is at least one of potassium chromate, potassium dichromate, sodium tartrate, sodium metavanadate.

[0026] The chloride ion scavenger is at least one of amino trimethylene phosphonic acid chelating agent, calcium nitrate, aluminum sulfate.

[0027] The corrosion inhibitor is at least one of sodium nitrite, sodium molybdate, zinc dihydrogen phosphate, sodium tripolyphosphate.

[0028] The defoamer is at least one of polydimethylsiloxane, polyether modified silicone.

[0029] A preparation method of a modified carbon capture solvent, comprising the following steps:

[0030] Step 1: Dissolve the main absorbent and the auxiliary modifier in demineralized water, stir well and mix evenly to obtain a multi-component organic alkanolamine solvent;

[0031] Step 2: Add an antioxidant, a chloride ion scavenger, a corrosion inhibitor and a defoamer to the multi-component organic alkanolamine solvent respectively, stir well and mix evenly to complete the preparation of a modified carbon capture solvent.

[0032] During the use of the modified carbon capture solvent, the consumption rates of the multi-component organic alkanolamine are different. GC-MS is used to detect and analyze the real-time proportion of each component, and the dosage is optimized to ensure that the modified carbon capture solvent always has good absorption-regeneration performance.

[0033] During the use of the modified carbon capture solvent, the chelate formed by the chloride ion capturer and chloride ions is removed through the solvent purification equipment of the carbon capture system to avoid the influence of chloride ions on the system.

[0034] Experimental Example 1 Absorption Performance Test

[0035] Experimental Raw Materials: Prepare the following five carbon capture solvents:

[0036] (1) 50% MDEA Solvent: The mass ratio of MDEA is 50.0%, and the rest is demineralized water;

[0037] (2) 1# Modified Solvent: The mass ratio of MDEA is 30.0%, the mass ratio of ethylenediamine (EDA) is 20.0%, and the rest is demineralized water;

[0038] (3) 2# Modified Solvent: The mass ratio of MDEA is 30.0%, the mass ratio of MEA is 15.0%, the mass ratio of AMP is 5.0%, and the rest is demineralized water;

[0039] (4) 3# Modified Solvent: The mass ratio of MDEA is 28.0%, the mass ratio of MAPA is 14.5%, the mass ratio of DEA is 7.5%, and the rest is demineralized water;

[0040] (5) 4# Modified Solvent: The mass ratio of MDEA is 26.0%, the mass ratio of AEEA is 16.0%, the mass ratio of AMP is 8.0%, and the rest is demineralized water.

[0041] The preparation processes of the above five groups of carbon capture solvents are the same as those in the general description part of the scheme. Carry out the CO 2 absorption-desorption performance experiments on the carbon capture solvents prepared in the above five groups of examples. The CO 2 absorption load, desorption load, and net load of the solvents are measured under the pressure conditions of normal pressure 0.1 MPa and high pressure 0.6 MPa respectively. The CO 2 load is measured by the constant volume method.

[0042] Among them, the absorption load can quantitatively characterize the absorption rate of the carbon capture solvent for CO 2 . The larger the absorption load, the faster the absorption rate of the solvent for CO 2 , and the better the absorption performance.

[0043] The desorption load can reflect the desorption effect of the carbon capture solvent. The smaller the desorption load, the more complete the desorption of the solvent for CO 2 .

[0044] The net load is the difference between the absorption load and the desorption load of the carbon capture solvent, and it is an important index for investigating the absorption-desorption performance of the carbon capture solvent. Generally, the larger the net load, the better the absorption-desorption performance of the carbon capture solvent, and the corresponding unit CO2 The lower the capture energy consumption.

[0045] The test results are shown in Table 1: The results show that under the condition of normal pressure 0.1 MPa, 50% MDEA solvent is used as the experimental control example, and its CO 2 Absorption loading is 0.25 mol / mol, and net loading is 0.16 mol / mol.

[0046] (1) The absorption loading of the 1# modified solvent is 0.29 mol / mol, which is 16.0% higher than that of the control example; the net loading is 0.15 mol / mol, which is 6.3% lower than that of the control example.

[0047] (2) The absorption loading of the 2# modified solvent is 0.39 mol / mol, which is 56.0% higher than that of the control example; the net loading is 0.26 mol / mol, which is 62.5% higher than that of the control example.

[0048] (3) The absorption loading of the 3# modified solvent is 0.41 mol / mol, which is 64.0% higher than that of the control example; the net loading is 0.25 mol / mol, which is 56.3% higher than that of the control example.

[0049] (4) The absorption loading of the 4# modified solvent is 0.42 mol / mol, which is 68.0% higher than that of the control example; the net loading is 0.25 mol / mol, which is 50.0% higher than that of the control example.

[0050] Under the condition of high pressure 0.6 MPa, the CO of 50% MDEA solvent 2 Absorption loading is 0.35 mol / mol, and net loading is 0.21 mol / mol.

[0051] (5) The absorption loading of the 1# modified solvent is 0.39 mol / mol, which is 11.4% higher than that of the control example; the net loading is 0.19 mol / mol, which is 9.5% lower than that of the control example.

[0052] (6) The absorption loading of the 2# modified solvent is 0.47 mol / mol, which is 34.4% higher than that of the control example; the net loading is 0.28 mol / mol, which is 33.3% higher than that of the control example.

[0053] (7) The absorption loading of the 3# modified solvent is 0.48 mol / mol, which is 37.1 higher than that of the control example; the net loading is 0.30 mol / mol, which is 42.9% higher than that of the control example.

[0054] (8) The absorption loading of the 4# modified solvent is 0.50 mol / mol, which is 42.9% higher than that of the control example; the net loading is 0.29 mol / mol, which is 38.1% higher than that of the control example.

[0055] It can be found that compared with the CO absorption loading and net loading of the 50% MDEA solvent, although the absorption loading of the 1# modified solvent has increased, the net loading has decreased, indicating that the auxiliary modifier ethylenediamine (EDA) has no improvement effect on the absorption-desorption performance; the absorption loading and net loading of the 2# - 4# modified solvents have both increased significantly, indicating that the modification method provided by this patent can improve the absorption rate and desorption effect of the carbon capture solvent on CO. 2 2

[0056] Table 1 CO loadings of five carbon capture solvents at different pressures 2 loading

[0057]

[0058] Experimental Example 2 Antioxidant and Corrosion Resistance Tests

[0059] Experimental Raw Materials: Prepare the following four carbon capture solvents:

[0060] (1) 50% MDEA Solvent: The mass ratio of MDEA is 50.0%, and the rest is demineralized water.

[0061] (2) 5# Modified Solvent: The mass ratio of MDEA is 30.0%, the mass ratio of MEA is 15.0%, the mass ratio of AMP is 5.0%, and the rest is demineralized water.

[0062] (3) 6# Modified Solvent: The mass ratio of MDEA is 30.0%, the mass ratio of MEA is 15.0%, the mass ratio of AMP is 5.0%, the mass ratio of sodium tartrate is 0.15%, the mass ratio of zinc dihydrogen phosphate is 0.10%, and the rest is demineralized water.

[0063] (4) 7# Modified Solvent: The mass ratio of MDEA is 30.0%, the mass ratio of MEA is 15.0%, the mass ratio of AMP is 5.0%, the mass ratio of sodium tartrate is 0.25%, the mass ratio of zinc dihydrogen phosphate is 0.20%, and the rest is demineralized water.

[0064] The preparation processes of the above four groups of carbon capture solvents are the same as those in the general description part of the scheme. In the test gas source of 50% O 2 / 50% CO 2 ​​Under the conditions of an absorption temperature of 45 °C, a desorption temperature of 110 °C, and multiple absorption-desorption cycles, the oxidative degradation and the contents of corrosion product ions of four carbon capture solvents were detected to characterize the antioxidant and corrosion resistance properties of the solvents, thereby obtaining the modification effects of antioxidants and corrosion inhibitors on carbon capture solvents. Among them, the oxidative degradation and corrosion products in the solvent were detected using an ion chromatograph. The larger the ion content detection result, the more severe the oxidative degradation of the solvent and the corrosion of the equipment.

[0065] The main degradation and corrosion product ions in the carbon capture solvent were detected using an ion chromatograph. Among them, formate, acetate, and oxalate are the main degradation product ions of the solvent, and iron ions are the corrosion product ions. The results are shown in Table 2. The results show that, taking the 50% MDEA solvent as the experimental control example, the contents of degradation product ions and corrosion product ions of the modified solvents No. 5-7 are higher than those of the control example, indicating that although the modification of the carbon capture solvent can improve the absorption performance, it will cause a decrease in antioxidant performance and an increase in corrosion.

[0066] In addition, compared with the modified solvents No. 6 and 7, the antioxidant (sodium tartrate) and corrosion inhibitor (zinc dihydrogen phosphate) were not added to the modified solvent No. 5. The results show that the main degradation product ions in the solvent: formate 592 mg / L, acetate 318 mg / L, oxalate 702 mg / L, and the corrosion product ion: iron ion 27 mg / L all showed relatively high contents. Due to the addition of sodium tartrate and zinc dihydrogen phosphate in the modified solvents No. 6 and 7, the contents of the main degradation product ions and corrosion product ions were reduced by more than 50%. Moreover, the modification effects of different addition mass ratios were also different, indicating that antioxidants and corrosion inhibitors in the modified solvent can play an important role in effectively inhibiting the oxidative degradation of the solvent and the corrosion of the equipment.

[0067] Table 2 Contents of main oxidative degradation and corrosion product ions of four carbon capture solvents

[0068]

[0069] Experimental Example 3 Test on the removal effect of chloride ions

[0070] Experimental raw materials, prepare the following five carbon capture solvents:

[0071] (1) Modified solvent No. 8: mass ratio of MDEA 30.0%, mass ratio of DEA 15.0%, mass ratio of AMP 5.0%, and the rest is demineralized water;

[0072] (2) Modified solvent No. 9: mass ratio of MDEA 30.0%, mass ratio of MEA 15.0%, mass ratio of AMP 5.0%, mass ratio of chloride ion capturer (aminotrimethylene phosphonic acid chelating agent) 0.3%, and the rest is demineralized water;

[0073] (3) Modified solvent: 30.0% by mass of MDEA, 15.0% by mass of MEA, 5.0% by mass of AMP, 0.3% by mass of chloride ion scavenger (calcium nitrate), and the rest is demineralized water;

[0074] (4) Modified solvent: 30.0% by mass of MDEA, 15.0% by mass of MEA, 5.0% by mass of AMP, 0.3% by mass of chloride ion scavenger (aluminum sulfate), and the rest is demineralized water;

[0075] (5) Modified solvent: 30.0% by mass of MDEA, 15.0% by mass of MEA, 5.0% by mass of AMP, 0.3% by mass of chloride ion scavenger (sodium thiosulfate), and the rest is demineralized water;

[0076] The preparation processes of the above five groups of carbon capture solvents are the same as those in the general description part of the scheme. Under the test conditions of 50% O 2 / 50% CO 2 , gas flow rate of 2 L / min, and gas chloride ion content of 3 mg / L, after absorption - desorption multi - cycle for 1 h, 5 h, and 10 h, the chloride ion contents of the five carbon capture solvents are detected, and the removal effect of the chloride ion scavenger on the chloride ions in the carbon capture solvent is characterized. Among them, the chloride ions in the solvent are detected by an ion chromatograph. The smaller the detected result of the chloride ion content, the better the effect of the chloride ion scavenger in the carbon capture solvent.

[0077] The test results are shown in Table 3. In this experiment, the 8# modified solvent is used as the experimental control example, in which no chloride ion scavenger is added, while 0.3% chloride ion scavengers are added to the 9# - 12# modified solvents, which are amino - trimethylene - phosphonic acid chelating agent, calcium nitrate, aluminum sulfate, and sodium thiosulfate respectively. The test results show that the chloride ion content level in the 8# modified solvent is relatively high, reaching 904 mg / L after continuous operation for 10 h.

[0078] Under the same operating conditions, the chloride ion content corresponding to the 9# modified solvent is 374 mg / L, a year - on - year decrease of 58.6%;

[0079] The chloride ion content corresponding to the 10# modified solvent is 463 mg / L, a year - on - year decrease of 48.8%;

[0080] The chloride ion content corresponding to the 11# modified solvent is 311 mg / L, a year - on - year decrease of 65.5%.

[0081] The chloride ion content corresponding to the 12# modified solvent is 798 mg / L, a year - on - year decrease of 11.7%.

[0082] Compared with the 8# modified solvent, the chloride ion content in the 9#-11# modified solvents is significantly reduced, indicating that the amino trimethylene phosphonic acid chelating agent, calcium nitrate, and aluminum sulfate chloride scavengers can effectively capture chloride ions to achieve the purpose of reducing the chloride ion content in the carbon capture solvent. However, the chloride ion content in the 12# modified solvent still remains at a relatively high level, indicating that sodium thiosulfate has a poor effect as a chloride ion scavenger and is not recommended for use.

[0083] Table 3 Chloride ion content corresponding to five carbon capture solvents

[0084]

[0085] Experimental Example 4 Foaming tendency test

[0086] Experimental raw materials, prepare the following three carbon capture solvents:

[0087] (1) 13# modified solvent: mass ratio of MDEA 30.0%, mass ratio of MAPA 17.0%, mass ratio of AMP 8.0%, mass ratio of sodium tartrate 0.20%, mass ratio of zinc dihydrogen phosphate 0.10%, and the rest is demineralized water;

[0088] (2) 14# modified solvent: mass ratio of MDEA 30.0%, mass ratio of MAPA 17.0%, mass ratio of AMP 8.0%, mass ratio of sodium tartrate 0.20%, mass ratio of zinc dihydrogen phosphate 0.10%, mass ratio of polyether modified silicone 0.05%, and the rest is demineralized water;

[0089] (3) 15# modified solvent: mass ratio of MDEA 30.0%, mass ratio of MAPA 17.0%, mass ratio of AMP 8.0%, mass ratio of sodium tartrate 0.20%, mass ratio of zinc dihydrogen phosphate 0.10%, mass ratio of polyether modified silicone 0.10%, and the rest is demineralized water.

[0090] The preparation processes of the above three groups of carbon capture solvents are the same as those in the general description part of the scheme. Referring to the reference standard SY / T 6538-2016 "Formulation-Type Selective Desulfurization Solvent" for the above three groups of carbon capture solvents, use a foaming tube to measure the foaming height and defoaming time of the carbon capture solvent to judge the implementation effect of the defoamer. Among them, the foaming height is defined as the foam height of the carbon capture solvent in the foaming tube after 5 minutes of gas injection, and the defoaming time is defined as the time from the instant when gas injection stops to when the foam just dissipates from the lower liquid level. If the foaming height of the solvent is higher and the defoaming time is longer, it indicates that the foaming tendency of the solvent is greater.

[0091] The unmodified solvent without defoamer was used as the blank control example of Experimental Example 4. The results are shown in Table 4. The results show that 0.05% by mass of polyether-modified silicone was added to the 14# modified solvent, with a foaming height of 14 cm and a defoaming time of 42 s; 0.10% by mass of polyether-modified silicone was added to the 15# modified solvent, with a foaming height of 11 cm and a defoaming time of 31 s. It can be found that modification with a defoamer can significantly reduce the foaming height and defoaming time of the carbon capture solvent, reduce the foaming tendency of the solvent, and avoid many adverse effects on the system caused by solvent foaming.

[0092] Table 4 Foaming height and defoaming time of three modified solvents

[0093] Parameter 13# Modified Solvent 14# Modified Solvent 15# Modified Solvent Foaming Height (cm) 21 14 11 Defoaming Time (s) 78 42 31

[0094] Experimental Example 5 Operation test

[0095] Experimental raw materials, and the following three carbon capture solvents were prepared:

[0096] (1) 50% MDEA solvent: 50.0% by mass of MDEA, and the rest is demineralized water;

[0097] (2) 16# modified solvent: 30.0% by mass of MDEA, 15.0% by mass of MAPA, 5.0% by mass of AMP, and the rest is demineralized water;

[0098] (3) 17# modified solvent: 30.0% by mass of MDEA, 15.0% by mass of MAPA, 5.0% by mass of AMP, 0.20% by mass of sodium tartrate, 0.30% by mass of amino trimethylene phosphonic acid chelating agent, 0.10% by mass of zinc dihydrogen phosphate, 0.10% by mass of polyether-modified silicone, and the rest is demineralized water.

[0099] The preparation processes of the above three groups of carbon capture solvents are the same as those in the general description of the scheme. The above three groups of carbon capture solvents were tested on a pilot platform for carbon capture from ten thousand tons of coal-fired flue gas, and comprehensive performance results such as the absorption-regeneration effect, antioxidant degradation, corrosion resistance, and foam inhibition of the modified carbon capture solvents were obtained. Among them, the main test conditions of the carbon capture pilot platform are shown in Tables 5-6 below.

[0100] Table 5 Inlet flue gas parameters of the pilot platform for carbon capture from ten thousand tons of coal-fired flue gas

[0101] Item Parameter <![CDATA[Flue gas volume (Nm 3 / h)]]> 7900 <![CDATA[CO 2 (%)]]> 13％ <![CDATA[O 2 (%)]]> 8％ <![CDATA[N 2 (%)]]> 70％ <![CDATA[H 2 O(%)]]> 9％ <![CDATA[Dust concentration (mg / Nm 3 )]]> <![CDATA[3mg / Nm 3 > <![CDATA[SO 2 Concentration (mg / Nm 3 )]]> <![CDATA[10mg / Nm 3 > <![CDATA[NOx concentration (mg / Nm 3 )]]> <![CDATA[24mg / Nm 3 > <![CDATA[Chloride ion concentration (mg / Nm 3 )]]> <![CDATA[0.2mg / Nm 3 > Temperature (°C) 40℃ Pressure (kPa) 10 kPa

[0102] Table 6 Operating parameters of the pilot platform for carbon capture from ten thousand tons of coal-fired flue gas

[0103] Item Parameter Carbon Capture Solvent Quantity (t) 35t Total Amine Concentration (%) 50％ Absorption Temperature (°C) 39℃ Regeneration Temperature (°C) 110℃ <![CDATA[Solution circulation rate (m 3 / h)]]> <![CDATA[50m 3 / h]]> Operation Duration (d) 30

[0104] In this experimental example, the 50% MDEA solvent was used as a blank control example. The test results are shown in Table 7, and the results indicate that: for the No. 16 modified solvent, only multi-component organic alkanolamines were added, and the net loading increased from 0.26 mol / mol to 0.39 mol / mol, but the corresponding oxidative degradation rate was 0.92 kg / tCO 2 and the corrosivity (iron ion content was 79 mg / L) both increased significantly, and there were also unfavorable phenomena such as a relatively high chloride ion content and foaming in the solvent at the same time.

[0105] The No. 17 modified solvent was prepared according to the ratio provided by this patent, and a high net loading of 0.40 mol / mol was obtained during operation; the oxidative degradation rate was 0.76 kg / tCO 2 and the iron ion content of 32 mg / L was much lower than that of the No. 16 modified solvent, indicating that the antioxidants and corrosion inhibitors in the modified solvent could play their roles; in addition, compared with the 50% MDEA solvent and the No. 16 modified solvent, the chloride ion content of the No. 17 modified solvent was only 428 mg / L, indicating that the chloride ion scavenger effectively reduced the chloride ion content in the solvent. At the same time, the No. 17 modified solvent did not show a foaming tendency.

[0106] Table 7 Comprehensive performance data of carbon capture solvents

[0107]

[0108] The results indicate that a modified carbon capture solvent provided by this patent shows excellent comprehensive performances such as a high net loading, a slow oxidative degradation rate, a low corrosivity, a high chloride ion removal rate, and a weak foaming tendency during the application process of coal-fired flue gas carbon capture engineering, meeting the modification requirements of a carbon capture solvent.

[0109] The above are only examples of the present invention, and specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can still be made, and these should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application should be subject to the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. A modified carbon capture solvent, characterized in that: Calculated by mass, it includes 40-55 parts of multi-component organic alcohol amine, 0.1-0.3 parts of antioxidant, 0.05-0.5 parts of chloride ion scavenger, 0.05-0.2 parts of corrosion inhibitor, 0.05-0.1 parts of defoaming agent and desalted water, and the multi-component organic alcohol amine includes 25-30 parts of main absorbent and 15-25 parts of auxiliary modifier.

2. A modified carbon capture solvent according to claim 1, characterized in that: The main absorbent is N-methyldiethanolamine, and the auxiliary modifier is at least one of ethanolamine, diethanolamine, hydroxyethylethylenediamine, N-methyl-1,3-propylenediamine, and 2-amino-2-methyl-1-propanol.

3. The modified carbon capture solvent according to claim 1, characterized in that: The antioxidant is at least one of potassium chromate, potassium dichromate, sodium tartrate and sodium metavanadate.

4. The modified carbon capture solvent according to claim 1, characterized in that: The chloride ion scavenger is at least one of aminotrimethylenephosphonic acid chelating agent, calcium nitrate and aluminum sulfate.

5. The modified carbon capture solvent according to claim 1, characterized in that: The corrosion inhibitor is at least one of sodium nitrite, sodium molybdate, zinc dihydrogen phosphate and sodium tripolyphosphate.

6. A method for preparing a modified carbon capture solvent according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, dissolving the main absorbent and the auxiliary modifier in deionized water, stirring and mixing, to obtain a multi-component organic alcohol amine solvent; Step 2: respectively add an antioxidant, a chloride ion scavenger, a corrosion inhibitor and a defoamer into a multi-component organic alcohol amine solvent, stir and mix, and obtain a modified carbon capture solvent.

7. The use of a modified carbon capture solvent according to any one of claims 1 to 5, characterized in that: During the use of the modified carbon capture solvent, the chelate formed by the chloride ion capture agent and the chloride ion is removed by the solvent purification equipment of the carbon capture system.

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