A defoaming composition and use thereof

Abstract

The application provides a defoaming composition and application thereof. The defoaming composition comprises a polyether-modified organosilicon surfactant, an alkylsiloxane surfactant, a Tween surfactant, a low-carbon alcohol and water, has good defoaming and foam suppressing performance, and has low cost. After being diluted and added into amine desulfurization liquid (namely MDEA solution), the defoaming composition can make the foam generated in the MDEA solution disappear quickly, control the foaming height of the MDEA solution within 50 cm within 10 s, is beneficial to the stable circulation of the amine liquid in the amine liquid absorption tower, and cannot seriously foam to affect the amine liquid circulation amount and then affect the sulfide absorption efficiency.

Description

Technical Field

[0001] This invention belongs to the field of defoaming technology for amine desulfurization liquid, and particularly relates to a defoaming composition and its application. Background Technology

[0002] Natural gas, as an important chemical raw material and a clean, convenient, and efficient high-quality fuel, has received widespread attention globally for its development and utilization. During the extraction process, natural gas often produces acidic gases such as H2S and CO2; therefore, natural gas must be purified before being transported abroad.

[0003] The most common method for natural gas purification and desulfurization is the chemical absorption method using alkanolamine solution. After absorbing acidic components from the natural gas, the alkanolamine solution is regenerated at high temperature and low pressure and returned to the absorption tower. During the recycling process, impurities such as solid particles, dust, oil, water, and gas field production additives contained in the upstream natural gas cannot be completely filtered and separated. Some impurities enter the solution circulation system, and the alkanolamine solution itself degrades under high temperature and aerobic conditions, leading to a gradual increase in impurities in the solution.

[0004] Currently, stable system operation is ensured by intermittently adding defoamers and enhancing solution filtration. With the continuous development of gas fields, especially the upstream and downstream mixed transportation, the composition of natural gas becomes more complex, and the content of hydrocarbon components and additives increases. This leads to frequent foaming of the downstream natural gas purification amine desulfurization liquid, requiring continuous addition of defoamers to the natural gas purification amine desulfurization liquid. However, the original imported antifoaming agents are expensive, increasing the cost of natural gas purification.

[0005] Therefore, in order to stabilize production and save costs, it is necessary to develop a defoamer that is cheaper and has better defoaming and foam-suppressing effects, explore its applicability in existing process equipment, study its compatibility with MDEA solution, and propose process operation optimization schemes to reduce the frequency of liquid interception in the desulfurization tower, reduce the probability of solution foaming, and ensure the safe and stable operation of the desulfurization system of the purification unit. Summary of the Invention

[0006] To address the problem of frequent foaming in natural gas purification amine desulfurization liquid, which necessitates the continuous addition of expensive imported antifoaming agents, thus increasing the cost of natural gas purification, this invention aims to provide a cheaper defoaming agent with better defoaming and foam-suppressing effects for defoaming in natural gas purification amine desulfurization liquid, thereby reducing the cost of natural gas purification.

[0007] To achieve the above objectives, one aspect of the present invention provides an antifoaming composition comprising a polyether-modified silicone surfactant, an alkylsiloxane surfactant, a Tween surfactant, a low alcohol, and water.

[0008] According to a specific embodiment of the present invention, the total mass of the defoaming composition is 100%, and the defoaming composition comprises 6-12 wt% of the polyether-modified silicone surfactant, 6-12 wt% of the alkylsiloxane surfactant, 0-1.5 wt% of the Tween surfactant, 0.1-1 wt% of the low alcohol and the balance being water.

[0009] According to a specific embodiment of the present invention, the total mass of the defoaming composition is 100%, and the defoaming composition comprises 6-12 wt% of the polyether-modified silicone surfactant, 6-10 wt% of the alkylsiloxane surfactant, 0.5-1 wt% of the Tween surfactant, 0.5-1 wt% of the low alcohol and the balance being water.

[0010] According to a specific embodiment of the present invention, the polyether-modified organosilicon surfactant includes at least one of polyether-modified polysiloxane, alkyl polyether siloxane, and fluoroalkyl polyether-modified siloxane.

[0011] According to a specific embodiment of the present invention, the alkylsiloxane surfactant is at least one selected from polydimethylsiloxane, ethoxy-modified trisiloxane, and tert-butyldimethylsiloxane acetaldehyde.

[0012] According to a specific embodiment of the present invention, the Tween-type surfactant includes Tween 20 and / or Tween 40.

[0013] According to a specific embodiment of the present invention, the low-carbon alcohol includes at least one of C2 to C4 alcohols.

[0014] The second aspect of the present invention provides the application of the defoaming composition according to the first aspect of the present invention in the defoaming of amine desulfurization liquid.

[0015] According to a specific embodiment of the present invention, the effective defoaming concentration of the defoaming composition is not less than 20%.

[0016] According to a specific embodiment of the present invention, the defoaming composition controls the foaming height of the amine desulfurization liquid to be no higher than 50 cm; and / or the defoaming time to be no longer than 10 s.

[0017] The beneficial effects of this invention are:

[0018] To address the problem of frequent foaming in amine-based desulfurization liquid during natural gas purification, which necessitates the continuous addition of expensive imported antifoaming agents and increases the cost of natural gas purification, this invention provides an defoaming composition and its application. The defoaming composition comprises a polyether-modified organosilicon surfactant, an alkylsiloxane surfactant, a Tween-type surfactant, a low-carbon alcohol, and water. The polyether-modified organosilicon surfactant exhibits good water solubility, and the alkylsiloxane surfactant has low surface tension. Combined with the Tween-type surfactant, low-carbon alcohol, and water, it possesses excellent defoaming and foam-suppressing properties. When diluted and added to the amine-based desulfurization liquid (i.e., MDEA solution), it rapidly eliminates foam generated in the MDEA solution, controlling the foam height to within 50 cm within 10 seconds. This promotes stable circulation of the amine solution in the amine absorption tower, preventing severe foaming that could affect the amine circulation volume and thus the sulfide absorption effect. Furthermore, the defoaming composition provided by this invention is significantly cheaper than expensive imported antifoaming agents, thus reducing the cost of natural gas purification. Detailed Implementation

[0019] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0020] The "effective defoaming concentration" referred to in this invention means: after further diluting the prepared defoaming composition with water to a certain concentration, it is added to the amine desulfurization liquid (i.e., MDEA solution) for defoaming and foam suppression; when the foam height of the amine desulfurization liquid is controlled to be no higher than 50 cm, the corresponding diluted concentration of the defoaming composition is the effective defoaming concentration. The diluted concentration of the defoaming composition is explained as follows: further diluting the prepared defoaming composition with water to obtain a diluted defoaming composition; taking the total mass of the diluted defoaming composition as 100%, where the mass percentage of the defoaming composition is A%, that is, the diluted concentration of the defoaming composition is A%. Obviously, when the mass of the defoaming composition is a constant value, the higher the mass of water added during the dilution process, the lower the diluted concentration A% of the defoaming composition.

[0021] Natural gas is an important chemical raw material and high-quality fuel. Its extraction process often generates acidic gases such as H2S and CO2, which need to be removed before the natural gas is exported. Currently, the commonly used method for natural gas purification and desulfurization is the amine solution chemical absorption method. After absorbing the acidic components from the natural gas, the amine solution undergoes high-temperature, low-pressure regeneration and is returned to the absorption tower for further absorption of acidic gases. In this method, the amine solution is recycled. During this recycling process, impurities such as solid particles, dust, oil, water, and gas field production additives contained in the upstream natural gas cannot be completely removed by filtration. Some of these impurities enter the amine solution recycling system, leading to a gradual increase in impurities within the solution. Furthermore, the amine solution itself degrades under high-temperature and aerobic conditions, further increasing impurities. As impurities increase, foaming problems become more prominent. The current solution is to continuously add expensive imported antifoaming agents to the natural gas purification and desulfurization amine solution, which significantly increases the cost of natural gas purification.

[0022] To stabilize production and save costs, this invention provides a defoamer that is more affordable and has good defoaming and foam-suppressing effects. It has good applicability to existing process equipment and good compatibility with existing amine solutions, namely MDEA solutions. Combined with the optimized process operation scheme, it can effectively reduce the frequency of liquid interception in the desulfurization tower, reduce the probability of solution foaming, ensure the safe and stable operation of the desulfurization system of the purification unit, and reduce the cost of natural gas purification.

[0023] The first aspect of this invention provides an antifoaming composition comprising a polyether-modified silicone surfactant, an alkylsiloxane surfactant, a Tween-type surfactant, a low-carbon alcohol, and water. In this antifoaming composition, the combination of the polyether-modified silicone surfactant, the alkylsiloxane surfactant, the Tween-type surfactant, and the low-carbon alcohol achieves good stability and a long-lasting defoaming and foam-suppressing effect.

[0024] In the defoaming composition, the proportion of various surfactants affects the stability and defoaming and foam-suppressing performance of the defoaming composition. To achieve better stability and defoaming and foam-suppressing performance, the present invention provides the following embodiments and preferred embodiments.

[0025] In one specific embodiment of the present invention, the total mass of the defoaming composition is 100%, the defoaming composition comprising 6-12 wt% of the polyether-modified silicone surfactant, 6-12 wt% of the alkylsiloxane surfactant, 0-1.5 wt% of the Tween surfactant, 0.1-1 wt% of the low alcohol and the balance being water.

[0026] In a preferred embodiment of the present invention, the total mass of the defoaming composition is 100%, the defoaming composition comprising 6-12 wt% of the polyether-modified silicone surfactant, 6-10 wt% of the alkylsiloxane surfactant, 0.5-1 wt% of the Tween surfactant, 0.5-1 wt% of the low alcohol and the balance being water.

[0027] In a preferred embodiment of the present invention, the total mass of the defoaming composition is 100%, and the defoaming composition comprises 12 wt% of the polyether-modified silicone surfactant, 6 wt% of the alkylsiloxane surfactant, 1 wt% of the Tween surfactant, 1 wt% of the low alcohol and the balance being water.

[0028] In a preferred embodiment of the present invention, the total mass of the defoaming composition is 100%, and the defoaming composition comprises 6 wt% of the polyether-modified silicone surfactant, 10 wt% of the alkylsiloxane surfactant, 0.5 wt% of the Tween surfactant, 0.5 wt% of the low alcohol and the balance being water.

[0029] In one specific embodiment of the present invention, the polyether-modified organosilicon surfactant includes at least one of polyether-modified polysiloxane, alkyl polyether siloxane, and fluoroalkyl polyether-modified siloxane.

[0030] In a preferred embodiment of the present invention, the alkyl polyether siloxane is dimethyl polyether siloxane.

[0031] In one specific embodiment of the present invention, the alkylsiloxane surfactant is at least one selected from polydimethylsiloxane, ethoxy-modified trisiloxane, and tert-butyldimethylsiloxane acetaldehyde.

[0032] In a preferred embodiment of the present invention, the alkylsiloxane surfactant is tert-butyldimethylsiloxane acetaldehyde.

[0033] In one specific embodiment of the present invention, the Tween-type surfactant includes Tween 20 and / or Tween 40.

[0034] In one specific embodiment of the present invention, the low-carbon alcohol includes at least one of C2 to C4 alcohols.

[0035] In one specific embodiment of the present invention, the lower alcohol is any one or more of isopropanol, propanol and butanol.

[0036] A second aspect of the present invention provides the application of the defoaming composition according to the first aspect of the present invention in the defoaming of amine desulfurization liquid.

[0037] In one specific embodiment of the present invention, the amine desulfurization liquid is an MDEA (i.e., N-methyldiethanolamine) solution.

[0038] In one specific embodiment of the present invention, the defoaming composition is diluted with water and then added to the amine desulfurization liquid to defoam the amine desulfurization liquid.

[0039] In one specific embodiment of the present invention, the effective defoaming concentration of the defoaming composition is not less than 20%.

[0040] In one specific embodiment of the present invention, the defoaming composition controls the foaming height of the amine desulfurization liquid to be no higher than 50 cm; and / or the defoaming time to be no longer than 10 s.

[0041] The following provides several examples of formulating the defoaming composition, along with tests on the defoaming and foam-suppressing performance of the defoaming composition, to further illustrate the technical solution and the technical effects achieved by the present invention.

[0042] Preparation of defoaming compositions and testing of their defoaming and foam-suppressing properties

[0043] Example 1

[0044] The defoaming composition provided in this embodiment includes dimethyl polyether siloxane, tert-butyldimethylsiloxane acetaldehyde, Tween 20, isopropanol and water;

[0045] The total mass of the defoaming composition is 100%, of which dimethyl polyether siloxane accounts for 12 wt%, tert-butyldimethylsiloxane acetaldehyde accounts for 6 wt%, Tween 20 accounts for 1 wt%, isopropanol accounts for 1 wt%, and water accounts for 80 wt%.

[0046] The dimethyl polyether siloxane used in this embodiment was purchased from Wuhan Huaxiang Kejie Biotechnology Co., Ltd.

[0047] This embodiment also provides an exemplary method for preparing an antifoaming composition according to the above formulation:

[0048] Weigh 12g of dimethyl polyether siloxane, 6g of tert-butyldimethylsiloxane acetaldehyde, 1g of Tween 20, 1g of isopropanol and 80g of water, and stir until they are mixed evenly to obtain defoaming composition 1.

[0049] Test Example 1

[0050] According to the experimental procedure for determining foaming tendency in "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents", the defoaming ability of the defoaming composition 1 provided in Example 1 on MDEA solution was tested.

[0051] The MDEA concentration in the MDEA solution used in this test example is 45% (that is, the total mass of the MDEA solution is 100%, of which MDEA accounts for 45% by mass).

[0052] The specific testing steps are as follows:

[0053] (1) Take an appropriate amount of the defoaming composition 1 provided in Example 1, and add water to dilute the defoaming composition 1 while stirring to obtain the diluted defoaming composition 1; the total mass of the diluted defoaming composition 1 is 100%, of which the mass percentage of the defoaming composition 1 is 30%;

[0054] (2) Weigh 100 mL of 45% MDEA solution into the glass tube of the foaming evaluator and heat the glass tube in a water bath at 45°C until the temperature of the MDEA solution in the glass tube is the same as the temperature of the water bath. Then weigh 5 mg of the diluted defoaming composition 1 prepared in (1) and add it into the glass tube. Then, introduce nitrogen gas into the test solution (i.e., the mixture of MDEA solution and diluted defoaming composition 1) in the glass tube at a rate of 250 mL / min for 2 min.

[0055] (3) After the nitrogen flow is completed, turn off the nitrogen flow and record the height of the foam generated by the test liquid in the glass tube, and record the time it takes for the foam to completely disappear (i.e., the defoaming time).

[0056] The test results are shown in Table 1.

[0057] Table 1. Defoaming performance of defoaming composition 1

[0058]

[0059] As shown in Table 1, the defoaming composition 1 provided in Example 1, after being diluted to a concentration of 30% and added to a 45% MDEA solution, achieved a good defoaming and foam suppression effect: after nitrogen gas was introduced at a rate of 250 mL / min for 2 minutes, the foam height was only 30 mm and the defoaming time was only 5 seconds. This proves that the defoaming composition 1 provided in Example 1 can effectively defoam the MDEA solution, eliminating foam in a short time while controlling the foam height. This is beneficial to the stable circulation of amine liquid in the amine liquid absorption tower and avoids the problem of amine liquid foaming reducing the circulation volume and thus affecting the acid gas absorption effect of amine liquid circulation.

[0060] Example 2

[0061] The defoaming composition provided in this embodiment includes polyether-modified polysiloxane, tert-butyldimethylsiloxane acetaldehyde, Tween 40, propanol and water;

[0062] The total mass of the defoaming composition is 100%, of which polyether modified polysiloxane accounts for 12 wt%, tert-butyldimethylsiloxane acetaldehyde accounts for 6 wt%, Tween 40 accounts for 1 wt%, propanol accounts for 1 wt%, and water accounts for 80 wt%.

[0063] The polyether-modified polysiloxane used in this embodiment was purchased from Shandong Dayi Chemical Co., Ltd., product model DY-ET116.

[0064] This embodiment also provides an exemplary method for preparing an antifoaming composition according to the above formulation:

[0065] Weigh 12g of polyether-modified polysiloxane, 6g of tert-butyldimethylsiloxane acetaldehyde, 1g of Tween 40, 1g of propanol and 80g of water, and stir until they are mixed evenly to obtain defoaming composition 2.

[0066] Test Example 2

[0067] According to the experimental procedure for determining foaming tendency in "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents", the defoaming ability of the defoaming composition 2 provided in Example 2 on MDEA solution was tested.

[0068] The MDEA concentration in the MDEA solution used in this test example is 45% (that is, the total mass of the MDEA solution is 100%, of which MDEA accounts for 45% by mass).

[0069] The specific testing steps are as follows:

[0070] (1) Take an appropriate amount of the defoaming composition 2 provided in Example 2, and add water to dilute the defoaming composition 2 while stirring to obtain the diluted defoaming composition 2; the total mass of the diluted defoaming composition 2 is 100%, of which the mass percentage of the defoaming composition 2 is 30%;

[0071] (2) Weigh 100 mL of 45% MDEA solution into the glass tube of the foaming evaluator and heat the glass tube in a 45°C water bath until the temperature of the MDEA solution in the glass tube is the same as the temperature of the water bath. Then weigh 5 mg of the diluted defoaming composition 2 prepared in (1) and add it into the glass tube. Then, introduce nitrogen gas into the test solution (i.e., the mixture of MDEA solution and diluted defoaming composition 2) in the glass tube at a rate of 250 mL / min for 2 min.

[0072] (3) After the nitrogen flow is completed, turn off the nitrogen flow and record the height of the foam generated by the test liquid in the glass tube, and record the time it takes for the foam to completely disappear (i.e., the defoaming time).

[0073] The test results are shown in Table 2.

[0074] Table 2. Defoaming performance of defoaming composition 2

[0075]

[0076] As shown in Table 2, the defoaming composition 2 provided in Example 2, after being diluted to a concentration of 30% and added to a 45% MDEA solution, also achieved a better defoaming and foam suppression effect: after nitrogen was introduced at a rate of 250 mL / min for 2 minutes, the foam height was only 20 mm and the defoaming time was only 3 seconds. This proves that the defoaming composition 2 provided in Example 2 can play a more effective defoaming role on the MDEA solution. While controlling the foam height, it can eliminate foam in a short time, which is conducive to the stable circulation of amine liquid in the amine liquid absorption tower and avoids the problem of amine liquid foaming reducing the circulation volume and thus affecting the acid gas absorption effect of amine liquid circulation.

[0077] Example 3

[0078] The defoaming composition provided in this embodiment includes fluoroalkyl polyether modified siloxane, tert-butyldimethylsiloxane acetaldehyde, Tween 20, butanol and water;

[0079] The total mass of the defoaming composition is 100%, of which 6 wt% is fluoroalkyl polyether modified siloxane, 10 wt% is tert-butyldimethylsiloxane acetaldehyde, 0.5 wt% is Tween 20, 0.5 wt% is butanol, and 83 wt% is water.

[0080] The fluoroalkyl polyether modified siloxane used in this embodiment was purchased from Guangdong Sanqi New Materials Co., Ltd., product model 3007D.

[0081] This embodiment also provides an exemplary method for preparing an antifoaming composition according to the above formulation:

[0082] Weigh 6g of fluoroalkyl polyether modified siloxane, 10g of tert-butyldimethylsiloxane acetaldehyde, 0.5g of Tween 20, 0.5g of butanol and 83g of water, and stir until they are evenly mixed to obtain defoaming composition 3.

[0083] Test Example 3

[0084] According to the experimental procedure for determining foaming tendency in "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents", the defoaming ability of the defoaming composition 3 provided in Example 3 on MDEA solution was tested.

[0085] The MDEA concentration in the MDEA solution used in this test example is 45% (that is, the total mass of the MDEA solution is 100%, of which MDEA accounts for 45% by mass).

[0086] The specific testing steps are as follows:

[0087] (1) Take an appropriate amount of the defoaming composition 3 provided in Example 3, and add water to dilute the defoaming composition 3 while stirring to obtain the diluted defoaming composition 3; the total mass of the diluted defoaming composition 3 is 100%, of which the mass percentage of the defoaming composition 3 is 20%;

[0088] (2) Weigh 100 mL of 45% MDEA solution into the glass tube of the foaming evaluator and heat the glass tube in a water bath at 45°C until the temperature of the MDEA solution in the glass tube is the same as the temperature of the water bath. Then weigh 5 mg of the diluted defoaming composition 3 prepared in (1) and add it into the glass tube. Then, introduce nitrogen gas into the test solution (i.e., the mixture of MDEA solution and diluted defoaming composition 3) in the glass tube at a rate of 250 mL / min for 2 min.

[0089] (3) After the nitrogen flow is completed, turn off the nitrogen flow and record the height of the foam generated by the test liquid in the glass tube, and record the time it takes for the foam to completely disappear (i.e., the defoaming time).

[0090] The test results are shown in Table 3.

[0091] Table 3. Defoaming performance of defoaming composition 3

[0092]

[0093] As shown in Table 3, the defoaming composition 3 provided in Example 3, after being diluted to a concentration of 20% and added to a 45% MDEA solution, exhibits a significant defoaming and foam-suppressing effect: after nitrogen gas is introduced at a rate of 250 mL / min for 2 minutes, the foam height is controlled at 50 mm, and the defoaming time is 7 seconds, meeting the standard requirements. This demonstrates that the defoaming composition 3 provided in Example 3 can effectively defoam the MDEA solution, controlling the foam height and defoaming time within the standard requirements. This is beneficial for the stable circulation of amine liquid in the amine absorption tower, avoiding the problem of amine liquid foaming reducing the circulation volume and thus affecting the acid gas absorption effect of the amine liquid circulation.

[0094] Comparative Example 1

[0095] This comparative example provides a comparative defoaming composition, specifically replacing the dimethyl polyether siloxane in Example 1 with an equal mass of tert-butyldimethylsiloxane acetaldehyde, i.e., the comparative defoaming composition includes tert-butyldimethylsiloxane acetaldehyde, Tween 20, isopropanol and water;

[0096] The total mass of the comparative defoaming composition is 100%, of which 18 wt% is tert-butyldimethylsiloxane acetaldehyde, 1 wt% is Tween 20, 1 wt% isopropanol, and 80 wt% is water.

[0097] This comparative example also provides an exemplary method for preparing a comparative defoaming composition according to the above formulation:

[0098] Weigh 18g of tert-butyldimethylsiloxane acetaldehyde, 1g of Tween 20, 1g of isopropanol and 80g of water, and stir until they are mixed evenly to obtain a comparative defoaming composition.

[0099] Comparative test cases

[0100] According to the experimental procedure for determining foaming tendency in "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents", the defoaming ability of the comparative defoaming composition provided in Comparative Example 1 on MDEA solution was tested.

[0101] The MDEA concentration in the MDEA solution used in this test example is 45% (that is, the total mass of the MDEA solution is 100%, of which MDEA accounts for 45% by mass).

[0102] The specific testing steps are as follows:

[0103] (1) Take an appropriate amount of the comparative defoaming composition provided in Comparative Example 1, and add water to dilute it while stirring to obtain the diluted comparative defoaming composition; the total mass of the diluted comparative defoaming composition is taken as 100%, of which the mass percentage of the comparative defoaming composition is 30%;

[0104] (2) Weigh 100 mL of 45% MDEA solution into the glass tube of the foaming evaluator and heat the glass tube in a 45°C water bath until the temperature of the MDEA solution in the glass tube is the same as the temperature of the water bath. Then weigh 5 mg of the diluted comparative defoaming composition prepared in (1) and add it into the glass tube. Then, introduce nitrogen gas into the test solution (i.e., the mixture of MDEA solution and diluted comparative defoaming composition) in the glass tube at a rate of 250 mL / min for 2 min.

[0105] (3) After the nitrogen flow is completed, turn off the nitrogen flow and record the height of the foam generated by the test liquid in the glass tube, and record the time it takes for the foam to completely disappear (i.e., the defoaming time).

[0106] The test results are shown in Table 4.

[0107] Table 4. Defoaming performance of comparative defoaming compositions

[0108]

[0109] Table 4 shows that the comparative defoaming composition provided in Comparative Example 1, diluted to a concentration of 30%, showed poor defoaming and foam suppression effects when added to a 45% MDEA solution. After nitrogen was introduced at a rate of 250 mL / min for 2 minutes, the foam height was controlled at 55 mm, and the defoaming time was 7 seconds. Although the defoaming time of the comparative defoaming composition was within the range specified in the standard, its bubble height was significantly higher than 50 mm, failing to meet the standard's foam height requirement. This demonstrates that the comparative defoaming composition provided in Comparative Example 1 cannot effectively suppress the foaming phenomenon of the MDEA solution, which is detrimental to the stable circulation of the amine solution in the amine absorption tower.

[0110] A comprehensive analysis of the formulations of the defoaming compositions provided in Examples 1 to 3 and the defoaming performance test results of Examples 1 to 3 reveals that the dosage of each component in the defoaming compositions provided by this invention, especially the dosage of polyether-modified organosilicon surfactants and alkylsiloxane surfactants, affects the defoaming and foam-suppressing effect of the defoaming compositions on MDEA solutions. The defoaming compositions within the scope defined by this invention can effectively defoam MDEA solutions, reduce foam height, and shorten defoaming time, controlling the foam height of MDEA solutions to within 50 mm and the defoaming time to within 10 seconds, meeting the performance requirements for defoamers in the standard SY / T 6538-2016 "Formulated Selective Desulfurization Solvents". Comparing the formulations of Example 1 and Comparative Example 1, and the test results of Test Example 1 and Comparative Test Example, it can be seen that the comparative defoaming composition provided in Comparative Example 1 lacks polyether-modified organosilicon surfactants compared to the defoaming composition 1 provided in Example 1. Correspondingly, the mass ratio of alkylsiloxane surfactants in the comparative defoaming composition exceeds the 6-12 wt% range specified in this invention. This manifests as a significantly higher foaming height in the comparative test example compared to the upper limit of foaming height specified in the standard "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents," failing to provide sufficient foam suppression for MDEA solutions. In other words, the absence of components in the defoaming composition, as well as excessive or insufficient amounts of components, will deteriorate the defoaming and foam suppression performance of the defoaming composition, making it unable to meet the requirements of the standard "SY / T 6538-2016 Formulation-type Selective Desulfurization Solvents."

[0111] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. An antifoaming composition, characterized in that, This includes polyether-modified silicone surfactants, alkylsiloxane surfactants, Tween surfactants, low alcohols, and water.

2. The defoaming composition according to claim 1, characterized in that, The total mass of the defoaming composition is 100%, and the defoaming composition comprises 6-12 wt% of the polyether-modified silicone surfactant, 6-12 wt% of the alkylsiloxane surfactant, 0-1.5 wt% of the Tween surfactant, 0.1-1 wt% of the low alcohol and the balance being water.

3. The defoaming composition according to claim 1, characterized in that, The total mass of the defoaming composition is 100%, and the defoaming composition comprises 6-12 wt% of the polyether-modified silicone surfactant, 6-10 wt% of the alkylsiloxane surfactant, 0.5-1 wt% of the Tween surfactant, 0.5-1 wt% of the low alcohol and the balance being water.

4. The defoaming composition according to any one of claims 1 to 3, characterized in that, The polyether-modified silicone surfactants include at least one of polyether-modified polysiloxanes, alkyl polyether siloxanes, and fluoroalkyl polyether-modified siloxanes.

5. The defoaming composition according to any one of claims 1 to 3, characterized in that, The alkylsiloxane surfactant is at least one of polydimethylsiloxane, ethoxy-modified trisiloxane, and tert-butyldimethylsiloxane acetaldehyde.

6. The defoaming composition according to any one of claims 1 to 3, characterized in that, The Tween-type surfactants include Tween 20 and / or Tween 40.

7. The defoaming composition according to any one of claims 1 to 3, characterized in that, The lower alcohols include at least one of C2 to C4 alcohols.

8. The use of the defoaming composition according to any one of claims 1 to 7 in the defoaming of amine desulfurization liquid.

9. The application according to claim 8, characterized in that, The effective defoaming concentration of the defoaming composition is not less than 20%.

10. The application according to claim 8, characterized in that, The defoaming composition controls the foaming height of the amine desulfurization liquid to be no higher than 50 cm; and / or the defoaming time to be no longer than 10 s.

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