Absorbent, preparation method and application thereof, and method for treating methyl methacrylate waste gas

Abstract

The invention relates to the technical field of methyl methacrylate tail gas treatment, and discloses an absorbent for treating methyl methacrylate waste gas, a preparation method and application of the absorbent, and a method for treating the methyl methacrylate waste gas. The absorbent contains a composite component, a hydrogen bond acceptor and a hydrogen bond donor, the content molar ratio of the hydrogen bond acceptor to the hydrogen bond donor to the composite component is 1: (1-5): (0.02-0.2); the composite component is composed of a component A and a component B; the component A is citronellol and / or phenol, and the component B is acetone and / or diethyl ether; the hydrogen bond acceptor is selected from at least one of quaternary ammonium salt containing C1-C4 alkyl and quaternary phosphorus salt containing phenyl; the hydrogen bond donor is selected from at least one of levulinic acid and C8-C12 saturated monohydric alcohol. The absorbent has the advantages of being not prone to volatilization, economical, environmentally friendly and high in methyl methacrylate absorption capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of methyl methacrylate tail gas treatment, and specifically relates to an absorbent for treating methyl methacrylate waste gas, a preparation method and application thereof, and a method for treating methyl methacrylate waste gas. Background Art

[0002] Methyl methacrylate (MMA) is a monomer material for synthesizing polymethyl methacrylate and is also an important chemical raw material. It is a colorless and volatile liquid with a strong pungent odor. Its vapor can form an explosive mixture when mixed with air (lower explosion limit: 2.1% VOL). Therefore, the methyl methacrylate-containing tail gas generated during the production, use, transportation, etc. of methyl methacrylate must be treated by VOCs treatment before being discharged.

[0003] As a VOCs with a strong odor, the treatment methods of methyl methacrylate gas mainly include catalytic combustion method and recovery method. Since the VOCs content in the methyl methacrylate tail gas is usually low, about below 5000 mg / m3, the catalytic combustion method requires high energy consumption, and at the same time, the combustion product CO2 will increase carbon emissions. From the perspective of coordinated treatment of pollution reduction and carbon reduction, the recovery method has the dual significance of resource recycling and environmental protection. The recovery method mainly includes adsorption method and absorption method.

[0004] The adsorption method realizes the removal of methyl methacrylate through the adsorption of VOCs by porous materials mainly composed of activated carbon, and is suitable for the treatment of small-volume tail gas, but has poor treatment effect for large gas flow; in addition, the adsorption heat effect of activated carbon is significant, the temperature rises during the adsorption process, local "hot spots" may be generated, leading to potential safety hazards, the temperature drops during the desorption process, affecting the desorption efficiency and reducing the service life of carbon materials.

[0005] The absorption method realizes the removal of VOCs in the gas through the dissolution of the absorbent. Since methyl methacrylate has low solubility in water, a water-soluble absorbent cannot be used. Conventional organic solvents have a high saturated vapor pressure and strong volatility, and will cause secondary pollution problems as absorbents, and cannot achieve deep recovery of low-concentration VOCs gas. Ionic liquids have low volatility and can be designed in terms of functions, and can achieve a high VOCs recovery efficiency; however, ionic liquids are expensive, have a complex preparation process, and have certain toxicity, which limits their industrial promotion.

[0006] In order to reduce the emission of methyl methacrylate gas and improve production safety, it is necessary to provide an absorbent with high absorption capacity for methyl methacrylate, low volatility, economic and environmental protection to solve the technical problems in the current field of methyl methacrylate tail gas treatment. Summary of the Invention

[0007] The object of the present invention is to overcome the problems of low absorption capacity, poor absorption effect and easy volatility existing in the existing absorbents for methyl methacrylate.

[0008] To achieve the above object, in the first aspect of the present invention, an absorbent for treating methyl methacrylate waste gas is provided, and the absorbent contains a composite component, a hydrogen bond acceptor and a hydrogen bond donor;

[0009] The absorbent has a saturated vapor pressure < 100 Pa at 25 °C, a saturated water content of 0.1 mol% - 5 mol%, and a freezing point of < 5 °C;

[0010] The molar ratio of the contents of the hydrogen bond acceptor, the hydrogen bond donor and the composite component is 1:1 - 5:0.02 - 0.2;

[0011] The composite component is composed of component A and component B; and component A is citronellol and / or phenol, and component B is acetone and / or ether;

[0012] The hydrogen bond acceptor is selected from at least one of quaternary ammonium salts containing C1 - C4 alkyl groups and quaternary phosphonium salts containing phenyl groups;

[0013] The hydrogen bond donor is selected from at least one of levulinic acid and saturated monohydric alcohols with C8 - C12;

[0014] In the second aspect of the present invention, a method for preparing an absorbent for treating methyl methacrylate waste gas is provided, and the method includes the following steps:

[0015] Mix the hydrogen bond acceptor, the hydrogen bond donor and the composite component to obtain an absorbent for treating methyl methacrylate waste gas;

[0016] The molar ratio of the amounts used of the hydrogen bond acceptor, the hydrogen bond donor and the composite component is 1:1 - 5:0.02 - 0.2;

[0017] The definitions of the composite component, the hydrogen bond acceptor and the hydrogen bond donor are the same as those defined in the first aspect.

[0018] In the third aspect of the present invention, an absorbent for treating methyl methacrylate waste gas prepared by the method described in the second aspect is provided.

[0019] In the fourth aspect of the present invention, a method for treating methyl methacrylate waste gas is provided, and the method includes: bringing the absorbent described in the first aspect and / or the third aspect into contact with the waste gas containing methyl methacrylate.

[0020] The absorbent provided by the present invention contains a hydrogen bond acceptor, a hydrogen bond donor, and a composite component with a molar ratio of 1:1 - 5:0.02 - 0.2. The freezing points of these absorbents are all below 10°C, the saturated vapor pressure at 25°C is less than 100 Pa, they are not easily volatile, and they have a high absorption capacity for methyl methacrylate, enabling low-carbon and efficient recovery of VOCs. Detailed Embodiments

[0021] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0022] As described above, in the first aspect of the present invention, an absorbent for treating methyl methacrylate waste gas is provided, and the absorbent contains a composite component, a hydrogen bond acceptor, and a hydrogen bond donor;

[0023] The absorbent has a saturated vapor pressure < 100 Pa at 25°C, a saturated water content of 0.1 mol% - 5 mol%, and a freezing point of < 5°C;

[0024] The molar ratio of the contents of the hydrogen bond acceptor, the hydrogen bond donor, and the composite component is 1:1 - 5:0.02 - 0.2;

[0025] The composite component is composed of component A and component B; and component A is citronellol and / or phenol, and component B is acetone and / or ether;

[0026] The hydrogen bond acceptor is selected from at least one of quaternary ammonium salts containing C1 - C4 alkyl groups and quaternary phosphonium salts containing phenyl groups;

[0027] The hydrogen bond donor is selected from at least one of levulinic acid and saturated monohydric alcohols with C8 - C12;

[0028] Preferably, the absorbent has a saturated vapor pressure of 0.5 - 50 Pa at 25°C; a saturated water content of 0.1 mol% - 2 mol%; and a freezing point of < 0°C.

[0029] In the present invention, the saturated vapor pressure of the absorbent is measured by thermogravimetric analysis, and the saturated water content is measured according to the Karl Fischer titration method. The saturated water content x is calculated according to the following formula w :

[0030] x w = n w / (n w + S) × 100%; where n wn is the amount of substance of water, and S is the total molar amount of each component in the absorbent.

[0031] Preferably, the hydrogen bond acceptor is selected from at least one of quaternary ammonium salts containing C2-C4 alkyl groups and quaternary phosphonium salts containing phenyl groups.

[0032] Preferably, the quaternary ammonium salt containing C2-C4 alkyl groups is selected from at least one of tetraethylammonium chloride and tetrabutylammonium bromide. The inventors found that under this preferred condition, the obtained absorbent has a higher absorption capacity for methyl methacrylate.

[0033] Preferably, the quaternary phosphonium salt containing phenyl groups is selected from at least one of benzyltriphenylphosphonium bromide and methyltriphenylphosphonium chloride. The inventors found that under this preferred condition, the obtained absorbent has a lower freezing point and a higher removal rate of methyl methacrylate.

[0034] Preferably, in the composite component, the molar ratio of the content of component A to component B is 1:1-10. The inventors found that under this preferred condition, the obtained absorbent has a lower freezing point and a better absorption effect on methyl methacrylate.

[0035] According to a preferred specific embodiment, the hydrogen bond acceptor is a quaternary ammonium salt containing C2-C4 alkyl groups, the hydrogen bond donor is levulinic acid and / or n-octanol, and the molar ratio of the content of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3-5:0.1-0.2. The inventors found that under this preferred condition, the obtained absorbent has a better absorption effect on methyl methacrylate and a lower saturated vapor pressure.

[0036] Preferably, the hydrogen bond acceptor is tetraethylammonium chloride, the hydrogen bond donor is levulinic acid, and the molar ratio of the content of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3-5:0.1-0.2.

[0037] Preferably, the hydrogen bond acceptor is tetrabutylammonium bromide, the hydrogen bond donor is n-octanol, and the molar ratio of the content of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3-5:0.1-0.2.

[0038] According to a preferred specific embodiment, the hydrogen bond acceptor is a quaternary phosphonium salt containing phenyl groups, the hydrogen bond donor is a saturated monohydric alcohol with C8-C12, and the molar ratio of the content of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1-4:0.02-0.1. The inventors found that under this preferred condition, the obtained absorbent has a higher absorption capacity for methyl methacrylate and a lower saturated vapor pressure.

[0039] Preferably, the hydrogen bond acceptor is benzyltriphenylphosphonium bromide, the hydrogen bond donor is n-decanol, and the molar ratio of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1-4:0.02-0.1.

[0040] Preferably, the hydrogen bond acceptor is methyltriphenylphosphonium chloride, the hydrogen bond donor is lauryl alcohol, and the molar ratio of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1-4:0.02-0.1.

[0041] As described above, the second aspect of the present invention provides a method for preparing an absorbent for treating methyl methacrylate waste gas, the method comprising the following steps:

[0042] Mix the hydrogen bond acceptor, hydrogen bond donor, and composite component to obtain an absorbent for treating methyl methacrylate waste gas;

[0043] The molar ratio of the amounts of the hydrogen bond acceptor, hydrogen bond donor, and composite component used is 1:1-5:0.02-0.2;

[0044] The definitions of the composite component, hydrogen bond acceptor, and hydrogen bond donor are the same as those defined in the first aspect.

[0045] The amounts and types of the respective components involved in the second aspect of the present invention are the same as the contents and types of the corresponding components described in the first aspect of the present invention, and will not be elaborated here. Those skilled in the art should not consider this as a limitation of the present invention.

[0046] Preferably, in the composite component, the molar ratio of the content of component A to component B is 1:1-10.

[0047] Preferably, the mixing is carried out by one of heating and stirring or ultrasonic oscillation.

[0048] Preferably, the mixing is carried out under heating and stirring conditions, and the conditions for the mixing include: the temperature is 30-80 °C, the time is 30-90 min, and the rotation speed is 200-500 rpm.

[0049] Preferably, the mixing is carried out under ultrasonic oscillation conditions, and the conditions for the mixing include: the time of ultrasonic oscillation is 20-80 min, and the temperature is 30-80 °C.

[0050] It should be noted that the present invention has no special requirements for the frequency of the ultrasonic oscillation, and those skilled in the art can select according to needs.

[0051] As described above, the third aspect of the present invention provides an absorbent for treating methyl methacrylate waste gas prepared by the method described in the second aspect.

[0052] Preferably, the absorbent has an absorption capacity for methyl methacrylate > 100 g / kg at 25°C. In the present invention, the absorption capacity is determined by the saturated solubility measurement method.

[0053] As described above, the fourth aspect of the present invention provides a method for treating methyl methacrylate waste gas, which includes: contacting the absorbent described in the first aspect and / or the third aspect with the waste gas containing methyl methacrylate.

[0054] In the waste gas containing methyl methacrylate, the content of methyl methacrylate is 1000 - 5000 mg / m3.

[0055] Preferably, the feed volume ratio of the waste gas to the absorbent is 5 - 20:1. In this preferred case, the inventors found that the waste gas containing methyl methacrylate can better contact the absorbent, improving the absorption efficiency.

[0056] Preferably, the conditions for the contact include: temperature of 10 - 40°C, pressure of 0.1 - 0.5 MPa, and time of 0.2 - 2 min.

[0057] The present invention will be described in detail below through examples. In the following examples, the instruments, reagents, materials, etc. involved, unless otherwise specified, are all conventional instruments, reagents, materials, etc. existing in the prior art and can be obtained through regular commercial channels.

[0058] Example 1

[0059] This example is used to illustrate that the absorbent for treating methyl methacrylate waste gas according to the present invention is prepared according to the formula and process parameters in Table 1 and by the method described below.

[0060] The method for preparing the absorbent for treating methyl methacrylate waste gas includes the following steps:

[0061] Mix the hydrogen bond acceptor, hydrogen bond donor, and composite component to obtain the absorbent for treating methyl methacrylate waste gas;

[0062] The conditions for the mixing: stirring speed of 300 rpm, temperature of 80°C, and time of 40 min.

[0063] Examples 2 - 12 prepare the absorbent for treating methyl methacrylate waste gas according to the formula and process parameters in Table 1.

[0064] Table 1

[0065]

[0066] (Continued Table 1)

[0067]

[0068]

[0069] Comparative Example 1

[0070] In this comparative example, an absorbent was prepared by a method similar to that of Example 1, except that 0.02 mol of acetone was used to replace 0.02 mol of citronellol in this comparative example; the remaining steps were the same as those of Example 1.

[0071] Comparative Example 2

[0072] In this comparative example, an absorbent was prepared by a method similar to that of Example 1, except that 3 mol of oleic acid was used to replace 3 mol of levulinic acid in this comparative example; the remaining steps were the same as those of Example 1.

[0073] Comparative Example 3

[0074] In this comparative example, an absorbent was prepared by a method similar to that of Example 7, except that the amount of n-decanol used in this comparative example was 0.5 mol; the remaining steps were the same as those of Example 7.

[0075] Comparative Example 4

[0076] In this comparative example, an absorbent was prepared by a method similar to that of Example 7, except that the amount of n-decanol used in this comparative example was 6 mol; the remaining steps were the same as those of Example 7.

[0077] Comparative Example 5

[0078] In this comparative example, an absorbent was prepared by a method similar to that of Example 7, except that the amount of citronellol used in this comparative example was 0.002 mol; the remaining steps were the same as those of Example 7.

[0079] Test Example 1 Absorption Capacity Test

[0080] Methyl methacrylate gas was generated at 25°C and <2 kPa, and continuously passed into the absorbent prepared in the above examples until the content of methyl methacrylate in the absorbent could no longer increase (at 25°C and 101.3 kPa), it was considered to reach absorption saturation, and the absorption amount of the absorbent at this time was measured as the absorption capacity of the absorbent for methyl methacrylate.

[0081] Test Example 2

[0082] Removal Effect Test of Methyl Methacrylate Waste Gas

[0083] The removal of volatile organic compounds in the waste gas was completed in a packed absorption tower. The waste gas mainly contained nitrogen and methyl methacrylate, and the content of methyl methacrylate was 4021 mg / m 3, the packing is φ3mm Raschig rings, and the theoretical number of stages is 20; the waste gas and the VOCs eutectic absorbent flow into the packed absorption tower from the lower end and the upper end respectively, and the feed volume ratio of the waste gas to the absorbent is 8:1;

[0084] The waste gas and the absorbent are in countercurrent contact in the absorption tower. The contact temperature is 25°C, the contact pressure is 0.1 MPa, and the contact time is 1 min;

[0085] After absorption, the absorbent liquid is discharged from the bottom of the packed absorption tower; the purified gas is discharged from the top of the packed absorption tower. A detection device equipped with a flame ionization detector or a photoionization detector is used to detect the content of volatile organic compounds, and the removal rate R of methyl methacrylate is calculated;

[0086] R = (Y in, - Y out ) / Y in × 100%

[0087] where Y in represents the content of methyl methacrylate in the waste gas per unit time, and Y in represents the content of methyl methacrylate in the purified gas per unit time.

[0088] The specific test data are shown in Table 2 below.

[0089] Table 2

[0090]

[0091] From the results of the above table, it can be seen that the absorbent provided by the present invention has the characteristics of low saturated vapor pressure, hydrophobicity, and low freezing point, and the removal rate of methyl methacrylate at 25°C > 98%.

[0092] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An absorbent for treating methyl methacrylate waste gas, characterized in that, The absorbent contains a composite component, a hydrogen bond acceptor, and a hydrogen bond donor; The absorbent has a saturated vapor pressure < 100 Pa at 25 °C, a saturated water content of 0.1 mol% - 5 mol%, and a freezing point < 5 °C; The molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1 - 5:0.02 - 0.2; The composite component consists of component A and component B; and component A is citronellol and / or phenol, and component B is acetone and / or ether; The hydrogen bond acceptor is selected from at least one of quaternary ammonium salts containing C1 - C4 alkyl groups and quaternary phosphonium salts containing phenyl groups; The hydrogen bond donor is selected from at least one of levulinic acid and saturated monohydric alcohols with C8 - C12; 2. The absorbent according to claim 1, wherein, The absorbent has a saturated vapor pressure of 0.5 - 50 Pa at 25 °C; a saturated water content of 0.1 mol% - 2 mol%; and a freezing point < 0 °C.

3. The absorbent according to claim 1 or 2, wherein, The hydrogen bond acceptor is selected from at least one of quaternary ammonium salts containing C2 - C4 alkyl groups and quaternary phosphonium salts containing phenyl groups; Preferably, the quaternary ammonium salt containing C2 - C4 alkyl groups is selected from at least one of tetraethylammonium chloride and tetrabutylammonium bromide; Preferably, the quaternary phosphonium salt containing phenyl groups is selected from at least one of benzyltriphenylphosphonium bromide and methyltriphenylphosphonium chloride; 4. The absorbent according to any one of claims 1-3, wherein, In the composite component, the molar ratio of the contents of component A and component B is 1:1 - 10.

5. The absorbent according to any one of claims 1-4, wherein, The hydrogen bond acceptor is a quaternary ammonium salt containing C2 - C4 alkyl groups, the hydrogen bond donor is levulinic acid and / or n - octanol, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3 - 5:0.1 - 0.

2.

6. The absorbent according to any one of claims 1-5, wherein, The hydrogen bond acceptor is tetraethylammonium chloride, the hydrogen bond donor is levulinic acid, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3 - 5:0.1 - 0.2; Preferably, the hydrogen bond acceptor is tetrabutylammonium bromide, the hydrogen bond donor is n - octanol, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:3 - 5:0.1 - 0.

2.

7. The absorbent according to any one of claims 1 to 4, wherein, The hydrogen bond acceptor is a quaternary phosphonium salt containing phenyl groups, the hydrogen bond donor is a saturated monohydric alcohol with C8 - C12, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1 - 4:0.02 - 0.

1.

8. The absorbent according to any one of claims 1-4, wherein, The hydrogen bond acceptor is benzyltriphenylphosphonium bromide, the hydrogen bond donor is n - decanol, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1 - 4:0.02 - 0.1; Preferably, the hydrogen bond acceptor is methyltriphenylphosphonium chloride, the hydrogen bond donor is lauryl alcohol, and the molar ratio of the contents of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1 - 4:0.02 - 0.

1.

9. A method for preparing an absorbent for treating methyl methacrylate waste gas, characterized in that, This method includes the following steps: Mix the hydrogen bond acceptor, hydrogen bond donor, and composite component to obtain an absorbent for treating methyl methacrylate waste gas; The molar ratio of the amounts used of the hydrogen bond acceptor, hydrogen bond donor, and composite component is 1:1 - 5:0.02 - 0.2; The definitions and amounts of the composite component, hydrogen bond acceptor, and hydrogen bond donor are the same as the definitions and amounts described in any one of claims 1 - 8.

10. The method according to claim 9, wherein, The mixing method uses ultrasonic oscillation; the mixing conditions include: the time of ultrasonic oscillation is 20 - 80 min, and the temperature is 30 - 80 °C.

11. The method according to claim 9, wherein, The mixing method uses heating and stirring; the mixing conditions include: the temperature is 30 - 80 °C, the time is 30 - 90 min, and the rotation speed is 200 - 500 rpm.

12. An absorbent for treating methyl methacrylate waste gas prepared by the method according to any one of claims 9 - 11.

13. A method for treating methyl methacrylate waste gas, characterized in that, The method includes: contacting the absorbent according to any one of claims 1 - 8, 12 with the waste gas containing methyl methacrylate.

14. The method according to claim 13, wherein, The feed volume ratio of the waste gas to the absorbent is 5 - 20:1; Preferably, the contacting conditions include: the temperature is 10 - 40 °C, the pressure is 0.1 - 0.5 MPa, and the time is 0.2 - 2 min.

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