Oily tail gas treatment device and treatment method

Abstract

The invention relates to the technical field of oil-containing tail gas treatment, in particular to an oil-containing tail gas treatment device and method. The device comprises a shell which comprises a shell wall and a containing cavity defined by the shell wall; the multiple layers of adsorption assemblies are stacked in the containing cavity in the vertical direction and connected with the inner wall of the barrel; a tail gas inlet and a tail gas outlet which are communicated with the accommodating cavity are formed in the shell; from bottom to top, the extension direction of the tail gas inlet is located below the first layer of adsorption assembly, and the extension direction of the tail gas outlet is located above the last layer of adsorption assembly; the adsorption assembly comprises a porous material and is used for being in contact with the oil-containing tail gas and condensing condensable gas in the tail gas into liquid drops, the porous material is a super-hydrophobic melamine porous material, the super-hydrophobic melamine porous material contains a hydrophobic group, and the structure of the hydrophobic group contains carbonyl. The oil-containing tail gas adsorption device can reduce the replacement cost of the adsorbent.

Description

Technical Field

[0001] This invention relates to the field of oily exhaust gas treatment technology, and specifically to an oily exhaust gas treatment device and treatment method. Background Technology

[0002] Oily exhaust gas treatment is a crucial component of air pollution control in the petrochemical industry. Current main treatment methods include absorption, adsorption, condensation, and combustion. Adsorption is suitable for most fugitive oily exhaust gas emissions, with granular activated carbon and activated carbon fibers being the mainstream adsorbents. However, activated carbon has limited adsorption capacity, exhibiting good initial adsorption performance but significantly declining in the later stages. It also suffers from poor selective adsorption, and the adsorption process is exothermic, leading to severe temperature rises that threaten the safe and stable production of the petrochemical industry. Oily exhaust gas adsorption equipment using activated carbon as the adsorbent suffers from frequent adsorbent replacement and high replacement costs. Therefore, there is an urgent need for an oily exhaust gas treatment device with a large adsorption capacity and long-term adsorption performance. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of frequent adsorbent replacement and high replacement costs in existing oily exhaust gas adsorption equipment, and to provide an oily exhaust gas adsorption device and method. When using this device for oily exhaust gas adsorption treatment, it exhibits a large adsorption capacity and high adsorption efficiency.

[0004] To achieve the above objectives, a first aspect of the present invention provides an oily exhaust gas treatment device, comprising: a shell including a shell wall and a receiving cavity defined by the shell wall; a multilayer adsorption assembly stacked vertically within the receiving cavity and in contact with the inner wall of the shell; the shell having an exhaust gas inlet and an exhaust gas outlet communicating with the receiving cavity; from bottom to top, the exhaust gas inlet extends below the first layer of adsorption assembly, and the exhaust gas outlet extends above the last layer of adsorption assembly; the adsorption assembly includes a porous material for contacting the oily exhaust gas and condensing condensable gases in the exhaust gas into droplets, the porous material being a superhydrophobic melamine porous material containing hydrophobic groups, the hydrophobic groups containing carbonyl groups in their structure.

[0005] The second aspect of the present invention provides a method for treating oily exhaust gas, which is carried out in the oily exhaust gas treatment device of the present invention, comprising: the oily exhaust gas enters the receiving cavity from the exhaust gas inlet, and is contacted from bottom to top with the porous material in the multilayer adsorption component, and the exhaust gas after contact treatment is discharged through the exhaust gas outlet.

[0006] Through the above technical solution, the present invention has at least the following beneficial effects:

[0007] The oily exhaust gas adsorption device of this invention has a large adsorption capacity and strong adsorption selectivity, and can maintain excellent adsorption efficiency for a long time, thereby significantly extending the replacement cycle of the adsorbent and reducing the replacement cost of the adsorbent. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of an oil-containing exhaust gas adsorption device provided in a preferred embodiment of the present invention.

[0009] Figure 2 These are physical images and SEM images of the superhydrophobic melamine porous material S1.

[0010] Figure 3 These are thermogravimetric curves of superhydrophobic melamine porous materials S1, S2, and the unmodified melamine porous material matrix in Example 1.

[0011] Figure 4 These are physical images and SEM images of the superhydrophobic melamine porous material S10.

[0012] Figure 5 The images are physical photos and SEM images of the melamine porous material matrix prepared in Example 1.

[0013] Figure 6 These are the infrared spectra of superhydrophobic melamine porous materials S1, S9, S10, and D1.

[0014] Figure 7 for Figure 2 A magnified view of a specific area.

[0015] Figure 8 for Figure 2 Another enlarged view of a specific area

[0016] Explanation of reference numerals in the attached figures

[0017] 1—Elliptical head; 2—Shell; 3—Flange cover

[0018] 4—Fixed component 51—Lower vent plate 52—Upper and lower vent plates

[0019] 6—Supporting component; 7—Porous material; 8—Exhaust gas inlet

[0020] 9—Exhaust gas outlet; 10—Support frame; 11—Drain valve

[0021] 12—Exhaust valve Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] In this invention, unless otherwise stated, directional terms such as "up," "down," "left," and "right" generally refer to the up, down, left, and right as shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself; and "connection" includes both direct connection between two components and connection between two components through at least one intermediate component.

[0024] like Figure 1 As shown, the first aspect of the present invention provides an oily exhaust gas treatment device, the device comprising: a shell 2, including a shell wall and a receiving cavity defined by the shell wall; a multilayer adsorption assembly, the multilayer adsorption assembly being stacked vertically in the receiving cavity and in contact with the inner wall of the shell; the shell 2 is provided with an exhaust gas inlet 8 and an exhaust gas outlet 9 communicating with the receiving cavity; from bottom to top, the exhaust gas inlet 8 extends below the first layer of adsorption assembly, and the exhaust gas outlet 9 extends above the last layer of adsorption assembly; the adsorption assembly includes a porous material 7 for contacting the oily exhaust gas and condensing condensable gases in the exhaust gas into droplets, the porous material 7 being a superhydrophobic melamine porous material containing hydrophobic groups, the structure of which contains carbonyl groups.

[0025] The device of the present invention has a large adsorption capacity and strong adsorption selectivity, and can maintain excellent adsorption efficiency for a long time, which can significantly extend the replacement cycle of the adsorbent and reduce the replacement cost of the adsorbent.

[0026] According to a preferred embodiment of the present invention, the adsorption assembly includes a multilayer adsorbent layer formed of porous material (7), and the adsorbent layers are fixed together by a breathable plate.

[0027] According to a preferred embodiment of the present invention, the adsorption assembly includes a multilayer adsorbent layer composed of porous material (7) disposed in the accommodating cavity, a lower ventilator (51) tightly attached to the lower surface of each adsorbent layer, and an upper ventilator (52) tightly attached to the upper surface of each adsorbent layer, wherein the porous material 7 constitutes the adsorbent layer.

[0028] According to the present invention, the lower vent plate 51 can be fixed first, and then the porous material 7 can be inserted to form an adsorbent layer. Then, the upper vent plate 52 can be used on the upper surface of the adsorbent layer. The superhydrophobic melamine porous material in the present invention is a flexible material of sponge. In order to prevent oily exhaust gas from being discharged directly into the atmosphere through the exhaust gas outlet without passing through the porous material, the diameter of the porous material 7 is slightly larger than the inner diameter of the shell 5.

[0029] According to a preferred embodiment of the present invention, in the adsorption assembly, the upper permeable plate (52) of the nth adsorbent layer and the lower permeable plate (51) of the (1+n)th adsorbent layer are fixedly connected by a support member (6) and form a gas flow channel, where n is an integer not less than 1, preferably n is 2-10, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, and more preferably 3-5.

[0030] According to a preferred embodiment of the present invention, the height of the adsorbent layer is 1 / 3 to 1 / 2 of the vertical distance between two adjacent lower permeable plates 51.

[0031] According to the present invention, in order to enable the exhaust gas to come into contact with the adsorbent and achieve adsorption, the upper and lower venting plates each have holes.

[0032] According to the present invention, as long as the purpose of the present invention can be achieved, the pore size of the openings on the upper and lower breathable layers is not particularly limited, and the inner diameter only needs to be slightly smaller than the particle size of the adsorbent. Preferably, the pore size is 5-20 mm.

[0033] According to a preferred embodiment of the present invention, the device further includes a lower end cap that is sealed to the lower end of the housing 2 and an upper end cap that is sealed to the upper end of the housing 2, wherein the lower end cap and the first adsorption assembly form a liquid collection cavity.

[0034] In this invention, there is no particular limitation on the way the lower end of the housing 2 is sealed to the lower end cap, for example, it can be connected by welding; there is no particular way the upper end of the housing 2 is sealed to the upper end cap, for example, it can be connected by a flange.

[0035] According to a preferred embodiment of the present invention, a drain valve 11 is provided below the lower end cap for draining the collected droplets.

[0036] According to a preferred embodiment of the present invention, a support frame 10 is provided below the lower end cap.

[0037] According to the present invention, in order to prevent excessive pressure, the upper end cap is provided with a vent valve 12.

[0038] According to the present invention, as long as the purpose of the present invention can be achieved, the specific form of the lower end cap and the upper end cap is not particularly limited. In one embodiment, the lower end cap and the upper end cap are each an elliptical end cap, a dished end cap, a semi-circular end cap, or a flat end cap.

[0039] According to a preferred embodiment of the present invention, the lower end cap is an elliptical end cap 1.

[0040] According to a preferred embodiment of the present invention, the lower end cap is a flat end cap, namely a flange cover 3.

[0041] According to the present invention, the hydrophilic groups in the melamine porous material matrix are hydrolyzed to obtain the superhydrophobic melamine porous material containing hydrophobic groups.

[0042] According to the present invention, those skilled in the art will understand that existing melamine porous material matrices have a melamine backbone, and the free amino groups and ether bonds connecting the melamine backbone in the melamine backbone are all hydrophilic groups. In the present invention, the hydrophobic groups are obtained by hydrolysis of the hydrophilic groups in the melamine porous material matrix, preferably with a hydrolysis rate of 5%-85%, for example 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, more preferably 10%-60%, and more preferably 15%-50%. That is, the carbonyl group (C=O) in the present invention is obtained by conversion of the free amino groups in the melamine backbone in the melamine porous material matrix, and the carbonyl group is located on the melamine backbone. The foregoing embodiments are beneficial for improving the oil and gas adsorption efficiency of the device beneficial to the present invention during long-term operation.

[0043] According to a preferred embodiment of the present invention, the hydrophilic group is selected from ether bonds and / or amino groups.

[0044] According to a preferred embodiment of the present invention, the porous material 7 has through holes.

[0045] According to the present invention, the pore size of the porous material 7 can be selected from a wide range. In a preferred embodiment, the pore size of the porous material 7 is 50-800 μm, preferably 100-400 μm.

[0046] According to the present invention, the porosity of the porous material 7 can be selected from a wide range. In a preferred embodiment, the porosity of the porous material (7) is greater than or equal to 80%, preferably greater than or equal to 93%, and more preferably 93%-98%.

[0047] The porous material in this invention has hydrophobic and oleophilic properties. Preferably, the static planar contact angle of the porous material 7 with water in air is not less than 125°, for example, 125°, 128.5°, 138.7°, 139.2°, 139.7°, 141°, 138.3°, 141.3°, 145.3°, more preferably not less than 135°, and more preferably 135°-150°. Preferably, the static contact angle of the porous material 7 with white oil is not higher than 20°, for example, 0°.

[0048] According to the present invention, the porous material 7 has flame-retardant and temperature-resistant properties. In one embodiment, the UL-94 vertical burning test rating of the porous material (7) is V-0. In another embodiment, the long-term temperature range of the porous material (7) is -150-200℃.

[0049] According to a preferred embodiment of the present invention, the preparation method of the hydrophobic melamine porous material includes: contacting the melamine porous material matrix with an acid solution and then subjecting it to microwave irradiation, washing, and drying to obtain the superhydrophobic melamine porous material.

[0050] According to the present invention, those skilled in the art will understand that existing melamine porous material matrices have a melamine backbone, and the free amino groups and ether bonds connecting the melamine backbone in the melamine backbone are all hydrophilic groups. In the present invention, the hydrophobic groups are obtained by hydrolysis of the hydrophilic groups in the melamine porous material matrix, preferably with a hydrolysis rate of 5%-85%, for example 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, more preferably 10%-60%, and more preferably 15%-50%. That is, the carbonyl group (C=O) in the present invention is obtained by conversion of the free amino groups in the melamine backbone in the melamine porous material matrix, and the carbonyl group is located on the melamine backbone. The foregoing embodiments are beneficial for improving the oil and gas adsorption efficiency of the device beneficial to the present invention during long-term operation.

[0051] In this invention, those skilled in the art will know that existing melamine porous material matrices have a melamine backbone, and the melamine backbone contains hydrophilic groups including free amino groups and ether bonds connecting the melamine backbone. After selectively absorbing microwave energy, the hydrophilic groups in the melamine porous material matrix partially hydrolyze into hydrophobic groups, and the free amino groups in the melamine backbone are converted into carbonyl groups; the ether bonds connecting the melamine backbone (~HN-COC-NH~) are converted into ~HN-CH2-NH~ structures.

[0052] According to a preferred embodiment of the present invention, the hydrophilic groups in the melamine porous material matrix are selected from ether bonds and / or amino groups.

[0053] According to a preferred embodiment of the present invention, the concentration of the acid solution is 0.01-3 mol / L, for example, it can be 0.08 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L, or 1.8 mol / L. Preferably, the concentration of the acid solution is 0.05-2 mol / L, and more preferably 0.05-1.5 mol / L. The foregoing embodiments are beneficial for improving the oil and gas adsorption efficiency of the device of the present invention during long-term operation.

[0054] According to a preferred embodiment of the present invention, the contact time is 0.5-100s, for example, it can be 0.5s, 0.8s, 1.0s, 2.0s, 3.0s, 4.0s, 5.0s, 6.0s, 7.0s, 8.0s, 9.0s, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, or 100s, preferably 0.5-10s.

[0055] The microwave irradiation conditions include: an irradiation power of 100-2000W, such as 100W, 200W, 300W, 400W, 500W, 600W, 700W, 900W, 1000W, 1100W, 1200W, 1300W, 1400W, 1500W, 1600W, 1700W, 1800W, 1900W, 2000W, preferably 100-1800W; and an irradiation time of 20s-20min, such as 20s, 1min, 2min, 5min, 10min, 15min, 20min, preferably 2min-10min.

[0056] According to the present invention, it is understood that the acid solution is obtained by mixing the corresponding acid with water, and in one embodiment, the acid in the acid solution is selected from inorganic acids and / or organic acids.

[0057] According to a preferred embodiment of the present invention, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, boric acid and phosphoric acid, preferably at least one of hydrochloric acid and sulfuric acid.

[0058] According to a preferred embodiment of the present invention, the organic acid is selected from at least one of acetic acid, citric acid, formic acid and oxalic acid, preferably citric acid and / or acetic acid.

[0059] According to a preferred embodiment of the present invention, the acid is selected from one or more of hydrochloric acid, citric acid, acetic acid and sulfuric acid; the acid concentration is 0.05-0.5 mol / L; the contact time between the melamine porous material matrix and the acid solution is 2s-10s; and the microwave irradiation time is 2min-10min.

[0060] In this invention, there is no particular limitation on the contact method, as long as the acid solution can be fully contacted with the skeleton of the melamine porous material matrix. The contact method includes, but is not limited to, immersion, rinsing, spraying, etc. Immersion is preferred, so that the acid solution can be more evenly distributed in the sponge skeleton. It can be understood that during immersion, the hydrophobic melamine porous material is completely immersed in the acid solution.

[0061] According to a preferred embodiment of the present invention, the melamine porous material matrix is ​​completely immersed in an acid solution for the contact, and then removed and subjected to microwave irradiation.

[0062] In this invention, the microwave irradiation can be carried out in various microwave reactors that are already available in the prior art.

[0063] In this invention, washing is used to remove hydrolysis products and acids from the surface of the material. There are no particular limitations on the washing conditions and the amount of detergent used. In the implementation of this invention, washing with deionized water until the washing solution is neutral is used as an example, but this does not limit the scope of this invention.

[0064] In this invention, there is no particular limitation on the drying method. According to a preferred embodiment of the invention, the drying method is selected from vacuum drying, forced air drying or microwave drying; more preferably, microwave drying is preferred because it has higher evaporation efficiency and is more energy-efficient.

[0065] In this invention, the range of selectable drying conditions is relatively wide. The preferred drying temperature is one that does not decompose the superhydrophobic melamine porous material. According to a preferred embodiment of this invention, the drying conditions include: a drying temperature of 60-100°C and a drying time of 5-120 min. In this embodiment of the invention, drying at 60°C for 10 min is used as an example, but this does not limit the scope of the invention.

[0066] like Figure 1 As shown, the second aspect of the present invention provides a method for treating oily exhaust gas, which is carried out in the oily exhaust gas treatment device of the present invention, including: oily exhaust gas entering the receiving cavity from the exhaust gas inlet 8, and contacting the porous material 7 in the multilayer adsorption component from bottom to top, and the exhaust gas after contact treatment being discharged through the exhaust gas outlet 9.

[0067] In this invention, the adsorption method described herein is used, and the superhydrophobic melamine porous material has good saturated adsorption capacity and long-term adsorption efficiency for oily exhaust gas, with a saturated adsorption capacity greater than 10 g / g and an adsorption efficiency greater than 98% within three weeks.

[0068] In this invention, the types, concentrations, and volumes of the oily exhaust gas can be selected from a wide range. According to a preferred embodiment of this invention, the oily exhaust gas includes non-methane hydrocarbons, with the remainder being N2. Preferably, the content of non-methane hydrocarbons in the oily exhaust gas is less than 10,000 ppm and not 0 ppm.

[0069] According to the present invention, non-methane hydrocarbons refer to benzene series compounds and C2-C5 hydrocarbons.

[0070] According to a preferred embodiment of the present invention, the conditions for the contact treatment include: a temperature of room temperature and a gas hourly space velocity (GHSV) of 1000-50000 h⁻¹ for the oily exhaust gas. -1 .

[0071] According to a preferred embodiment of the present invention, the oil-containing exhaust gas contains 0.1-1% by volume of benzene series compounds; the content of C2-C5 hydrocarbons is less than 0.1% by volume, and the remainder is air.

[0072] In this invention, unless otherwise specified, room temperature refers to 20-30°C.

[0073] The present invention will be described in detail below through embodiments.

[0074] In the context of this specification, including the following preparation examples, the hydrolysis rate of the hydrophilic groups was calculated by Agilent's micro-infrared spectroscopy using the ATR test mode. (1625±5 cm⁻¹) -1 The fitted peak area at 1480 cm⁻¹ divided by 1480 cm⁻¹ -1 The ratio of the fitted peak area (S) is correlated with the hydrolysis rate (H). The hydrolysis rate of the melamine porous material matrix is ​​0%, and the hydrolysis rate of the fully hydrolyzed sample, i.e., the infrared peak area ratio does not increase with the modification time, is 100%. The calculation yields H = 1.2S * 100%, and then the hydrolysis rate is obtained according to the formula and the test ratios of various examples.

[0075] In the context of this specification, including the following preparation examples, the vertical flammability test rating is tested according to the UL94 flame retardant test method.

[0076] In the context of this specification, including the following preparation examples, the water contact angle parameters were measured using an EASY DROP contact angle meter from KRUSS GmbH, Germany. The measurement range was 1-180°, with a resolution of ±0.1°. The static contact angle measurement mode was used, with a fixed volume of 2 μL of water or white oil droplets dropped onto the porous material each time. The calculated initial contact angle was taken as the contact angle measurement value of the porous material surface. Six parallel measurements were performed, and the average value was calculated.

[0077] In the following embodiments, the adsorption efficiency (η) of the oily exhaust gas was tested using the following steps: the oil and gas discharge port with a stable flow rate and a non-methane total hydrocarbon content of c1 (benzene series content of 3000ppm and C2-C5 hydrocarbon content of 1000ppm) was selected for testing. The oily exhaust gas treatment equipment was connected to the above-mentioned oil and gas discharge port in a sealed manner through a flange connection, and the non-methane total hydrocarbon content c2 at the pipe outlet was tested for a certain period of time.

[0078] Oil and gas adsorption efficiency

[0079] In the following preparation examples, the melamine porous material matrix was purchased from Beiyou Building Materials and is a melamine porous material with through pores.

[0080] Example of porous material preparation

[0081] Preparation Example 1

[0082] Prepare a 0.05 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 95%, average pore size 100 μm) in the solution for 2 seconds, then remove it. After irradiation with 800 W microwave power for 4 minutes, remove it, wash with deionized water until the pH is neutral, and microwave dry it (control the drying temperature at 60℃ for 10 minutes) to obtain the superhydrophobic melamine porous material S1.

[0083] The infrared spectrum of the superhydrophobic melamine porous material S1 is as follows: Figure 6 As shown, the hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​18%. The resulting superhydrophobic melamine porous material S1 has an average pore size of 100 μm, a porosity of 95%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 138.3°.

[0084] Among them, the physical image and SEM image of the superhydrophobic melamine porous material S1 are as follows: Figure 2 As shown, compared to the melamine porous material matrix (physical image and SEM image as shown) Figure 5 The size of the porous material skeleton and the overall size of the porous material did not change significantly. This indicates that the superhydrophobic porous material obtained by melamine porous material treatment has little effect on the pore size and porosity of the porous material matrix.

[0085] Preparation Example 2

[0086] Prepare a 0.5 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 93%, average pore size 300 μm) in it for 5 s, then remove it, irradiate it with a microwave irradiation power of 1800 W for 2 min, wash it with deionized water until the pH is neutral, and then microwave dry it (control the drying temperature at 80℃ for 80 min) to obtain the superhydrophobic melamine porous material S2.

[0087] The infrared spectrum of the superhydrophobic melamine porous material S2 is similar to that of Example 1. The hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​50%. The average pore size of the obtained superhydrophobic melamine porous material S2 is 300 μm, the porosity is 93.2%, the UL94 vertical flammability rating is V-0, the contact angle with white oil is 0°, and the contact angle with water is 145.3°.

[0088] Thermogravimetric curves of superhydrophobic melamine porous materials S1, S2, and the unmodified melamine porous material matrix in Example 1 are shown below. Figure 3 As shown, by Figure 3 It can be seen that the superhydrophobic melamine porous materials S1 and S2 have good temperature resistance, indicating that the modified materials have no change in temperature resistance below 200℃ and can be recycled by steam purging.

[0089] Preparation Example 3

[0090] Prepare a 0.25 mol / L citric acid aqueous solution, immerse the melamine porous material matrix (porosity 96%, average pore size 400 μm) in the solution for 10 s, then remove it, irradiate it with a microwave power of 200 W for 10 min, wash it with deionized water until the pH is neutral, and then microwave dry it (controlling the drying temperature at 60℃ for 50 min) to obtain the superhydrophobic melamine porous material S3.

[0091] The infrared spectrum of the superhydrophobic melamine porous material S3 is similar to that of Example 1. The hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​35%. The superhydrophobic melamine porous material S3 has an average pore size of 400 μm, a porosity of 96.6%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 141.3°.

[0092] Preparation Example 4

[0093] The method of preparation Example 3 was followed, except that a 0.25 mol / L boric acid aqueous solution was used instead of a 0.25 mol / L citric acid aqueous solution; the other conditions were the same as in Example 3, and the superhydrophobic melamine porous material S4 was obtained.

[0094] The infrared spectrum of the superhydrophobic melamine porous material S4 is similar to that of Example 1. The hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​20%. The superhydrophobic melamine porous material S3 has an average pore size of 400 μm, a porosity of 96.1%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 128.5°.

[0095] Preparation Example 5

[0096] A 2 mol / L oxalic acid aqueous solution was prepared, and the melamine porous material matrix (porosity 95%, average pore size 100 μm) was immersed in it for 50 s and then removed. After that, it was irradiated with microwave power of 1800 W for 2 min and then removed. It was washed with deionized water until the pH was neutral, microwave dried, and the drying temperature was controlled at 60℃. After drying for 10 min, the superhydrophobic melamine porous material S5 was obtained.

[0097] The infrared spectrum of the superhydrophobic melamine porous material S5 is similar to that of Example 1. The hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​58%. The average pore size of the superhydrophobic melamine porous material S5 is 90 μm, the porosity is 86%, the UL94 vertical flammability rating is V-0, the contact angle to white oil is 0°, and the contact angle to water is 139.7°.

[0098] Preparation Example 6

[0099] Following the method of Example 1, except that the microwave irradiation time was 15 min, and the other conditions were the same as in Example 1, a superhydrophobic melamine porous material S6 was obtained.

[0100] The infrared spectrum of the superhydrophobic melamine porous material S6 is similar to that of Example 1. The hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​56%. The average pore size of the obtained superhydrophobic melamine porous material S6 is 100 μm, the porosity is 84%, the UL94 vertical flammability rating is V-0, the contact angle to white oil is 0°, and the contact angle to water is 141.0°.

[0101] Preparation Example 7

[0102] The method of Example 1 was followed, except that 0.05 mol / L nitric acid was used instead of 0.05 mol / L hydrochloric acid, and the other conditions were the same as in Example 1, to obtain the superhydrophobic melamine porous material S7.

[0103] The infrared spectrum of the superhydrophobic melamine porous material S7 is similar to that of Example 1, with a hydrolysis rate of 14% for the hydrophilic groups. The superhydrophobic melamine porous material S7 has an average pore size of 100 μm, a porosity of 93.3%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 138.7°.

[0104] Preparation Example 8

[0105] The method of Example 1 was followed, except that the melamine porous material matrix (porosity of 95% and average pore size of 100 μm) was immersed in hydrochloric acid for 90 seconds and then removed. The other conditions were the same as in Example 1, and the superhydrophobic melamine porous material S8 was obtained.

[0106] The infrared spectrum of the superhydrophobic melamine porous material S8 is similar to that of Example 1, with a hydrolysis rate of 42% for the hydrophilic groups. The superhydrophobic melamine porous material S8 has an average pore size of 95 μm, a porosity of 88%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 139.2°.

[0107] Preparation Example 9

[0108] Prepare a 0.01 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 95%, average pore size 100 μm) in it for 2 s, then remove it and irradiate it with a microwave irradiation power of 200 W for 20 s. After that, remove it and microwave dry it (control the drying temperature at 60℃, dry for 10 min) to obtain the superhydrophobic melamine porous material S9.

[0109] The infrared spectrum of the superhydrophobic melamine porous material S9 is as follows: Figure 6 As shown, the hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​5%. The resulting superhydrophobic melamine porous material S9 has an average pore size of 100 μm, a porosity of 95%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 82.5°.

[0110] Preparation Example 10

[0111] A 3 mol / L nitric acid aqueous solution was prepared, and the melamine porous material matrix was immersed in it for 60 seconds and then removed. After that, it was irradiated with a microwave irradiation power of 2000W for 10 minutes and then removed for microwave drying. The drying temperature was controlled at 60℃ and dried for 60 minutes to obtain the superhydrophobic melamine porous material S10.

[0112] The infrared spectrum of the superhydrophobic melamine porous material S10 is as follows: Figure 6 As shown, the hydrolysis rate of the hydrophilic groups in the melamine porous material matrix is ​​82%. The resulting superhydrophobic melamine porous material S10 has an average pore size of 67 μm, a porosity of 53%, a UL94 vertical flammability rating of V-0, a white oil contact angle of 0°, and a water contact angle of 147.8°.

[0113] Figure 4 Here are the physical images and SEM images of the superhydrophobic melamine porous material S10, compared to the superhydrophobic melamine porous material S1 ( Figure 2The superhydrophobic melamine porous material S10 underwent a certain degree of collapse, with a reduction in porosity and pore size. This indicates that under these conditions, the high hydrolysis rate of the hydrophilic groups reduced the rigidity of the porous material framework compared to the superhydrophobic melamine porous material S1.

[0114] Comparative Preparation Example 1

[0115] The porous material is the melamine porous material matrix (porosity 95%, average pore size 100 μm) from Preparation Example 1, denoted as D1 (unmodified melamine porous material matrix), and its infrared spectrum is shown below. Figure 6 As shown, the physical image and SEM image of the melamine porous material matrix are as follows. Figure 5 As shown.

[0116] Comparative Preparation Example 2

[0117] The porous material is activated carbon, denoted as D2.

[0118] Comparative preparation example 3

[0119] The method is the same as in Example 1, except that microwave irradiation is not performed. Specifically:

[0120] Prepare a 0.05 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 95%, average pore size 100 μm) in the solution for 2 seconds, remove it, let it stand for 4 minutes, wash it with deionized water until the pH is neutral, microwave dry it at 60℃ for 10 minutes to obtain melamine porous material D3.

[0121] The obtained superhydrophobic melamine porous material D3 has a hydrolysis rate of 0% for hydrophilic groups, an average pore size of 100 μm, and a porosity of 95%.

[0122] Comparative preparation example 4

[0123] The method of Example 2 differs from that microwave irradiation was not performed; specifically:

[0124] Prepare a 0.5 mol / L hydrochloric acid aqueous solution, immerse the melamine porous material matrix (porosity 93%, average pore size 300 μm) in it for 5 s, remove it, let it stand for 2 min, wash it with deionized water until the pH is neutral, and then microwave dry it at 80℃ for 80 min to obtain melamine porous material D4.

[0125] In melamine porous material D4, the hydrolysis rate of hydrophilic groups is 0%, the average pore size is 300 μm, and the porosity is 93%.

[0126] Figure 7 for Figure 2 A close-up view of a specific area; Figure 8 for Figure 2 Another magnified view of a specific area, based on Figure 6-8 It can be seen that: 1628cm -1 The characteristic peak at 1480 cm⁻¹ is a new peak generated after modification, that is, the characteristic peak of the hydrophobic group. -1 The peak at 1540 cm⁻¹ represents the stretching vibration peak of the melamine ring. Since the modification did not destroy the melamine ring, its intensity remains unchanged. The area of ​​this peak can be used to characterize the initial content of hydrophilic groups. -1 This is the CN stretching vibration. According to the S9, S1, and S10 peaks, as the hydrolysis rate of the melamine porous material matrix increases and the degree of modification increases, this peak gradually weakens, while the peak at 1624 cm⁻¹... -1 This peak represents the stretching vibration of cyclic amides and gradually increases in intensity. It is speculated that the free amino groups on the melamine-formaldehyde resin gradually hydrolyze into hydroxyl groups under acidic conditions. The hydroxyl groups on the melamine ring are unstable and exist as isomers of lactams. (1141 cm⁻¹) -1 and 967cm - S1 represents the symmetric and antisymmetric absorption peaks in the COC bond. The intensity of these two absorption peaks gradually decreases with the increase of the hydrolysis rate of the melamine porous material matrix and the degree of modification, according to S9, S1, and S10, until they disappear. This indicates that after the melamine porous material matrix is ​​modified, the NCOCN structure in the melamine-formaldehyde sponge undergoes a deformaldehyde reaction, thereby generating the NCN structure.

[0127] Example

[0128] Methods for treating oily exhaust gases include, for example Figure 1 Performed in the aforementioned apparatus, such as Figure 1 As shown, porous material 8 is laid on five layers of lower permeable plates 51 (pore diameter 10mm) to form five adsorbent layers (with the same height). Each adsorbent layer is pressed down by an upper permeable plate 51. The upper permeable plate 52 (pore diameter 10mm) in the first adsorption assembly is fixedly connected to the lower permeable plate 51 in the (1+n)th adsorption assembly by a support member 6, where n is 4. The height of each adsorbent layer is 1 / 2 of the vertical distance between two adjacent lower permeable plates 51. The lower permeable plates 51 in the first adsorption assembly are fixed on metal fasteners 4. The adsorption method is as follows:

[0129] Oily exhaust gas is introduced into the receiving cavity through exhaust gas inlet 8. The oily exhaust gas flows from bottom to top through a parallel five-layer support plate 7 and a porous material 8. The oily exhaust gas and the porous material 8 are in full contact at room temperature for adsorption. After adsorption, the exhaust gas liquefies and detaches from the porous material 8 under gravity, entering the liquid collection chamber. The treated oily exhaust gas is discharged through exhaust gas outlet 9. The liquid droplets collected in the liquid collection chamber are discharged through drain valve 11. Finally, the oily exhaust gas is discharged through drain valve 11.

[0130] The non-methane total hydrocarbons (including benzene series compounds and C2-C5 hydrocarbons) in the oil-containing exhaust gas were 3000 ppm, with the remainder being nitrogen, and the gas hourly space velocity was 6000 h⁻¹. -1 The gas volume is 100 Nm³. 3 / h;

[0131] Among them, the porous material (8) is the porous material in the preparation example and the comparative preparation example, respectively.

[0132] The adsorption results are shown in Table 1.

[0133] Table 1

[0134]

[0135]

[0136] As can be seen from the results in Table 1, the oily exhaust gas treatment device of the present invention has a large adsorption capacity and strong adsorption selectivity for treating exhaust gas, which can significantly extend the replacement cycle of the adsorbent and reduce the replacement cost of the adsorbent.

[0137] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An oil-containing exhaust gas treatment device, characterized by, The device comprises: a shell (2) comprising a shell wall and a containing cavity defined by the shell wall; a plurality of adsorption assemblies stacked in a vertical direction within the containing cavity and in contact with the inner wall of the cylinder; the shell (2) is provided with a tail gas inlet (8) and a tail gas outlet (9) communicating with the containing cavity; from bottom to top, the extension direction of the tail gas inlet (8) is below the first layer of adsorption assemblies, and the extension direction of the tail gas outlet (9) is above the last layer of adsorption assemblies; the adsorption assembly comprises a porous material (7) for contacting oil-containing tail gas to condense condensable gas in the tail gas into droplets, the porous material (7) is a super-hydrophobic melamine porous material, the super-hydrophobic melamine porous material contains a hydrophobic group, and the structure of the hydrophobic group contains a carbonyl group.

2. The device according to claim 1, wherein the adsorption assembly comprises a plurality of adsorbent layers formed by the porous material (7), and each layer of adsorbent layers is fixed by a gas-permeable plate; preferably, the adsorption assembly comprises a plurality of adsorbent layers formed by the porous material (7) within the containing cavity, a lower gas-permeable plate (51) closely adhered to the lower surface of each layer of adsorbent layers, and an upper gas-permeable plate (52) closely adhered to the upper surface of each layer of adsorbent layers; preferably, in the adsorption assembly, the upper gas-permeable plate (52) of the nth layer of adsorbent layers is fixedly connected with the lower gas-permeable plate (51) in the 1+nth layer of adsorbent layers through a support (6), and forms a gas flow channel, n is an integer not less than 1, preferably n is 2-10, further preferably 3-5; and / or the height of the adsorbent layer is 1 / 3-1 / 2 of the vertical distance between two adjacent lower gas-permeable plates (51); and / or the device comprises a fixing member (4) sealingly arranged in the containing cavity for fixing the lower gas-permeable plate (51) in the first layer of adsorption assemblies; and / or the upper gas-permeable plate and the lower gas-permeable plate each have holes, preferably with a hole diameter of 5-20 mm.

3. The device according to claim 1 or 2, wherein the device further comprises a lower head sealingly connected to the lower end of the shell (2) and an upper head sealingly connected to the upper end of the shell (2), and the lower head forms a liquid collection cavity with the first layer of adsorption assemblies; preferably, a liquid discharge valve (11) is arranged below the lower head for discharging the collected droplets; and / or a support frame (10) is arranged below the lower head; and / or an emptying valve (12) is arranged on the upper head; and / or the lower head and the upper head are each an elliptical head, a disc-shaped head, a semi-circular head or a flat plate head; more preferably, the lower head is an elliptical head (1); and / or the lower head is a flat plate head.

4. The device according to any one of claims 1-3, wherein the super-hydrophobic melamine porous material containing a hydrophobic group is obtained by hydrolysis of a hydrophilic group in a melamine porous material matrix; preferably, the hydrolysis rate is 5%-85%, preferably 10%-60%, more preferably 15%-50%; and / or the hydrophilic group is selected from an ether bond and / or an amino group.

5. The device according to any one of claims 1-4, wherein The porous material (7) has through holes; Preferably, the pore size of the porous material (7) is 50-800 μm, preferably 100-400 μm; and / or The porosity of the porous material (7) is greater than or equal to 80%, preferably greater than or equal to 93%.

6. The device according to any one of claims 1-5, wherein, The static planar contact angle of the porous material (7) with water in air is not less than 125°, preferably not less than 135°; and / or The static contact angle of the porous material (7) with white oil is not higher than 20°; and / or The UL-94 vertical burning test grade of the porous material (7) is V-0; and / or The long-term tolerance temperature range of the porous material (7) is -150-200℃.

7. The device according to any one of claims 1-6, wherein, The preparation method of the hydrophobic melamine porous material comprises: contacting a melamine porous material matrix with an acid solution, then performing microwave irradiation, washing, and drying to obtain a super-hydrophobic melamine porous material; Preferably, The concentration of the acid solution is 0.01-3 mol / L; preferably 0.05-1.5 mol / L; The contact time is 0.5-100 s; The microwave irradiation conditions include: irradiation power is 100-2000 W; irradiation time is 20 s-20 min; The hydrophilic group in the melamine porous material matrix is selected from ether bond and / or amino group.

8. The device according to claim 7, wherein, In the acid solution, the acid is selected from inorganic acid and / or organic acid; Preferably, the inorganic acid is selected from at least one of hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, boric acid, and phosphoric acid, preferably hydrochloric acid and / or sulfuric acid; Preferably, the organic acid is selected from at least one of acetic acid, citric acid, formic acid, and oxalic acid.

9. An oil-containing exhaust gas treatment method, characterized by, The method is carried out in the oil-containing tail gas treatment device according to any one of claims 1-9, comprising: The oil-containing tail gas enters the containing cavity from the tail gas inlet (8), and is treated by contacting the porous material (7) in the adsorption assembly from bottom to top, and the treated tail gas is discharged through the tail gas outlet (9).

10. The method according to claim 9, wherein, The oil-containing tail gas contains non-methane hydrocarbon compounds, and the rest is N2, preferably the content of non-methane hydrocarbon compounds in the oil-containing tail gas is less than 10000 ppm, and is not 0 ppm; Preferably, the conditions of the contacting treatment comprise a temperature of room temperature and / or a gas hourly space velocity of the oil-containing off-gas of 1000-50000 h -1 ; And / or The oil-containing tail gas contains 0.1-1% benzene series by volume; the content of C2-C5 hydrocarbons is less than 0.1% by volume, and the rest is air.

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