Active carbon homogenizing agent for petrochemical tail gas treatment device and preparation method thereof

Abstract

The application discloses a kind of activated carbon homogenizing agent for petrochemical tail gas treatment device and its preparation method and application, belong to petrochemical tail gas environmental protection processing technical field.The activated carbon homogenizing agent is prepared by high iodine value activated carbon base material with iodine value ≥800mg / g and 5% mass concentration sodium hydroxide modification liquid according to 1000kg∶100L dosage ratio, after uniform infiltration by low-pressure atomization spraying, preparation is made into at room temperature airtight static curing 5 hours.The application builds alkaline adsorption site inside activated carbon pore, so that material has three functions of airflow homogenization, concentration buffer and acidic impurity pre-removal.The preparation process is simple, no three wastes are generated, and is suitable for industrial production.The application effectively solves the technical problems of large petrochemical tail gas concentration fluctuation, sulfide corrosion catalyst and single function of conventional homogenizing material, and is suitable for VOCs tail gas and sulfur-containing tail gas pretreatment homogenization adjustment generated in petroleum refining, catalytic cracking, hydrogenation device and the like.

Description

Technical Field

[0001] This invention relates to the field of petrochemical tail gas environmental protection treatment technology, specifically to an activated carbon homogenizer for petrochemical tail gas treatment devices and its preparation method. Background Technology

[0002] In the petrochemical production process, catalytic cracking units, hydrogenation units, distillation units, and storage and transportation units continuously generate large amounts of complex tail gas, which contains fluctuating VOCs, trace amounts of sulfides, oil and gas aerosols, dust impurities, etc. Petrochemical tail gas is characterized by large concentration fluctuations, turbulent gas flow, local concentration enrichment, and uneven composition.

[0003] Currently, exhaust gas treatment devices in the industry generally suffer from the following defects: 1. Large fluctuations in exhaust gas concentration can easily lead to unstable equipment operation. Fluctuations in the inlet exhaust gas concentration, with instantaneous high concentrations of waste gas directly entering the RTO and catalytic oxidation equipment, can easily cause equipment overheating, catalyst poisoning, incomplete combustion, and the generation of secondary pollutants. Research results show that activated carbon adsorbents can effectively buffer fluctuations in the concentration load of volatile organic compounds (VOCs).

[0004] 2. Conventional homogenization materials have limited functionality. Conventional porous ceramic homogenization plates and metal homogenization meshes can only adjust airflow velocity and do not have the ability to adsorb components, buffer concentrations, or pretreat impurities, thus failing to solve the problem of localized enrichment of VOCs and sulfides.

[0005] 3. Ordinary activated carbon has poor selectivity and short service life. Ordinary activated carbon has not undergone alkaline modification, so it has poor adsorption selectivity for petrochemical acidic sulfur-containing tail gas and polar organic waste gas. Its pores are easily blocked quickly, resulting in a short service life and poor homogenization and stabilization effects.

[0006] 4. Commercially available homogenizing materials have poor compatibility. These materials cannot meet the complex and harsh operating conditions of petrochemical plants, which are characterized by high humidity, oil content, and sulfur content, resulting in low operational stability and high maintenance costs for exhaust gas treatment equipment. Summary of the Invention

[0007] This invention aims to overcome the shortcomings of existing technologies, such as single-mode tail gas homogenization, poor sulfur resistance, weak concentration buffering capacity, and poor adaptability to operating conditions. It provides an activated carbon homogenizer for petrochemical tail gas treatment devices and its preparation method. This invention utilizes high-iodine-value activated carbon modified by low-concentration sodium hydroxide spraying. While retaining the ultra-high specific surface area and pore buffering advantages of activated carbon, it imparts alkaline adsorption sites to the material, effectively achieving homogenization of petrochemical tail gas flow, concentration balance, and pre-removal of acidic impurities, significantly improving the operational stability of downstream tail gas treatment equipment.

[0008] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution: An activated carbon homogenizer for a petrochemical tail gas treatment device is prepared by mixing and impregnating a high-iodine-value activated carbon substrate with a sodium hydroxide modified liquid. The activated carbon homogenizer is used at the inlet of the petrochemical tail gas treatment device to homogenize the concentration, condition the airflow, and pre-adsorb impurities in the refining tail gas containing VOCs, sulfur, and dust.

[0009] As a preferred embodiment of the activated carbon homogenizing agent for petrochemical tail gas treatment device described in this invention, the iodine value of the high iodine value activated carbon substrate is ≥800mg / g, and the activated carbon is granular coal-based activated carbon or fruit shell activated carbon.

[0010] As a preferred embodiment of the activated carbon homogenizing agent for a petrochemical tail gas treatment device according to the present invention, the sodium hydroxide modified liquid is a 5% (w / w) sodium hydroxide aqueous solution.

[0011] As a preferred embodiment of the activated carbon homogenizing agent for a petrochemical tail gas treatment device according to the present invention, the ratio of the high iodine value activated carbon substrate to the sodium hydroxide modified liquid is 1000 kg: 100 L.

[0012] A method for preparing the activated carbon homogenizing agent for the above-mentioned petrochemical tail gas treatment device includes the following steps: S1. Select activated carbon with an iodine value ≥800mg / g as the base material and prepare it quantitatively; S2. Prepare a 5% sodium hydroxide aqueous solution as the modified wetting solution; S3. Take the modified impregnation liquid and spray it evenly onto the surface of the activated carbon substrate using a low-pressure atomization spraying method, so that the modified liquid evenly impregnates the activated carbon substrate. S4. The sprayed activated carbon is left to stand at room temperature in a sealed environment to mature, so that the modified liquid can fully penetrate the pores of the activated carbon, thereby obtaining the activated carbon homogenizer.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses high-porosity activated carbon with an iodine value ≥800 as the base material. The multi-level interconnected pores can break up the turbulent structure of the exhaust gas and balance the airflow velocity. At the same time, it utilizes the adsorption and slow release characteristics of pores to adsorb and buffer instantaneous high concentrations of VOCs and oil and gas, and slowly releases them during low concentration periods, thus completely solving the industry problem of large fluctuations in the concentration of petrochemical exhaust gas.

[0014] By modifying the activated carbon with 5% sodium hydroxide at low temperature, alkaline adsorption sites are constructed inside the pores of the activated carbon. This allows for targeted adsorption and neutralization of acidic sulfur-containing impurities such as hydrogen sulfide and mercaptans in the exhaust gas, preventing sulfides from entering downstream equipment and causing catalyst poisoning and equipment corrosion, thus significantly improving the exhaust gas system's anti-pollution capability.

[0015] This invention uses only room temperature atomization spraying and natural curing processes, without the need for high-temperature roasting or complex compound raw materials. It has low equipment requirements, is easy to operate, and generates no waste. It can process tons of materials in a single batch, making it very suitable for large-scale application in petrochemical and environmental protection enterprises.

[0016] The material of this invention can significantly improve the uniformity of exhaust gas inlet concentration, prevent instantaneous high concentration exhaust gas from impacting the RTO furnace body, avoid the risks of overheating, flameout, and deflagration, stabilize the operating parameters of the exhaust gas treatment system, and reduce equipment failure rate and maintenance costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a flowchart illustrating the preparation process of an activated carbon homogenizing agent for a petrochemical tail gas treatment device according to the present invention. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Example 1

[0019] A method for preparing activated carbon homogenizing agent for petrochemical tail gas treatment equipment, comprising the following steps: (1) Select granular coal-based activated carbon with an iodine value of 820 mg / g and accurately weigh 1000 kg as the base material for later use; (2) Prepare a 5% sodium hydroxide aqueous solution at room temperature and stir until there is no precipitate; (3) Take 100L of 5% sodium hydroxide aqueous solution and spray it evenly on the surface of activated carbon material using a low-pressure atomizing spraying device. Turn the material over throughout the process to ensure that each piece of activated carbon is evenly wetted. (4) The sprayed activated carbon material is sealed and piled up, and left to stand at room temperature for 5 hours to allow the alkaline solution to fully penetrate the micropores and complete the surface modification, and finally obtain the petrochemical tail gas special activated carbon homogenizer. Example 2

[0020] A method for preparing activated carbon homogenizing agent for petrochemical tail gas treatment equipment, comprising the following steps: (1) Select granular fruit shell activated carbon with an iodine value of 850 mg / g and accurately weigh 1000 kg as the base material for later use. (2) Prepare a 5% sodium hydroxide aqueous solution at room temperature and stir until there is no precipitate; (3) Take 100L of 5% sodium hydroxide aqueous solution and spray it evenly on the surface of activated carbon material in three times using a low-pressure atomizing spraying device. Turn the material over for 5 minutes after each spraying to ensure that each piece of activated carbon is evenly wetted. (4) The sprayed activated carbon material is sealed and piled up, and left to stand at room temperature for 5 hours to allow the alkaline solution to fully penetrate the micropores and complete the surface modification, and finally obtain the petrochemical tail gas special activated carbon homogenizer. Example 3

[0021] A method for preparing activated carbon homogenizing agent for petrochemical tail gas treatment equipment, comprising the following steps: (1) Select granular coal-based activated carbon with an iodine value of 800 mg / g and accurately weigh 1000 kg as the base material for later use; (2) Prepare a 5% sodium hydroxide aqueous solution at room temperature and stir until there is no precipitate; (3) Take 100L of 5% sodium hydroxide aqueous solution and spray it evenly on the surface of activated carbon material using a low-pressure atomizing spraying device. During the spraying process, continuously turn the material to ensure that each piece of activated carbon is evenly wetted. (4) The sprayed activated carbon material is sealed and piled up, and left to stand at room temperature for 5 hours to allow the alkaline solution to fully penetrate the micropores and complete the surface modification, and finally obtain the petrochemical tail gas special activated carbon homogenizer.

[0022] Application test cases The homogenizing agent prepared in Example 1 was filled into the inlet homogenization chamber of a catalytic cracking tail gas RTO unit in a refinery, and the data were monitored after 30 days of continuous operation: (1) The fluctuation range of exhaust gas inlet concentration is reduced by more than 85%, and there is no local high-concentration gas cloud enrichment phenomenon. (2) The exhaust gas flow velocity is uniform and stable, and turbulence is completely eliminated; (3) The pre-removal rate of trace sulfides in the exhaust gas is ≥35%, which effectively protects the downstream catalyst; (4) The RTO equipment has no over-temperature or fluctuation alarms, and the equipment operation stability is significantly improved.

[0023] Comparative experimental cases To verify the modification effect of the activated carbon homogenizer of the present invention, unmodified activated carbon (iodine value 820 mg / g, without sodium hydroxide treatment) was used as the control group, and the activated carbon homogenizer prepared in Example 1 was used as the experimental group. Comparative tests were conducted under the same working conditions, and the results are shown in Table 1.

[0024] Table 1 Comparison of homogenization properties of activated carbon before and after modification Reduction rate of exhaust gas concentration fluctuation (%) 52.3 85.6 +63.7% Sulfide pre-removal rate (%) 12.7 36.4 +186.6% Iodine retention rate (%) after 30 days of continuous operation 68.5 89.2 +30.2% Airflow homogenization uniformity (dimensionless) 0.71 0.93 +31.0% Results Analysis: After modification by low-temperature spraying with sodium hydroxide, the performance indicators of the activated carbon homogenizer of this invention are significantly better than those of unmodified activated carbon. Specifically, the reduction rate of tail gas concentration fluctuation increased from 52.3% to 85.6%, an increase of 63.7%; the pre-removal rate of sulfides increased from 12.7% to 36.4%, an increase of 186.6%; and the iodine value retention rate after 30 days of continuous operation increased from 68.5% to 89.2%, indicating that the homogenizer of this invention has a longer service life. Experimental results show that low-temperature spraying modification with 5% sodium hydroxide effectively constructs alkaline adsorption sites inside the pores of activated carbon, significantly improving the material's adsorption capacity for acidic sulfur-containing impurities and its anti-pollution ability.

[0025] Process parameter optimization experiment To verify the rationality of the optimal process parameters (concentration of modified solution and aging time) of the present invention, coal-based activated carbon with an iodine value of 820 mg / g was used as the base material. Comparative experiments were conducted with different concentrations of modified solution and different aging times. The pre-removal rate of sulfides and the retention rate of iodine value were used as evaluation indicators. The results are shown in Table 2.

[0026] Table 2. Effects of different process parameters on the performance of homogenizing agents Comparative Example 1 1 5 18.2 92.5 Comparative Example 2 3 5 25.7 91.8 Example 1 5 5 36.4 91.2 Comparative Example 3 8 5 35.8 82.6 Comparative Example 4 10 5 34.1 76.3 Comparative Example 5 5 1 18.9 93.1 Comparative Example 6 5 3 26.5 92.4 Example 1 5 5 36.4 91.2 Comparative Example 7 5 8 36.8 88.5 Comparative Example 8 5 12 37.2 84.7 Results analysis: (1) Effect of Modification Solution Concentration: When the NaOH concentration is 5%, the sulfide pre-removal rate reaches 36.4%, and the iodine value retention rate is 91.2%, exhibiting the best overall performance. At concentrations that are too low (1%, 3%), the alkaline modification is insufficient, resulting in a low sulfide pre-removal rate; at concentrations that are too high (8%, 10%), the alkalinity is too strong, causing excessive etching of the activated carbon pore structure, significantly reducing the iodine value retention rate, and without further improving the sulfide pre-removal rate. The results indicate that 5% NaOH is the optimal modification concentration.

[0027] (2) Effect of curing time: When the curing time is 5 hours, the pre-removal rate of sulfides reaches 36.4%, and the iodine retention rate is 91.2%, showing the best overall performance. When the curing time is too short (1h, 3h), the modified solution fails to fully penetrate the pores of activated carbon, and the construction of alkaline sites is insufficient; when the curing time is too long (8h, 12h), the alkaline solution excessively corrodes the microporous structure of activated carbon, and the iodine retention rate decreases. The results indicate that 5 hours is the optimal curing time.

[0028] The above examples and experimental data show that the activated carbon homogenizer prepared by the present invention through low-temperature spraying modification with high iodine value activated carbon (≥800mg / g) and 5% sodium hydroxide exhibits excellent performance in tail gas concentration homogenization, airflow conditioning, and impurity pre-adsorption. After modification by the present invention, the tail gas concentration fluctuation reduction rate reaches more than 85%, and the sulfide pre-removal rate is ≥35%, both significantly better than that of unmodified activated carbon. The process parameters of the present invention (5% NaOH concentration, 5-hour aging time) have been experimentally verified to be the optimal ratio; too low or too high a ratio will affect the overall performance of the homogenizer. The preparation process of the present invention is simple, generates no waste, is suitable for industrial mass production, and has broad prospects for promotion and application.

[0029] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An activated carbon homogenizing agent for a petrochemical tail gas treatment device, characterized in that, It is prepared by mixing and impregnating a high-iodine-value activated carbon substrate with a sodium hydroxide modified liquid; the activated carbon homogenizer is used at the inlet of a petrochemical tail gas treatment device to homogenize the concentration, condition the airflow, and pre-adsorb impurities in the refining tail gas containing VOCs, sulfur, and dust.

2. The activated carbon homogenizing agent for petrochemical tail gas treatment device according to claim 1, characterized in that, The iodine value of the high iodine value activated carbon substrate is ≥800mg / g, and the activated carbon is granular coal-based activated carbon or fruit shell activated carbon.

3. The activated carbon homogenizing agent for petrochemical tail gas treatment device according to claim 1, characterized in that, The sodium hydroxide modified solution is a 5% (w / w) sodium hydroxide aqueous solution.

4. The activated carbon homogenizing agent for petrochemical tail gas treatment device according to claim 1, characterized in that, The ratio of the high iodine value activated carbon substrate to the sodium hydroxide modified solution is 1000 kg: 100 L.

5. A method for preparing an activated carbon homogenizing agent for a petrochemical tail gas treatment device as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Select activated carbon with an iodine value ≥800mg / g as the base material and prepare it quantitatively; S2. Prepare a 5% sodium hydroxide aqueous solution as the modified wetting solution; S3. Take the modified impregnation liquid and spray it evenly onto the surface of the activated carbon substrate using a low-pressure atomization spraying method, so that the modified liquid evenly impregnates the activated carbon substrate. S4. The sprayed activated carbon is left to stand at room temperature in a sealed environment to mature, so that the modified liquid can fully penetrate the pores of the activated carbon, thereby obtaining the activated carbon homogenizer.

6. The preparation method according to claim 5, characterized in that, The activated carbon substrate in step S1 has an iodine value of 820 mg / g and a quantitative preparation amount of 1000 kg; the modified impregnation solution in step S3 is used in an amount of 100 L.

7. The preparation method according to claim 5, characterized in that, The mass concentration of the sodium hydroxide aqueous solution in step S2 is 5%.

8. The preparation method according to claim 5, characterized in that, The time for room temperature sealed aging in step S4 is 5 hours.

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