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CN-121971944-A - Chemical tail gas treatment process based on microwave pyrolysis

CN121971944ACN 121971944 ACN121971944 ACN 121971944ACN-121971944-A

Abstract

The invention discloses a chemical tail gas treatment process based on microwave pyrolysis, belongs to the technical field of chemical tail gas treatment, and is used for solving the technical problems that the purification rate of VOCs and the purification rate of malodorous pollutants in the chemical tail gas microwave pyrolysis process in the prior art are to be further improved; the invention adopts a three-section combined structure of microwave absorbing multiphase foam ceramic particles, oxygen storage perovskite honeycomb blocks and B-N-P co-doped porous carbon powder body to construct a continuous reaction system from front-end cracking, middle-section atmosphere steady state regulation and control to tail-end deep reforming, and each section of materials form step synergy in the aspects of energy absorption, redox balance and residual component reforming, so that pollutants can realize a complete conversion path from coarse cracking, redistribution to fine polishing, and the synergistic system can obviously improve the stability, the deep treatment capability and the adaptability to various complex tail gases in the whole purification process, thereby realizing excellent comprehensive purification effects.

Inventors

  • SHI TIELIU

Assignees

  • 上海云捷信智能科技有限公司

Dates

Publication Date
20260505
Application Date
20260305

Claims (10)

  1. 1. The chemical tail gas treatment process based on microwave pyrolysis is characterized by comprising the following steps of: S1, mixing organic waste gas, air and nitrogen in a gas mixing pipeline to obtain mixed waste gas; S2, sequentially introducing the mixed waste gas into a microwave cracking reactor filled with microwave absorbing multiphase foam ceramic particles, oxygen storage perovskite honeycomb blocks and B-N-P co-doped porous carbon powder, and carrying out cracking and purifying treatment under the conditions of set microwave power and temperature to obtain outlet purified gas; and S3, sequentially introducing the outlet purified gas into a heat exchanger and an alkaline washing tower for heat exchange and washing treatment to obtain purified tail gas.
  2. 2. The chemical tail gas treatment process based on microwave pyrolysis according to claim 1, wherein in the step S1, the flow ratio of organic waste gas, air and nitrogen is 80-120:20-25:10, the dosage ratio of multiphase foamed ceramic particles, oxygen storage perovskite honeycomb blocks and B-N-P co-doped porous carbon powder is 10-12:6-9:4-6, the inlet pressure of a microwave pyrolysis reactor is-200 Pa, the microwave power is 4-6kW, the bed operating temperatures of the microwave absorbing multiphase foamed ceramic particles, the oxygen storage perovskite honeycomb blocks and the B-N-P co-doped porous carbon powder are 650-750 ℃, 600-700 ℃ and 400-500 ℃, and the gas residence time is 0.5-0.8S, 0.4-0.6S and 0.8-1.0S, respectively.
  3. 3. The chemical tail gas treatment process based on microwave pyrolysis according to claim 1, wherein the microwave absorbing multiphase foam ceramic particles are prepared by the following method: A1, adding aluminum-iron doped silicon-based sponge gel particles into a muffle furnace, heating to 300-320 ℃ in an air atmosphere, carrying out heat preservation treatment for 2-4h, cooling to 150-200 ℃ in a nitrogen atmosphere after heat preservation, and taking out to obtain microwave absorbing multiphase foam ceramic particles; A2, mixing the iron aluminum oxide-silicon skeleton foam particles and graphite powder, placing the mixture in a tube furnace, carrying out sectional heat treatment, and cooling to obtain the microwave absorbing multiphase foam ceramic particles.
  4. 4. The chemical tail gas treatment process based on microwave pyrolysis according to claim 3, wherein in the step A1, the heating rate is 2-3 ℃ per minute, and in the step A2, the dosage ratio of the iron aluminum oxide-silicon skeleton foam particles to the graphite powder is 10-12g:3-5g.
  5. 5. The chemical tail gas treatment process based on microwave pyrolysis according to claim 3, wherein the preparation method of the aluminum-iron doped silicon-based sponge gel particles is characterized in that tetraethoxysilane and absolute ethyl alcohol are added into a reaction kettle to be stirred, deionized water, 1-2wt% nitric acid aqueous solution, 8-12wt% polyvinyl alcohol aqueous solution, 8-12wt% citric acid aqueous solution, 1.5mol/L aluminum nitrate aqueous solution and 1.5mol/L nitric acid aqueous solution are sequentially added after being uniformly mixed, the mixture is continuously stirred until the system is uniform, then the mixture is poured into a die, and after standing aging for 16-24 hours at room temperature, the aluminum-iron doped silicon-based sponge gel particles are obtained after post treatment.
  6. 6. The process for treating chemical tail gas based on microwave pyrolysis according to claim 5, wherein in the process of preparing the aluminum-iron doped silicon-based sponge gel particles, the dosage ratio of tetraethoxysilane, absolute ethyl alcohol, deionized water, 1-2wt% nitric acid aqueous solution, 8-12wt% polyvinyl alcohol aqueous solution, 8-12wt% citric acid aqueous solution, 1.5mol/L aluminum nitrate aqueous solution and 1.5mol/L ferric nitrate aqueous solution is 25-30mL:100mL:40mL:1mL:20-25mL:8-12mL:6mL:3-5mL.
  7. 7. The chemical tail gas treatment process based on microwave pyrolysis according to claim 1, wherein the oxygen storage perovskite honeycomb block is prepared by the following method: Adding lanthanum nitrate, strontium nitrate, cobalt nitrate, ferric nitrate and deionized water into a reaction kettle, stirring, adding citric acid and ethylene glycol after uniformly mixing, heating the reaction kettle to 80-90 ℃, keeping the temperature, stirring for 2 hours to obtain a gel material, and performing post-treatment to obtain perovskite powder; and B2, mixing perovskite powder, an inorganic binder and deionized water to obtain a plastic paste, and performing aftertreatment to obtain the oxygen storage perovskite honeycomb block.
  8. 8. The chemical tail gas treatment process based on microwave pyrolysis according to claim 7, wherein in the step B1, the dosage ratio of lanthanum nitrate, strontium nitrate, cobalt nitrate, ferric nitrate, deionized water, citric acid and ethylene glycol is 6-8g to 3g to 2-3g to 2g to 6-9g to 30mL to 60-80mL, and in the step B2, the dosage ratio of perovskite powder, inorganic binder and deionized water is 25-30g to 7-9g to 12-15mL, wherein the inorganic binder is silica sol.
  9. 9. The chemical tail gas treatment process based on microwave pyrolysis according to claim 1, wherein the preparation method of the B-N-P co-doped porous carbon powder body is characterized in that melamine, urea, boric acid, 80-90wt% of phosphoric acid aqueous solution and potassium hydroxide are ground uniformly, then are put into a crucible, are placed into a tube furnace, are protected by nitrogen, are heated to 900-950 ℃ at a heating rate of 3-5 ℃ per minute, are kept for 1-2 hours, and are post-treated to obtain the B-N-P co-doped porous carbon powder body.
  10. 10. The chemical tail gas treatment process based on microwave pyrolysis according to claim 9, wherein in the process of preparing the B-N-P co-doped porous carbon powder body, the dosage ratio of melamine, urea, boric acid, 80-90wt% of phosphoric acid aqueous solution and potassium hydroxide is 8-10g:12-15g:1g:5-7mL:6-8g.

Description

Chemical tail gas treatment process based on microwave pyrolysis Technical Field The invention relates to the technical field of chemical tail gas treatment, in particular to a chemical tail gas treatment process based on microwave pyrolysis. Background Microwave pyrolysis is an important physical and chemical treatment means in the field of chemical tail gas treatment in recent years, and is based on the selective energy coupling characteristics of electromagnetic waves on polar gas molecules, impurity clusters and solid-phase media, and by exciting molecular rotation, vibration and local high-energy states, bond energy weakening and chain segment breaking of macromolecular pollutants are promoted, so that rapid pyrolysis and conversion are realized, the process is generally developed around microwave field distribution, medium absorption characteristics and gas-solid reaction interface behaviors to form a stable high-energy density region and drive initiation and deep conversion of complex components, and in engineering application, microwave pyrolysis technology has been used for treating multiple types of tail gases containing volatile organic matters (VOCs), halogen-containing gases, sulfur-containing and nitrogen-containing inorganic matters, and the like, and research focuses on dielectric property design of microwave absorption materials, field intensity homogenization regulation and control of reactor cavities and dynamic evolution rules of free radicals and short-chain species in the pyrolysis process, so that an expandable technical foundation is provided for efficiently treating tail gases with large component fluctuation and complex conversion paths in the chemical industry. The existing microwave pyrolysis tail gas treatment process generally has the problems of uneven energy field distribution and insufficient local absorption efficiency, so that conditions of incomplete pyrolysis, limited bond breaking rate and the like of aromatic and halogenated organic matters often occur in an initial stage, the proportion of convertible active fragments in a subsequent reaction chain is lower, and in addition, the existing process often lacks effective atmosphere buffering and oxygen amount adjusting means due to changeable pyrolysis product structure and high reaction activity, and an intermediate is easy to generate uncontrolled side reaction in the transmission process, so that the overall reaction stability of the system is insufficient, and the method is difficult to adapt to the fluctuation input of multi-component tail gas. The other traditional process focuses on treating the cracked residual components by a single adsorption or carbon-based catalysis mode, but under a complex atmosphere with high temperature and multiple hetero atoms, the active sites of the materials are often attenuated due to the change of oxygen content or the increase of reaction load, so that the treatment capacity of the tail end on ammonia, sulfhydryl and refractory fragments is limited, and meanwhile, the capture efficiency and the deep conversion capacity of pollutants entering the tail end materials are easily influenced because the pollutants enter the tail end materials are not subjected to sufficient structural pretreatment, so that the whole purification path has the characteristics of discontinuity and incompleteness, and the stable and comprehensive treatment on the mixed tail gas is difficult to realize. In view of the technical drawbacks of this aspect, a solution is now proposed. Disclosure of Invention The invention aims to provide a chemical tail gas treatment process based on microwave pyrolysis, which is used for solving the technical problems that the purification rate of VOCs and the purification rate of malodorous pollutants in the chemical tail gas microwave pyrolysis process in the prior art are to be further improved. The aim of the invention can be achieved by the following technical scheme: a chemical tail gas treatment process based on microwave pyrolysis comprises the following steps: S1, mixing organic waste gas, air and nitrogen in a gas mixing pipeline to obtain mixed waste gas; S2, sequentially introducing the mixed waste gas into a microwave cracking reactor filled with microwave absorbing multiphase foam ceramic particles, oxygen storage perovskite honeycomb blocks and B-N-P co-doped porous carbon powder, and carrying out cracking and purifying treatment under the conditions of set microwave power and temperature to obtain outlet purified gas; and S3, sequentially introducing the outlet purified gas into a heat exchanger and an alkaline washing tower for heat exchange and washing treatment to obtain purified tail gas. The reaction principle for preparing the purified tail gas is as follows: Organic waste gas is fed into a microwave field after passing through a mixed system, gas phase molecules are rapidly excited under the action of electromagnetic energy, so that partial functional grou