Odor gas treatment technology
air purification technology:
with the rapid development of petrochemical industry and organic synthesis industry, a large number of organic and inorganic waste gases are also discharged into the atmosphere, which has a serious impact on the environment, especially the gas with odor. Developed countries have paid attention to the research on odor gas pollution since the 1950s, and formulated a series of regulations, such as the determination and evaluation of odor gas, and the control of old factories with a history of several decades or even hundreds of years. China promulgated gb14554-93 in 1993 (emission standard of odor pollutants) has formulated the emission concentration limits of odor pollutants such as ammonia, trimethylamine, hydrogen sulfide, methyl mercaptan, methyl sulfide, dimethyl disulfide, carbon disulfide, styrene, etc.
odor gas not only has a serious impact on the ecological environment, but also has great harm to human health, causing central nervous system disorders, diseases, chronic diseases, acute diseases and deaths. Odor substances are through odorant groups , such as sulfur group and carboxyl group, stimulate olfactory cells and make people feel disgusted and unhappy. Odor gas has many pollution sources, a wide range of pollution, involving many industries, generally low concentration, complex components, and difficult monitoring. Governance difficulties
the concentration of odor gas is low, and the odor gas concentration required after treatment is lower, which makes the treatment of odor gas pollution different from the treatment of general air pollution. As early as the late 1950s, foreign countries began to study the treatment of odor gas pollution, and accumulated rich theoretical knowledge and practical experience. In China, the investigation, testing and standard research of odor gas pollution were carried out only in the 1980s, while the research on deodorization technology was carried out only in the 1990s
the purpose of various odor gas treatment methods is to change the material structure of odor gas and eliminate odor through physical, chemical and biological effects. Common treatment methods of odor gas include combustion method, oxidation method, absorption method, adsorption method, neutralization method and biological method. See Table 1 for its definition, scope of application and characteristics. Table 1 Comparison of common odor gas treatment methods
definition of treatment methods scope of application characteristics combustion method degrades combustible odor substances through strong oxidation reaction. The method is suitable for the treatment of combustible odor substances with high concentration and small gas volume. The decomposition efficiency is high, but the equipment is easy to corrode, consumes fuel, and has high cost. Secondary pollutants may be generated in the treatment. Oxidation method uses oxidants to oxidize odor substances is suitable for medium and small The treatment efficiency of low concentration odor gas is high, but oxidant is required, and the treatment cost is high. The absorption method uses solvent to absorb the odor substances in the odor and deodorize the gas. The method is suitable for the treatment of high and medium concentration odor gas. The flow is large, and the process is mature, but the treatment efficiency is not high, and the absorbent is consumed, Pollutants are only transferred from the gas phase to the liquid phase adsorption method. The method of removing odorous substances in odorous gas by adsorbent adsorption is applicable to odorous gas with low concentration and high purification requirements. It can deal with odorous gas with multiple components. The treatment efficiency neutralization method uses neutralization deodorizer to weaken the odor sensory intensity. The method is applicable to occasions that need to immediately and temporarily eliminate the impact of odorous gas with low concentration. It can quickly eliminate the impact of odorous gas with great flexibility, However, odorous gas substances have not been removed, and neutralizers need to be added. The biological method uses microorganisms to degrade odorous substances to make the gas deodorize. It is suitable for the removal of biodegradable water-soluble odorous substances. The removal efficiency is high, the treatment device is simple, the treatment cost is low, the operation and maintenance is easy, and secondary pollution can be avoided.
the odor gas treatment methods listed in the above table have their own advantages and disadvantages, Which treatment method is more suitable depends on the specific factors such as the nature, concentration, treatment capacity, local health requirements and economic conditions of odor substances. In practice, several methods are often used in combination. Biological law, developed in the 1950s, has developed rapidly because of its significant advantages, especially in Japan, Germany, the Netherlands and other countries. China began to study this aspect in the late 1980s. In recent years, people pay more and more attention to the treatment of odor gas, and the focus of research has shifted to the study of biological methods
odor 1. Automatic calibration: the system can automatically calibrate the accuracy of indication; The principle of biological deodorization of gas: under the conditions of water and the presence of microorganisms and oxygen, Hunan Academy of Forestry Sciences uses the metabolism of microorganisms to oxidize and decompose odorous substances, so as to achieve the purpose of purifying gas. Biological treatment can be roughly divided into three processes: odorous substances are adsorbed by carriers (fixed with microorganisms); Odorous substances diffuse to the surface of microorganisms and are adsorbed by microorganisms; Microorganisms oxidize and decompose odorous substances. Odorous substances without nitrogen are decomposed into CO and H2O, odorous substances with sulfur are decomposed into s, so32-, so42-, and odorous substances with nitrogen are decomposed into nh4+, no2-, no3-
biological treatment of odor gas mainly includes biofilter, trickling biofilter and biological scrubber. At present, biofilter and trickling biofilter are the most widely used. See Table 2 for the comparison of three main biological treatment methods. Table 2 Comparison of three main biological treatment methods
characteristics of treatment methods advantages and disadvantages scope of application biological filter single reactor, microbial and liquid-phase fixed gas/liquid surface area ratio is high, the equipment is simple, the operation cost is low, the reaction conditions are difficult to control, the change of intake air concentration should be slow, and the floor area is large, which is suitable for the treatment of chemical fertilizer plants Sewage treatment plant and industrial and agricultural waste gas biological scrubber with mass concentration of malodor between 0.5 ~ 1.0g/m3. Microorganisms are suspended in liquid. Liquid phase flow equipment is compact, low pressure loss, reaction conditions are easy to control, mass transfer surface area is small, a large amount of oxygen supply is required to maintain high degradation efficiency, and excess sludge needs to be treated, High investment and operation costs are applicable to the treatment of industrial waste gas with a mass concentration of malodorous substances ranging from 1 to 5g/m3. The biological trickling filter is a single reactor with fixed microorganisms and liquid phase flow. Compared with the biological washing tower, the equipment is simple and the mass transfer surface area is small. It needs to deal with excess sludge. High operation costs are applicable to the treatment of chemical fertilizer plants The biological treatment technology of odor gas with the mass concentration of pollutants less than 0.5g/m3 produced by sewage treatment plants and agriculture has incomparable advantages over other traditional methods, such as high treatment efficiency, no secondary pollution, simple equipment, easy operation, low cost, convenient management and maintenance, which has been paid more and more attention by countries and widely used in Europe and the United States. In recent years, many scientific researchers in China have carried out research on biological treatment of odor gas, and have achieved some research results
however, because the bioreactor involves gas, liquid and solid three-phase mass transfer and biochemical degradation processes, there are many and complex influencing factors, so there are still many problems to be solved in theoretical research and practical application. The future research should mainly focus on: (1) the biological treatment of low concentration and complex mixed odor gas needs to be studied; (2) Bacterial species suitable for specific organic matter degradation our company sincerely welcomes our factory to visit the research and development of guidance and inoculation methods; (3) Research on the dynamics and biological principles of biological treatment of waste gas; (4) Combined with other odor gas treatment methods to improve the removal effect of odor substances; (5) Development of new and efficient biological treatment equipment. (end)