The "pain point" of exhaust gas treatment - the treatment process cat tired exposure

China Paint Online News Information
In the process of the development of China's industry and manufacturing industry, the increasingly serious issue of ecological environment protection has been widely concerned by the community, in order to resolutely implement the "adherence to the harmonious coexistence of man and nature, the construction of ecological civilization is the sustainable development of the Chinese nation's millennium plan" development strategy. Governments at all levels have also made environmental control and pollution control one of the government's priorities, and the country has set off a wave of ecological environment protection. The treatment of volatile organic emissions (VOCs) has also become a major environmental protection implementation work, for this reason, the relevant departments do not hesitate to shut down some pollution-related production enterprises. To promote the production enterprises to increase the VOCs emission standards of environmental protection facilities. But the current situation of VOCs compliance emissions treatment (VOCs processing) is still in disarray, which has led to the tragic consequences of companies spending money on "handcuffs".the main reason is that some VOCs treatment in the lack of quantitative analysis, no treatment of pollutants under the premise of taking a big copy of the world article, buy a few equipment assembly on the completion of VOCs treatment, it is conceivable that the result is not only did not effectively treat harmful substances, but also discharged new pollutants into the atmosphere. Such as Guangdong VOCs control high prevalence of a city, in air pollution (ozone) testing even many times exceeded the standard, retrospectively the main reason is that many production enterprises VOCs treatment equipment not only failed to eliminate pollutants, but also produced new pollutants, such as "the devil on the ground" ozone.。 VOCs mainly include carbon hydrocarbon compounds, benzene and benzene, alcohols, ketones, phenols, aldehydes, esters, amines, acrylics, cyanide and other organic compounds. From electronics, chemicals, petrochemicals, coatings, printing, coating, furniture, leather and other industries production process.。 VOCs are one of the sources of air pollution, one of the causes of air pollution problems such as haze and photochemical smog, and one of the main causes of regional composite atmospheric pollutants characterized by PM2.5. VOCs through the respiratory tract and skin into the human body, may give people breathing, blood, liver and other systems and organs caused temporary and permanent lesions, especially benzenetypes of polycyclic aromatic hydrocarbons can directly cause cancer, VOCs on human health is extremely harmful.Now on some production enterprises to apply VOCs treatment technology and its effects related analysis: 1, activated carbon adsorption method 1 pollution principle activated carbon adsorption method due to low prior investment, is currently the most used VOCs treatment method, is the natural adsorption capacity of activated carbon adsorption VOCs, when adsorption saturation saturation, activated carbon desorption regeneration or to professional waste companies to deal with.2 Practical application the use of activated carbon adsorption method for VOCs treatment of environmental protection companies on their equipment de-fouling parameters, basically will mention that the de-fouling efficiency of such equipment reached more than 90%, but in the actual de-fouling application process, the de-fouling efficiency of more than 90% is only theoretical value. And in different working environments, its de-fouling efficiency is much lower than the theoretical value. The main causes include temperature, working environment humidity, water mist, acidity, dust and the interaction between adsorbed gases. For example, the year-round humidity in southern China is larger, the temperature is higher, and the actual adsorption of activated carbon is less than 50% of the laboratory.3 main problem the use of activated carbon adsorption method to deal with VOCs emissions actual operation and maintenance costs are very high, at the same time, natural suction, desorption management difficulties, applicability is affected by a variety of factors, not suitable for dust, water vapor, milk and other exhaust gas treatment, difficult to stabilize environmental protection standards. And a large number of saturated activated carbon treatment is more expensive, the method is only to absorb pollutants transfer, such as the saturated activated carbon transfer process without strict control tracking, it is very easy to cause secondary pollution. However, due to the early investment is less, the enterprise natural selection more, although the supervision is difficult (carbon box no activated carbon, activated carbon facilities are too simple, almost do not change carbon, activated carbon selection and the actual design does not match, the use of too little, etc.), but the environmental protection department will eventually have some action, there is a huge environmental risk. And easy to fake to deal with environmental management. (e.g. there is no activated carbon in the carbon box, activated carbon facilities are too simple, almost do not change carbon, activated carbon actual engineering and design does not match, the use of too little and so on.) 2, low temperature plasma technology 1 pollution principle the medium in the low temperature plasma exhaust gas treatment equipment blocks the discharge process, the plasma internal production is rich in very high chemical activity particles, such as electrons, ions, ozone and excitation molecules. In theory, organic exhaust gases react with these high-energy active groups, some of which are cracked and eventually converted into substances such as carbon dioxide and water, thus purifying the exhaust gases.2 practical application domestic production of low-temperature plasma technology pollution control equipment, manufacturing environmental protection companies on the equipment de-fouling parameters, basically will mention that the de-fouling efficiency of such equipment reached more than 80%. A large number of low-energy plasma equipment can be used for VOCs treatment can only be used to control smoke pollution, in the actual treatment of industrial VOCs process, this low-temperature plasma technology equipment on the degradation of organic exhaust gas is basically ineffective and will produce pollution by-products, its degradation efficiency is low, and VOCs flammability makes its safety has attracted much attention.3 Main Problem The small-power low-temperature plasma, which is now widely used, is used in the past by the kitchen industry for fume treatment, which is not suitable for VOCs treatment, and produces by-products and a large amount of ozone, which will pull the arc to ignite VOCs and other issues.because plasma technology is inefficient in treating organic exhaust gases, including aromatic compounds, in a short period of time, mainly by producing intermediate products. If the use of high-power plasma in a stable organic exhaust gas, but also in a certain period of time to have a processing effect. For VOCs exhaust gases, which are constantly discharged at high speeds, their processing efficiency is very low and many intermediate by-products are secondary, resulting in more complex VOCs components (which may be more harmful), while the equipment will produce a large amount of useless ozone when running. And the vast majority of organic exhaust gas is flammable, explosive compounds. The arc of plasma operation is very easy to detonate VOCs, the Tianjin explosion has made the community question its safety, so the technology has been banned in various places has increased day by day.Three, photocatalytic oxidation1 pollution principlephotocatalytic exhaust gas treatment equipment technology is the use of special ultraviolet band, under the action of the catalyst, oxygen catalytic generation of ozone and hydroxyl free radicals and negative oxygen ions, and then the VOCs molecule redox a treatment method.2 Practical application most of the UV photocatalytic treatment equipment used in VOCs treatment is a reference to the past deodorization technology principles, usually using double-wavelength ultraviolet tube, energy is mainly used to convert ozone, with ordinary titanium dioxide material as a catalyst, although the de-fouling efficiency is said to reach more than 80%. The UV photo-catalytic processing VOCs equipment that is actually used today is less efficient, producing large amounts of ozone and intermediate by-products under the control of non-computing technology.3 Main Issues In the application of UV photo catalytic oxidation technology, including wavelength of UV tube, photo catalytic material, reaction time, relative humidity, dust particles, etc. are the bottleneck factors to deal with VOCs success or failure. It is generally believed that photo catalytic oxidation can completely degrade VOCs to produce non-toxic harmless CO2 and H2O, etc., but in use due to the short reaction time, volatile organic matter in photo catalytic oxidation reaction will produce ketones, aldehyde and other more vicious intermediate products and a large amount of ozone.factors that have caused ozone excesses in industrial towns in recent years are the misuse of plasma and ozone-producing UV photo catalytic oxidation equipment. Since both types of equipment are technologies that attempt to dissolve industrial exhaust gases by chemical reactions after converting oxygen from the air into ozone, the efficiency of converting the resulting ozone into free-form and negative oxygen ions is extremely low due to reaction conditions, and because the reaction time is too short, most of the ozone produced by the equipment is not directly discharged by the VOCs treatment.4. Biological treatment method 1 pollution principle the use of microorganisms to digest and metabolize pollutants in the exhaust gas, in essence, is a biochemical decomposition process, it is attached to the medium of active microorganisms to absorb organic exhaust gas, pollutants into harmless water, carbon dioxide and other inorganic salts. 2 Practical application with pollutants as the food source of microorganisms, biological treatment methods include: hydrocarbon oxygen composed of various organic matter, simple organic sulphides, organic nitrides, hydrogen sulfide and ammonia and other inorganic categories. Requires small gas volume, low concentration, exhaust continuous, exhaust gas treatment container is large, although the treatment process is more environmentally friendly, but the operation and maintenance of complex, biological replenishment cumbersome and other reasons, so that biological treatment method is in vain, because of its difficult supervision, so it still abounds. 3 Main issues Poor applicability: only for specific contaminants, and biobacterics are prone to death, solubles and easily degradable contaminants are subject to certain restrictions; As well as the pressure drop of the whole filling bed and whether the filling bed is easily blocked, it is difficult to achieve automatic control, it is difficult to improve the control ability of each operating parameter, the maintenance cost is high and the fault is difficult to control, the breeding difficulty is difficult: it is difficult to screen out the advantageous strains of high-efficiency degradation of various VOCs gas, the reaction site constraint: the reaction device covers a large area and the reaction time is longer. Therefore, biological method in the application of no shortage of decoration of the situation. five combustion method 1 pollution principle combustion method is divided into heat storage combustion technology (RTO) and catalytic combustion technology (RCO). The principle is to burn at low temperatures by burning directly or adding catalysts, and to completely degrade organic exhaust gases into water and carbon dioxide by "burning". 2 practical application combustion method as the current treatment efficiency and effect of relatively ideal process, although it is relatively expensive and operating costs are not low, but has been recognized by most experts and some municipal environmental authorities, and even developed as the main treatment process. 3 main problem the temperature in the combustion chamber is generally not less than 750 degrees, or even as high as 1000 degrees, due to heat storage combustion (RTO) mode, so fuel-type nitrogen oxides are produced. Nitrogen oxides are divided into three categories according to the generation process: thermal, fast and fuel, of which fuel types account for 60%-95%. In the process of generating fuel-type NOx, organic compounds containing nitrogen or nitrogen in the air are thermally cracked to produce N, CN, HCN and other intermediate product groups, which are then oxidized into NOx. According to crude calculations, a set of 200,000 m3/h treatment of heat storage combustion equipment, its nitrogen oxide emissions are equivalent to a 35t/h coal-fired fluidized bed boiler. In the catalytic combustion (RCO) process of organic exhaust gases, due to the use of tap water as a pre-treatment of water spray, chlorine ions in water and chlorine ions brought with organic matter are highly susceptible to dioxins in the catalytic combustion chamber (200-500 degrees). The VOCs treatment equipment is free of high temperature devices used to promote the decomposition of dioxins, so the gas produced during combustion of dioxins will be directly discharged into the atmosphere. why is VOCs difficult to handle? is mainly a shortage of talent! Because of the unbalanced development of the branch disciplines of organic chemistry in China, especially the intersection and infiltration of organic chemistry and other disciplines is not enough, and the research team of organic chemistry in China is generally small in scale, and the related branch disciplines are not well developed, so it has an impact on the development of the whole discipline, and there is a tendency to shrink. In the lack of policy guidance, lack of evaluation system, resulting in organic chemistry research work no one to do, also unwilling to do. Organic chemistry itself is relatively "boring", difficult employment, resulting in many Ben, Shuo, Bo students are reluctant to choose this subject, especially in some non-hot areas: such as organic photochemistry, free-based chemistry, elemental organic chemistry and so on. Secondly, is too quick to profit, the management of VOCs lack of scientific research, mechanism analysis, just want to find what equipment to achieve, the results can be imagined. The success or failure of VOCs has risen to the problem of economic development and ecological environment coexistence, and will also be related to the security of China's industrial economy. do you really have nothing to do with VOCs? In fact, the domestic avant-garde environmental protection enterprises are working with domestic and foreign experts and scholars to apply the theory of organic chemistry research to sustainable green development, the results of which are the cross-penetration of organic chemistry and environmental protection science, in the organic exhaust gas treatment of the whole society concerned by "small molecules to inert chemical bonds of organic chemical reactions", "organic chemical atomic economy of high efficiency, high selectivity synthesis methods Asymmetric catalytic reaction theory, organic chemistry free radical chemical reaction processing algorithm, green organic chemical reaction and process chemical reaction processing system research, computational chemical reaction theory applied to VOCs processing equipment, realized the fundamental VOCs processing equipment to energy-saving, reliable, cheap, artificial intelligence height, for "Made in China 2025" submitted a qualified paving report. 。 VOCs processing research and development and application innovation must comply with "development is the first priority, talent is the first resource, innovation is the first driving force." "The pace of development of the times!"
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