What are the common waste gas treatment methods?
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Commonly used exhaust gas treatment:
1, absorption purification method
Absorption is the purification of gaseous pollutants z commonly used methods. Absorption method is defined as: the use of appropriate liquid absorbent for exhaust gas treatment, so that the exhaust gas in the gaseous pollutants dissolved into the absorbing liquid or with the absorption of a certain active component of the liquid chemical reaction into the liquid phase, so that the gaseous pollutants from the exhaust gas separated from the method; or, the use of absorbent will be one or more components of a mixture of gases to selectively absorb the separation of the process known as the absorption.
Absorption is often divided into physical absorption and chemical absorption, the difference is shown in the following table:
2, adsorption purification method
Adsorption is the use of porous solid adsorbent treatment of fluid mixtures, so that one or more components contained therein are adsorbed on the surface of the solid, in order to achieve the purpose of separation. The difference between the adsorption process and absorption is that: after absorption, the absorbing components are uniformly distributed in the absorbing phase, and after adsorption, the adsorbed components are aggregated or concentrated on the adsorbent, only y a non-homogeneous phase process.
At present, the adsorption operation in the organic chemical industry, petrochemical and other production sectors have been more widely used. The use of this method in environmental engineering is also very common, the main reason is the high selectivity of the adsorbent, it can separate the other process is difficult to separate the mixture, the effective removal of very low concentration of hazardous substances, equipment is simple, easy to operate, high purification efficiency, and can be realized automatically controlled.
The adsorption process is a dynamic process in which the adsorbent is adsorbed on the surface of the adsorbent by diffusion of adsorbent from the fluid to the surface of the adsorbent and the inner surface of the micropores, releasing heat. The desorption process is a process opposite to the adsorption process.
After the adsorbent adsorbs on the surface of the adsorbent, the internal energy of the molecules of the adsorbent is lowered due to changes in the form of molecular motion, such as diffusion, vibration, and rotation, thus releasing energy, which is called the heat of adsorption. Heat of vaporization and heat of binding are the two components of heat of adsorption. The heat of adsorption is about 1.5 times greater than the heat of vaporization of a substance, not excluding special cases. In general, the heat of adsorption is affected by the amount of adsorption, the temperature of adsorption, and the velocity of the fluid air tower at the time of adsorption, etc., and if the heat of adsorption is not induced in a timely manner, a part of the heat absorbed by the desorbed molecules will have a negative effect on the adsorption process.
3, condensation purification method
Condensation purification method is the use of substances at different temperatures have different saturated vapor pressure of this property, the use of cooling, pressurization methods to make the gas in the vapor state condensation and separation of exhaust gas, in order to achieve the purpose of purification or recovery.
The degree of removal of harmful gases by condensation purification is related to the cooling temperature and the saturation vapor pressure of the harmful components, the lower the cooling temperature, the harmful components are close to saturation, the higher the degree of removal. It is particularly suitable for the treatment of exhaust gas concentration of 10,000 * 10-6 or more organic solvent vapors, is not suitable for the treatment of low concentration of exhaust gas. The condensation process can be realized by raising the pressure at a constant temperature or by lowering the temperature at a constant pressure. Exhaust gas can be purified by condensation, but the cooling water at room temperature cannot reach the high purification requirements, in order to purify the complete q, need to lower the temperature and pressure, which makes the treatment more difficult and increases the cost. Therefore, usually adsorption, combustion and other means and condensation of the joint use of hair as a net high concentration of organic gases pre-treatment, in order to achieve the realization of organic load reduction, recovery of valuable products. In addition, condensation purification is generally only applicable to the air contains a high concentration of steam, so the concentration of steam into the condensing device can be above the explosive limit, and condensing device out of the concentration can be below the lower explosive limit, in condensation is exactly between the upper and lower explosive limit, which is not conducive to a full a disadvantage.
4, catalytic purification method
Catalytic purification method is to make the gaseous pollutants through the catalyst bed, under the action of the catalyst, undergoing catalytic reaction, into harmless substances or easy to handle and recycling of substances purification method. Catalytic purification method has catalytic oxidation method and catalytic reduction method. Catalytic oxidation method: the pollutants in the exhaust gas are oxidized under the action of catalyst. Such as SO2 in the exhaust gas in the catalytic organic compounds of the exhaust can be decomposed into H2O and CO2 through the oxidation process of combustion to the outside. Catalytic reduction method, is to make the pollutants in the exhaust gas under the action of the catalyst, and reducing gas reaction purification process. Such as NOx in the exhaust gas under the action of the catalyst and NH3 reaction to generate harmless gas N2. catalytic purification is characterized by the avoidance of secondary pollution that may arise from other methods, but also to simplify the operation process, for different concentrations of pollutants have a high conversion rate. Its main application lies in the conversion of hydrocarbons into carbon dioxide and water, nitrogen oxides into nitrogen, sulfur dioxide into sulfur trioxide and recycling, catalytic combustion of organic waste gases and odors, as well as catalytic purification of automobile exhaust. The disadvantage is that the catalyst price is higher, exhaust gas preheating to consume a certain amount of energy.
The content of pollutants in the exhaust gas is usually low, with catalytic purification method of treatment, there are often the following characteristics: 1) due to the low content of pollutants in the exhaust gas, the process of thermal effect is small, the reactor structure is simple, and more fixed-bed catalytic reactor. 2) to deal with the amount of exhaust gas is often very large, the catalyst is required to withstand the impact of the fluid flushing and pressure drop. 3) due to the purification of the requirements of the high, and the exhaust gas is a complicated composition, some of the reaction conditions change greatly, and the reaction conditions change. 3)Because of the high purification requirements and the complex composition of the exhaust gas, the catalyst is required to have high selectivity and thermal stability due to the large changes in the reaction conditions.
5, biological method
In Genf-Villetted once with biological purification device to purify exhaust gas. Biological method of waste gas treatment technology in the 20th century 80 ~ 90 years has been the rapid development of the Netherlands and Germany became s batch of large-scale application of biotechnology to treat waste gas g home. Subsequently, the application of biotechnology in waste gas treatment is also more and more extensive, the current use of biological purification gas device in Europe has c over 7500, half of which are used to treat sewage as well as compost odor, about the purification principles of biochemical gases and engineering application experience of a set of important system has also been formed. Biological purification technology to make up for the shortcomings of the traditional physical and chemical treatment technology, the traditional method requires special anq operation procedure management, and high energy consumption, high economic investment, in contrast, biological purification method belongs to the clean type of treatment method, become the exhaust gas treatment, especially biochemical exhaust gas treatment of the frontier and hot spot.
Biological exhaust gas purification technology is a multidisciplinary cross environmental protection high-tech. Specifically, it is a low concentration of industrial waste gas purification of cutting-edge hot spot technology, which has been established in the mature use of microorganisms to deal with wastewater methods. Domestic research has shown that the low concentration of industrial waste gas has been unable to conventional technology for economic and effective purification and treatment, but the use of biological waste gas purification technology to deal with low concentration of industrial waste gas is effective, with obvious technical and economic advantages.
6, membrane separation purification
Membrane purification method is a mixture of gases under the action of the pressure gradient, through a specific film, different gases have a different speed of transmission, so that different components of the gas mixture to achieve the effect of separation. Pressure difference, concentration difference and potential difference drive the membrane separation process. Membrane separation technology is a new type of separation technology that utilizes membranes to separate, purify and concentrate mixtures according to the differences in selective permeability properties of the components in the mixture. Can be a specific form of restriction and transfer of fluid substances separated two phases or two parts of less than two interfaces, these two interfaces are the two sides of the fluid contact as well as the transfer of the bridge. For the fluid, the separation membrane can be semi-transparent can also be complete q through, but never w all impermeable.
The main feature of membrane separation is to realize the separation of mixtures and molecular sizes of substances, which will selectively permeable membrane as a means of separation. Phase changes do not occur in the membrane separation process, so the operation can be carried out at room temperature, which avoids the concentration and enrichment of the nature of the substance due to high temperature and change the disadvantage, in the food, pharmaceutical and other industries membrane separation so the advantages of the membrane is widely used. Less energy consumption, low cost, high efficiency, no pollution and can recover useful substances is the membrane separation **** have advantages, for isomeric components, similar nature components, heat-sensitive components, biological components and other components of the separation of mixtures, membrane separation method is very suitable, sometimes instead of distillation, extraction, evaporation, adsorption and other chemical unit operations. Practice shows that if conventional separation can not be realized by economic methods, membrane separation will become a very useful technology. Combining conventional separation with membrane separation is a more cost-effective technology. Combining the above advantages, membrane science and membrane technology in the last two or three decades has been rapid development, has become industrial and agricultural production, national defense, science and technology and people's daily life in the separation method, more and more widely used in the chemical industry, environmental protection, food, medicine, electronics, electric power, metallurgy, textiles, desalination and other ling domain.
7, combustion purification method
The combustion method to destroy toxic gases, vapors or soot, so that it becomes non-toxic, harmless substances, called combustion purification. Combustion purification can only destroy which combustible or decomposition of toxic gases and soot at high temperatures, the chemical action is mainly combustion and oxidation, and in individual cases is thermal decomposition. Combustion purification, can be widely used in organic solvent vapors and hydrocarbon purification treatment, these toxic substances in the process of combustion oxidation of higher concentrations, heat generation of flammable harmful gases, combustion temperature is generally in the 600 ~ 800. C. The combustion method is simple and easy to implement, can be recycled heat, but can not be recycled hazardous gases, easy to cause secondary pollution.
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What is a good way to deal with factory exhaust gas
√Hello owner, according to your question, the following for you to do a detailed answer:
Industrial exhaust gas purification and treatment of factory emissions, roughly divided into three important links, the steps are from the collection of exhaust gas, to exhaust gas treatment equipment and processes to purify, and then to the end of the gas detection standards and then discharged into the atmosphere by the chimney. Below we will bring you a detailed understanding, if you have factory exhaust treatment needs, contact us immediately! Look forward to working with you.
What must the factory exhaust be treated?
One, exhaust gas collection
In the factory exhaust emissions of various pollution source points, according to the actual production conditions, choose the appropriate side or top suction exhaust suction hood, one by one with the air duct connection to form a complete exhaust collection system, Zui after the power of the induced draft fan on the collection of exhaust gas.
Because of the different waste gas treatment processes, before the collection of waste gas, consider the complexity of the composition of the waste gas discharged from the factory, for different properties of the waste gas is categorized and collected, so as to facilitate the purification of the end of the waste gas to meet the standards.
Second, the choice of exhaust gas treatment equipment and purification process
After a clear understanding of the composition of the exhaust gas emissions from the factory, the concentration and exhaust volume values, the first to determine the exhaust gas treatment process, and then from the manufacturer to purchase exhaust gas treatment equipment.
The installation site is selected according to the size of the exhaust gas treatment system in a vacant place in the factory, and then the ground is leveled and cement hardened, so that the equipment can be installed when it comes into the factory.
Or consult an environmental protection company, explain the parameters of the factory's exhaust gas emissions, and provide them with exhaust gas treatment solutions, and then purchase the corresponding exhaust gas treatment equipment from the manufacturer according to the requirements of the exhaust gas process design.
Contact the environmental engineering company, if the company's qualification meets the requirements, by the designated exhaust gas treatment site to install exhaust gas treatment equipment, until the equipment is installed, debugging and operation.
Three, exhaust gas emission testing
Zui is the exhaust gas testing link, which will relate to or affect the factory emissions after purification of exhaust gas, chimney vent gas test whether it is up to standard, whether it is in line with the national J or the local environmental protection department's emission requirements. Exhaust gas emission detection is divided into offline detection and online monitoring of two kinds, most of the small and medium-sized enterprises are offline monitoring, online monitoring of the installation requirements by the State J environmental protection departments in accordance with the nature of different industries, scale and exhaust characteristics to determine the installation or not.
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What are the general methods of exhaust gas treatment
Organic exhaust gas treatment methods are as follows:
One is the masking dilution method. As the name suggests masking dilution is through the use of other odors of the gas, masking the exhaust gas in the annoying and uncomfortable odor, to achieve the purpose of deodorization; and dilution of the law is through the drum into the air on the concentration of high odors to dilute, until through the human body senses is difficult to perceive as a result. This method is essentially from the sensory level to eliminate the negative impact of odor, but the odor caused by the odor factor still exists.
The second is the absorption method. This is also the current municipal and industrial deodorization of the highest popularity, one of the most widely used technology, mainly using activated carbon and other adsorbents, its porous structure has a large surface area and van der Waals force, the exhaust gas molecules, including malodor factor adsorption, to achieve the effect of separation of the airflow. Although the technology has matured and the cost is relatively low, but the odor-causing components are not really removed, the subsequent adsorbent still need to be desorbed and secondary treatment and other operations, and the service life is shorter, to cope with the high concentration of odorous gases when the effect is not good.
Third is the cracking method. Through a variety of means on the malodorous gas molecules decomposition and destruction, directly from the source of odor to solve the problem of waste gas treatment, with the development of environmental protection industry technology, the industry has been born such as combustion, high temperature cracking method, chemical method, UV photolysis, plasma method and biological method, etc.. The super-energy plasma method and biological method as the deodorization industry's emerging application of technology, due to high deodorization efficiency, low energy consumption, high safety factor, does not produce secondary pollution and other advantages are being more and more widely used.
KeWei environmental protection research and development of ion tube using German bioclimatic original imported high-tech core components, ion tube material structure to join the titanium, neodymium, cerium and other rare elements. The main structure of the generator by the quartz ion tube and mesh electrodes composed of positive and negative, ion tube wrapped in the quartz cavity on the inside, not in contact with the external mesh electrodes, compared to the market process is not mature general ion tube competitors, as low as 0.1mm level of extremely fine ring space in the formation of the distribution of electric field lines, to ensure that the air and the pollution of gas molecules to ensure that the full contact.
The ion tube is encapsulated and reinforced with a high-density PVC sealing ring, the bottom of which is connected to the ion base through a screw port for easy loading and unloading; the mesh electrodes are connected to the steel columns on the ion base through metal toggle contacts for circuitry access, which is more suitable for later maintenance and overhaul. The control device includes ion concentration adjustment and power supply, etc., the internal wire alignment is clear and regular, easy to maintain, reflecting the quality of German precision work everywhere. The mesh electrode is made of 304 stainless steel, and the line is protected by wear-resistant, high-temperature and corrosion-resistant insulating rubber winding, and the base is upgraded with anti-corrosion and anti-rust technology.
Super ion tube supporting the use of special transformers with thin structure, strong stability, durability and other characteristics. Built-in customized chip on the voltage and current within the device to implement dynamic control, compared to the UV ultraviolet throttle and plasma competitors use the general transformer is susceptible to high temperature or voltage instability and paralysis of the impact of the equipment supporting the special transformer greatly extends the service life of the product, saving maintenance costs. Although the ordinary transformer compared to the special transformer price is cheaper, such as the market passes ordinary transformer offer is generally 200 ~ 600 yuan, and the well-known special power supply supplier Abach only transformer offer has been more than 2,000 yuan, but our company used the German bioclimatic super plasma tube supporting the special transformer in the "quality standards Abach, price Strive for more affordable" under the premise that the cost has been included in the plasma tube set, to achieve a one-time investment, lifelong benefit.
The effective method of exhaust gas treatment is introduced?
√Hello owner, according to your question, the following for you to do a detailed answer:
Biodegradation method
The use of circulating water flow, so that the pollutants in the gas in the water, and then the use of aquatic culture beds, the culture of micro-organisms, the pollutants will be degraded, this industrial waste gas treatment method can be effective deodorization.
Activated carbon adsorption method
Using the principle of activated carbon structure, adsorption of malodorous gas molecules, the initial processing efficiency is relatively high, but this industrial waste gas treatment method also has certain limitations, because the activated carbon is very easy to be saturated, a few days that is, it is ineffective, and need to be replaced frequently, so the maintenance cost is high.
Plasma method
Environmental protection equipment manufacturers use high-pressure electrodes, emitting ions and electrons, destroying the molecular structure of malodors, cracking malodor molecules. This method is mainly applicable to low concentration of malodorous gas purification, the treatment effect is obvious.
Activated carbon adsorption
It is a high-efficiency, economical and practical organic waste gas purification and treatment device; it is a waste gas filtration and adsorption of odors of environmental protection equipment products. Activated carbon adsorption tower is characterized by high adsorption efficiency, wide applicability, convenient maintenance, and the ability to deal with a variety of mixed exhaust gas at the same time.
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