Views: 7 Author: XICHENG EP LTD Publish Time: 2021-08-23 Origin: XICHENG EP LTD
1. Washing method
Principle: The gas is sent to the scrubber with spray system. The gas passes through the evenly distributed packed bed and fully contacts the scrubbing liquid. Using the solubility or chemical properties of pollutants in the gas, the pollutants in the gas are adsorbed or removed through chemical reactions, so as to achieve the purpose of purifying the gas. In addition, the scrubber also has the functions of cooling, dust removal and oil removal. The usual method for industrial waste gas treatment equipment, waste gas treatment equipment, and organic waste gas treatment equipment is countercurrent washing. Commonly used detergents are water, plant liquid, sulfuric acid solution, sodium hydroxide solution, sodium hypochlorite solution and so on. Among them, clean water washing and plant liquid washing take advantage of the solubility of pollutants, and part of the plant liquid also participates in chemical reactions. Sulfuric acid solution washing, sodium hydroxide solution washing and sodium hypochlorite washing take advantage of the chemical properties of pollutants.
The reaction is rapid, and the contact time between the detergent and the gas is generally no more than 12 seconds;
Strong applicability, often combined with other treatment processes, is an effective pretreatment facility;
Use ordinary vertical structure to save construction area;
The operation is simple, except for the regular replacement of the cleaning agent, basically unmanned operation (the replacement of the cleaning agent can also be realized by adding a PLC automatic control system);
The process is flexible. If the nature of the gas changes, the detergent can be used again;
The construction cost is low.
It has the functions of dust removal, oil removal, cooling, deodorization, etc., with strong applicability. It is often used as a pretreatment equipment for other processes.
Used in the petrochemical industry
The specific manifestation of the washing method applied in the petrochemical industry is the oil washing tower. The oil washing tower is the key equipment in the heat recovery area of the ethylene plant. Industrial waste gas treatment equipment, waste gas treatment equipment, and organic waste gas treatment equipment whose function is to condense heavy oil and light oil components from the cracked gas of the cracking furnace to achieve maximum heat recovery. The principle is that the cracked gas of the cracking furnace is in countercurrent contact and cooling with the fast cooling oil/water, so that the heavy oil and light oil components in the cracked gas are condensed. The condensing heat medium and the refrigerant can exchange heat through direct or indirect contact.
2. Catalytic combustion method
Principle: The exhaust gas enters the heat exchanger of the purification device through the induced draft fan for heat exchange, and then enters the heating chamber. Through the heating device, the gas reaches the catalytic reaction temperature. Then, through the action of the catalyst on the catalytic bed, the organic gas is decomposed into carbon dioxide and heat energy.
When the concentration is high, the energy consumption is only the power of the fan, and when the concentration is low, the heating is automatically intermittently compensated;
Catalytic ignition temperature is 300~500℃.
Medium and high concentration organic waste gas, the best concentration is 2500-3000mg/m3;
Mainly for hydrocarbons, benzene, ketones, ethers, esters, alcohols, and phenols.
Used in the petrochemical industry
Catalytic combustion technology is suitable for the treatment of high-concentration organic waste gas, and it has matured itself. However, the one-time investment and maintenance cost of this method is relatively high, and its application to the treatment of large-scale exhaust gas will bring a greater economic burden to the enterprise. In addition, if the temperature of the catalyst bed is not well controlled, there is a danger of explosion. Therefore, explosion-proof safety measures should be taken when using this technology.
3. Direct combustion method
Principle: Use the combustion heat of the auxiliary fuel to raise the temperature of the combustible harmful gas to the reaction temperature, thereby causing oxidation and decomposition.
The thermal combustion method is used to oxidize and decompose the pollutants in the exhaust gas, provide sufficient combustion oxygen and a certain residence time at a suitable temperature, with high deodorization efficiency and high purification rate. At the same time, the device host works stably without blocking.
Medium and high concentration organic waste gas. Such as solvent discharge: benzene, ketone, etc.
Used in the petrochemical industry
The direct combustion method has higher requirements for exhaust gas, and it is necessary to analyze specific problems.
4. Regenerative catalytic purification (RCO)
Principle: The combination of low-temperature catalytic oxidation and heat storage technology is a kind of organic waste gas purification technology.
Adopting preheating and heat storage alternate switching technology, the heat exchange efficiency is high, the efficiency can reach more than 90%, and the energy saving performance is remarkable;
It has the same characteristics as the catalytic combustion method.
It is suitable for organic waste gas treatment in coating lines, drying rooms, chemical industry, chemical synthesis process (ABS synthesis), petroleum refining and other organic waste gas generating places. When the gas contains S, halogen, etc., the catalyst can be inactivated.
5. Regenerative thermal oxidation (RTO)
Top left: loaded precious metal catalyst; bottom left: top view of ceramic heat accumulator; top right: honeycomb activated carbon; bottom right: honeycomb ceramic valve body.
Principle: Organic waste gas treatment technology combining high temperature oxidation and heat storage technology.
Preheat the combustion chamber and the regenerator bed before exhaust gas treatment. After preheating, connect the exhaust source to the equipment. Under the action of the supporting fan, the organic waste gas is first exchanged through the preheated heat storage ceramic body 1. After heating once, the exhaust gas enters the heating zone. Industrial waste gas treatment equipment, waste gas treatment equipment, and organic waste gas treatment equipment heating zone waste gas is reheated. The treated clean gas is discharged through the heat storage ceramic body 2 by a fan. When the temperature is detected by the temperature measuring rod of the intake and exhaust fan and reaches the set temperature, the valve is from the exhaust gas of the ceramic heat storage body 2 and the heat storage ceramic body 1, and the cycle repeats.
Adopt preheating and heat storage alternate switching technology, high heat exchange efficiency, the efficiency can reach more than 90%, and the energy saving performance is remarkable;
The internal combustion engine is used for heating, which can realize the proportional adjustment function of high and low power operation, and has the functions of pre-cleaning, fire prevention, over-temperature alarm, and automatic cut-off of fuel supply; operation is safe, reliable, efficient, and durable;
Using microcomputer automatic control and multi-point temperature control to realize various protection actions, operation information retrieval and monitoring information feedback, so that the system can operate safely, stably and reliably;
The valve adopts pneumatic transmission mechanism. Compared with electric transmission mechanism, the valve switch is more sensitive and faster;
Suitable for medium and high concentration organic waste gas
It is suitable for coating line, printing, chemical synthesis process (ABS synthesis), petroleum refining and chemical process in various places where organic waste gas is produced.