Based on the Organic exhaust gas (VOCS) characteristics and the current technical development, Huali has researched a high performance activated carbon adsorption, catalytic oxidation (CTO), thermal oxidation (RTO) and other organic waste gas treatment technology, according to the different conditions to choose the flexible combination.
Activated Carbon Adsorption Technology
Overview
The activated carbon adsorption technology can be used to process organic exhaust gases with a concentration between 0~1000 mg/m3 and blowing rate between 100~100,000 m3/h, exhaust gas working conditions with a high blowing rate and a low concentration or intermittent operation and situations with low or super-low concentrations such as essences or spices. It is widely used in various industries such as petrochemistry, leather, textile, printing and dyeing, paint, rubber, shoemaking, pharmacy, electronics, chemical fiber and brewing.
Processing Principle
Adsorption Process: the adsorption capacity of a solid surface is used. The exhaust gas contacts a porous solid substance with a big superficial area. Pollutants in the exhaust gas are absorbed at the solid surface to be separated from the gas mixture, thus realizing purification.
Desorption and Regeneration Process: after absorbing a certain amount of solvent, the activated carbon can be desorbed and regenerated. During regeneration, the steam is spayed from the bottom of the tower to steam out the solvent absorbed by the activated carbon; then it is condensed to liquid in the condenser, and enters the separator; organic solvents are separated and recycled; the residual enters the aerating pump, and is discharged after aeration.
Process Flow
After the exhaust gas is collected, dust is removed in the air filter and dehumidified in the dehumidifier; then it enters the adsorbent bed, and high-quality granular activated carbon or activated carbon fiber is used as the adsorbent to absorb pollutants on its surface through molecular attraction and capillary action, during which time oxygen and nitrogen are not absorbed. After being saturated from adsorption, desoprtion can be conducted through hot steam (lathe I and lathe II can be used alternatively); after concentration and desoprtion, the exhaust gas can be processed through condensate recycling, incineration, biodegradation and plasma processing. After desoprtion, the activated carbon/activated carbon fiber is desorbed through hot steam or vacuum for reuse.
Catalytic Oxidization Technology (CTO)
Overview
Because most organics are combustible, catalytic oxidization technology has become one of the most effective methods to purify exhaust gases with hydrocarbons.
Catalytic combustion methods is mainly applied to the treatment of organic exhaust gases under normal pressure, with large wind volume, with middle and low concentrations or with volatility. The organic solutions that this method can be used with include benzene, ketone, ester, aldehyde, ether, alkane and mixed solutions. It can be widely used in paint in the industries of automobiles, ship building, motorcycles, furniture, household appliances, pianos and steel structure manufacturers as well as purification of organic gases in painting workshops or production lines, and it can also be used with production lines of shoemaking viscose, can making, chemical plastics, cables and enameled wires.
Processing Principle
The Catalytic Oxidization (Catalytic Combustion) System adopts precious the metals of platinum and palladium as the catalyst, and at a temperature between 250~600 ℃, it catalyzes and combusts (or reduces) volatile organics or NOx in the tail gas and converts them into CO2, HCl, NO2, SO2, Cl2, H2O and N2.
Regenerative Technology of Oxidization (RTO)
Overview
Regenerative Technology of Oxidization mainly adopts the new ceramic heat-storage material, and by being combined with an advanced heat exchange design and technology, it reduces heat loss by a large amount. It can be used to treat organic exhaust gases with a concentration between 500～4000 mg/Nm3 of any substance, and the pollutant concentration which it can handle can be as high as 10000mg/Nm3; when the pollutant concentration reaches about 2000mg/Nm3, the equipment can maintain combustion by relying on its own hear at a rate higher than 5000Nm3/h. It is especially suitable to process organic exhaust gases with corrosive substances or substances toxic to the catalyst, as well as circumstances that require high-temperature oxidation or have stench.
Processing Principle
The regenerative oxidization equipment includes the following major parts: regenerative heat-storage towers, combustion chamber equipped with a combustor system and ventilation system equipped with a valve and fan. Its principle is to use the ceramic heat-storage body to store the heat generated by the decomposition of the organic gases, and then use the heat stored by the ceramic heat-storage body to decompose the organic gases that have not decomposed; in this way, VOC in the exhaust gas will be oxidized into CO2 and H2O in the oxidizing chamber, which will achieve great heat efficiency. The oxidization temperature is usually around 810~980 ℃, the chosen residence time is generally around 0.3～0.5S, and the oxidation conversion rates of ester, ether and aldehyde are all above 90%.
