Washing treatment technology

Principle of Treating Chemical Washing Waste Gas

Chemical scrubber principle is mainly to use, according to the components of odour, strong acids (sulfuric acid), alkali (sodium hydroxide), strong oxidizing agents (sodium hypochlorite) as wash spray solution to implement gas-liquid contact with odor molecules in the gas, transfer the odor components in the gas phase to liquid phase, and remove the odor substance through neutralization, oxidation or other chemical reactions between chemicals and odor components. This is a good method to deal with the waste gas of chemical plant.

Chemical washing method can be applied to process odor substances including waste substances such as organic sulfur compounds, nitrogen-containing compounds, organic acid, compounds containing hydrogen, oxygen and carbon, halide-containing compounds, etc. It is suitable for sludge treatment, food, petroleum, chemical, pharmaceutical and other industries.

Washing equipment

Commonly used chemical washing equipment is packed column. Chemical absorption liquid sprays down from the top of the tower, the waste gas up flows, and the odor is eliminated after fully contacting and reacting with absorbing liquid. Ratio of absorption liquid to gas flow (liquid / gas ratio) is generally 1-3 L/m 3 , filling height is generally 2-5 meters, and air tower flow rate is generally 0.5-1 M / s. If the packed tower is well operated, the deodorant effect can reach more than 90%.

Chemical absorption type

Commonly used chemical absorbers include the following types:

(1) Alkaline solution

Alkaline absorption liquid usually uses solutions containing 1 ~ 10% sodium hydroxide which has a good effect on eliminating hydrogen sulfide. The effect of treating substances such as methyl mercaptan, methyl sulfide, dimethyl sulfide, lower fatty acid which often cause odor in waste water disposal site by such method is very excellent.

(2) Acid solution

Acid washing is mainly used to eliminate the odour caused by ammonia, tertiary amine and other alkaline gases, generally using sulfuric acid (0.5-5% solution) as washing liquid.

(3) Sodium hypochlorite solution

The alkalinity or acidity absorption liquid and sodium hypochlorite are commonly used together. It’s very difficult to eliminate methyl sulfide by other methods. Using sodium hypochlorite solution absorption, the control effect can be very good. When the concentration of odor in sewage treatment field is high, concentration of sodium hypochlorite solution (concentration of active chlorine) is about 500~2000 ppm; when dealing with odor of low concentration, use a sodium hypochlorite solution with concentration around 50~500 ppm. From the performance of oxidizing agent, sodium hypochlorite is most commonly used because it is the cheapest but with good effect.

In aqueous solution, sodium hypochlorite exists in the form of hypochlorous acid (HOCl) :

NaOCl+ H2O→HOCl+ NaOH......

When pH=7. 5, available chlorine hypochlorite solution exists in the form of 50% HOCI and hypochlorite ion (OCl - ). When pH = l0, only 0.3% of available chlorine exists in the form of HOCl; When pH = l1 or 12, HOCl is almost completely dissociated into useless hypochlorite ions, thus pH control is very important.

Waste gas treatment solution provider
Hotline:+86 513 85282870

Nantong KEAO Environmental Protection

Add: Gongnan South Road, Nantong City, Jiangsu Province

Tel: +86 513 85282870   Fax: +86 513 85353870





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