Waste gas scrubbing tower

Waste gas scrubbing tower

Introduction to Waste Gas Scrubber Tower

A washing tower is a device for coarse separation, consisting of four parts: tower body, tray, reboiler, and condenser. The number of trays is usually small, generally not exceeding ten. Waste gas containing a small amount of dust is more suitable for separation using a washing tower. In the washing tower, the components of the waste gas do not react and the products are easily liquefied.

When the mixed exhaust gas is introduced into the washing tower, due to the presence of product component liquid between the trays, a portion of the product component gas liquefies and evaporates. Impurities cannot be liquefied or solidified, and will be fixed by the product component liquid when passing through the trays with liquid, producing a washing effect. The washing tower is designed and manufactured based on this principle.

(Waste gas scrubbing tower)

【2、 Working principle of exhaust gas scrubbing tower】

The principle of a washing tower is mainly based on the composition of the odor, using strong acids (sulfuric acid), strong bases (sodium hydroxide), and strong oxidants (sodium hypochlorite) as washing spray solutions to come into contact with odor molecules in the gas, transferring the odor components from the gas phase to the liquid phase, and using chemical agents to neutralize and oxidize the odor components to remove the odor substances.

The commonly used washing equipment is a packed tower, where the chemical absorption liquid is sprayed downwards from the top of the tower, and the exhaust gas flows upwards. The odor is fully contacted and reacted with the absorption liquid to be removed. The ratio of absorption liquid to exhaust gas flow rate (liquid/gas ratio) is generally 1-3 L/m3, the packing height is generally 2-5 meters, and the gas flow rate in the empty tower is generally 0.5-1 meters/second. A well operated filling tower can achieve a deodorization effect of over 90%.

Common chemical absorbents include the following:

(1) Alkaline solution

Alkaline absorbent solutions commonly contain 1% to 10% sodium hydroxide solution, which is effective in eliminating hydrogen sulfide waste gas and other substances that often cause odors in wastewater treatment plants, such as methyl mercaptan, methyl sulfide, methyl disulfide, and lower fatty acids.

(2) Acidic solution

(3) Sodium hypochlorite solution

Sodium hypochlorite is generally used together with acidic and alkaline absorbent solutions. For sulfurized methyl groups that are difficult to eliminate by other methods, the use of sodium hypochlorite absorption solution has a very good control effect. When dealing with high concentration odors, the concentration of sodium hypochlorite solution (effective chlorine concentration) is about 500-2000 ppm; When dealing with low concentration odors, sodium hypochlorite solution with a concentration of about 50-500 ppm is used. In terms of the performance of various oxidants, sodium hypochlorite is cheap and has good treatment effects, so it is widely used.

(Working principle of exhaust gas scrubbing tower)

【3、 Performance characteristics and applicability range of exhaust gas scrubbing tower】

(Waste gas scrubbing tower)