Exhaust gas is mainly NaOH, H2SO4, SO2, H2S, HCl, NO2, HNO3 and other gases, according to the requirements of cleaner production, in the treatment process, first of all consider the purification of such substances as much as possible, required to achieve discharge standards.

Description of process flow:

The waste gas extracted by the fan, first entered wxs. Alkaline washing liquid absorption tower by the circulating pump to the tower by packing down flow, countercurrent acid mist emissions rise, in the wet surface of gas-liquid contact filler, a series of physical and chemical reactions, and the concentration difference and mass transfer process, thus completing the process of gas purification, the centrifugal fan out after standard exhaust gas purification after dehydration. The circulating liquid is discharged regularly to the sewage treatment station.

System composition of process flow:

The process is mainly composed of exhaust gas collection system, air intake system, exhaust gas purification system and exhaust system.

Exhaust gas collection and piping system:

Exhaust gas collection and piping system is mainly divided into exhaust gas collection system, exhaust gas delivery system and emergency exhaust and purification exhaust system.

For the waste gas treatment project, the exhaust gas is collected by Party A (manufacturer), and the exhaust gas collection of the project is directly connected with the draft fan outlet after the collection of the first party.

Explosion proof fan is adopted in exhaust gas transportation to overcome the resistance of the system. The press head of the fan is determined according to the structure of the cleaning system.

Process selection:

In view of the substance contained in the exhaust emission of the unit, the packing tower should be considered for the treatment plan. Spray tower is to use the principle of absorption to achieve the purpose of waste gas treatment.

Absorption treatment is the process of using liquid absorbent to treat gas mixture to remove one or several gases. In this process, the physical function of some gases dissolved in solution occurs, which is physical absorption. There is also a chemical reaction between the chemicals in the gas and liquid, which is chemical absorption.  Absorption is commonly used in the treatment and recovery of gaseous pollutants.

Absorption method is characterized by not only absorbing harmful gas, but also removing dust from exhaust gas. Absorption method can be divided into two kinds: physical absorption and chemical absorption. Physical absorption is a purely physical process of dissolving harmful gases and vapors with liquids. It is suitable for harmful gases and vapors with relatively large solubility in water, and the absorption efficiency is generally low. Chemical absorption is accompanied by an obvious chemical reaction in the absorption process, not a pure dissolution process. The chemical absorption efficiency is high, and it is the most harmful gas treatment method.

The method used in this process is the use of physical and chemical methods to treat exhaust gas, and the chemical absorption process uses NaOH solution as absorbent.

Hongfeng waste gas purification tower indicates that when alkali solution absorbs harmful gas, the concentration of lye has a great influence on the mass transfer rate of chemical absorption. When the alkali concentration is low, the chemical mass transfer speed is low; when the alkali concentration, mass transfer rate increases; when the concentration increased to a certain value, the mass transfer rate reaches a maximum value, then the concentration of the alkali liquid is called the critical concentration; when the alkali concentration is higher than the critical concentration of mass transfer rate does not increase.

Mist purification tower cleaning principle:

(1) -- the suction hood inlet pipe - fan (or inlet section) - inlet section of first filter layer (first level and secondary reaction zone) - filter layer (secondary neutralization section) swirl plate - hood cover - exhaust pipe (or a suction fan)

(2) mist purification tower working principle: mist purification tower using sodium hydroxide solution as absorption neutralizing liquid to purify exhaust gas mist. The gas is pressed into or sucked into the air inlet section by the centrifugal fan, and then flows upwards to the first filter material layer and contacts with the neutralization liquid ejected from the first spray nozzle. After absorption of the exhaust gas continues to flow upward to the second filter layer, and the liquid contact with the second stage nozzle, again reacted by swirl plate, and the exhaust pipe by the hood or fan into the atmosphere.

Mist purification tower features:

Polypropylene acid mist purification tower with high efficiency, strong corrosion resistance, high strength, low noise, low power consumption, small volume, easy disassembly and maintenance, high durability, beautiful appearance and other advantages.

Hongeng waste gas purification tower was informed that the current domestic treatment of corrosive gases (such as acid, alkaline waste gas), the most widely used is liquid absorption treatment. The waste gas absorption by liquid treatment, is the key choice of mist purification tower.

Mist purification tower has high purification efficiency, simple operation and management, the use of acid and alkaline waste gas purification technology and equipment of long life. It has the advantages of simple structure, low energy consumption and high purifying efficiency and wide application range, can effectively remove the hydrogen chloride gas (HCl), acid gas (HNO3), hydrogen fluoride (HF), ammonia (NH3), sulfuric acid mist (H2SO4), chromic acid (CrO3), hydrogen cyanide (HCN), gas alkali vapor (NaOH), hydrogen sulfide (H2S), water soluble gas. Sodium hydroxide was used as absorption neutralization solution, and the solution concentration was 8%-16%.

The introduction of acid mist exhaust purification tower by air duct, exhaust gas passes through the filler layer, and sodium hydroxide absorption liquid two-phase full contact absorption neutralization reaction, acid mist purification tower exhaust gas after purification, followed by dehydration defogging plate fog by the fan into the atmosphere. The absorption liquid is sprayed at the bottom of the tower after the booster of the water pump, and finally returns to the bottom of the tower to be recycled.