Views: 4 Author: Xicheng EP LTD Publish Time: 2022-06-20 Origin: Xicheng EP LTD
With the advent of the information age, the semiconductor industry is also developing rapidly. The economic benefits and employment rate brought by semiconductor factories to the society are obvious to all, but there is also pollution to the atmosphere. Since the semiconductor industry has extremely high requirements on the cleanliness of the operating room, fans are usually used to extract various types of waste gas volatilized during the process. Therefore, the waste gas emission of the semiconductor industry has the characteristics of large exhaust volume and low emission concentration.
Main components: The waste gas in the semiconductor industry is mainly divided into two types: organic waste gas and acid-base waste gas. Organics include: non-methane total hydrocarbons, nitrogen oxides, sulfur dioxide, etc.; acids and bases include ammonia, sulfuric acid mist, fluoride, chloride, chlorine, etc.
Main source: Harmful gases that cause environmental pollution in the semiconductor industry mainly come from the cleaning, homogenizing, degumming, etching, and developing processes of chip or circuit board production.
Main hazards: The semiconductor industry is mainly caused by the use of some chemical agents (such as sulfuric acid, hydrochloric acid, CFC, carbon tetrachloride, trichloromethane, etc.) The volatilization of ethyl chloride and other organic halides will cause pollution to the atmospheric environment, as well as mechanical noise and a small amount of dust generated during the assembly process of the whole machine, which will also cause environmental pollution. These polluted gases will cause chronic or acute poisoning of the population.
Acid and alkaline waste gas
Process flow: acid/alkaline waste gas→acid/alkaline scrubber→centrifugal fan→chimney (standard discharge)
The acid and alkali waste gas is collected by the collection pipeline and then enters the corresponding chemical washing tower for spray treatment according to their respective systems. The chemical washing tower independently developed and designed by Greenstar passes the internal spray system, circulating water system, packing filter system, removal Fogging system, automatic dosing system, automatic water supply and drainage and other systems perform chemical absorption and defogging of the exhaust gas entering the chemical scrubber, so as to ensure that the exhaust gas after treatment meets the discharge standards.
The chemical scrubber can effectively remove the acid/alkaline gas contained in the waste gas, and the waste gas treatment equipment is produced with FRP as the main material. The packing is made of PP Mehler ring. According to the principle that the gas-liquid two-phase conducts mass transfer reaction on the surface during the gas absorption process and the transfer rate is proportional to the specific surface area, the filler is used to increase the specific surface area of the two-phase contact, so that the two phases are fully contacted, so as to achieve absorption and The purpose of purifying exhaust gas. The moisture content of the purified gas is relatively large, so that the gas passes through the defogging layer, and the defogging layer packing can effectively absorb the moisture in the gas, and the purified gas is discharged from the air outlet.
The working principle of the washing tower: the structural type of the washing tower is divided into vertical and horizontal.
The working principle of the vertical scrubbing tower is gas-liquid two-phase countercurrent contact; the waste gas containing acid and alkali pollutants enters the tower from the lower inlet of the tower and moves upward, and through single-layer or multi-layer packing, the waste (tail) gas is fully contacted with the liquid phase. After absorption or neutralization, the clean gas is discharged through the upper demister layer, so as to achieve the effect of absorption and purification.
The working principle of the horizontal structure is gas-liquid two-phase cross-flow contact. When the waste (tail) gas passes through the packing layer, it is fully contacted with the liquid phase and then absorbed or neutralized, so as to achieve the effect of absorption or purification.
The equipment itself includes a washing tower body, a packing layer, a demisting layer, a circulating water pipeline, and a circulating water tank.