What Is a Fume Scrubber?

Flue gas washing refers to the use of a certain washing liquid to wash the flue gas produced by industrial production. The process gas is in direct contact with the alkali solution or slurry, and at least a part of the pollutants of the process gas are captured in the alkali solution or slurry. ; And directly contacting the process gas depleted with the cooling liquid to form a cooled process gas; wherein the alkali solution or slurry is separated from the cooling liquid. Remove particulate matter, sulfur dioxide, nitrogen oxides and other harmful substances dissolved in the washing liquid in the flue gas, and reduce the flue gas temperature, so as to achieve the purpose of controlling flue gas pollutants and preventing environmental pollution. The commonly used flue gas scrubbers are mainly tower type, liquid column type, Venturi type, and dynamic wave type. ^[1]

Flue gas washing refers to the use of a certain washing liquid to wash the flue gas produced by industrial production. The process gas is in direct contact with the alkali solution or slurry, and at least a part of the pollutants of the process gas are captured in the alkali solution or slurry. ; And directly contacting the process gas depleted with the cooling liquid to form a cooled process gas; wherein the alkali solution or slurry is separated from the cooling liquid. Remove particulate matter, sulfur dioxide, nitrogen oxides and other harmful substances dissolved in the washing liquid in the flue gas, and reduce the flue gas temperature, so as to achieve the purpose of controlling flue gas pollutants and preventing environmental pollution. The commonly used flue gas scrubbers are mainly tower type, liquid column type, Venturi type, and dynamic wave type. ^[1]

Flue gas scrubbers are mainly of tower, liquid column, venturi and dynamic wave types.

Flue gas scrubber tower scrubber

Tower scrubbers are most widely used, mainly including spray towers, grid towers, swirl towers, bubble towers and other types. The pressure drop is generally 1.8 to 3. OkPa, and the desulfurization efficiency can reach 90% to 98%. The disadvantage is that the pressure drop is generally slightly larger. This type of washing and purifying method is that the flue gas goes in and out.

Flue gas washing liquid column scrubber

Liquid column scrubber. The washing liquid is sprayed upward from the nozzle in the tower to form a liquid column. During the vapor-liquid contact process in which the liquid column is scattered, the flue gas pollutants are removed, and the pressure drop is less than 2.0kPa. 90% to 95%. Simple liquid column scrubber. After the liquid column is sprayed upward, it spreads and falls at a high point, and comes into contact with the flue gas to remove the flue gas impurities. After removing the impurities, the flue gas is discharged into the chimney after passing through the high-efficiency demister.

Flue gas scrubber Venturi scrubber

In the Venturi scrubber, the gas passes through the Venturi throat at high speed, sucks the absorbent, forms fine droplets and liquid films, and mixes with the gas to remove pollutants such as S02 and dust in the flue gas. The pressure drop is generally greater than 2.0kPa, and the desulfurization efficiency can reach 60o / o to 80%.

Flue gas washing power wave scrubber

In terms of power wave scrubbers, the Dyna Wave technology was developed and patented by DuPont of the United States in the 1970s. The first industrial unit was put into operation in 2003. Tsinghua University, Nanchang Nonferrous Metallurgy Design and Research Institute, etc. have also applied for domestic patented scrubbers and washing technologies, mainly for the different optimization and unique design of the spray head of the power wave scrubber. The catalytic flue gas directly enters the power wave absorption tower from the top of the feed pipe, and a foam zone is continuously formed near the position where the vapor and liquid contact inside the feed pipe. The liquid surface in the foam zone is renewed at a very fast rate and the gas Quenching to adiabatic saturation temperature, it is used to pass gas through a strongly endured liquid film foam zone. By using the characteristics of large liquid surface area and rapid renewal in the foam zone, the gas-liquid mass and heat transfer process is strengthened, and S02 is absorbed. , S02 removal rate is above 99%. When the hot flue gas enters the feed pipe, it is immediately quenched by the lye from bottom to top, and the temperature is reduced to 50 to 60 ° C. At the same time, the catalyst dust in the flue gas is also washed out, and the flue gas can be quenched and acidic at the same time. Three functions: gas removal and solid dust removal. The purified flue gas is discharged into the chimney after passing through the foam trap. The collected liquid is returned to the power wave nozzle by the circulating pump. The nozzle with a large-aperture open design can produce the required foam area from the liquid sprayed by it, without atomizing the washing liquid, preventing a large amount of washing liquid from being taken away by the flue gas , Reduce the demister load, while the large-caliber nozzle can prevent nozzle clogging. In the process of washing with sodium alkali washing liquid, in order to completely oxidize the sulfurous acid pin and sodium hydrogen sulfite to a sulfuric acid pot to reach the COD value required by the discharged liquid, a compressed air is passed to the bottom of the washing tower and passed through a gas distributor. Full contact oxidation with the liquid phase, forced oxidation is carried out in the same column, the equipment is compactly arranged, and the footprint is small (see Figure 5-19). The pressure drop of flue gas after power wave washing is about 2 ~ 3kPa. This technology was industrialized abroad in 1985. It is mainly used in coal kilns, power plants, cement plants, industrial waste incineration, iron powder plants, coking plants, Boilers have been successfully applied to the flue gas treatment of 3 sets of catalytic cracking units. ^[1]