Analysis of purification process of dedusting equipment in workshop
(1) absorption device: the absorption device can be basically divided into three types, namely, packing tower, plate tower, spray tower (including venturi tube and jet pump). In addition, there are some special tower types, such as turbulent sphere tower, as shown in Figure 2-19. The packed tower is equipped with a certain height of packing layer. The liquid flows down the packing surface in a film shape from the top of the tower, while the gas is in a continuous phase and contacts with the liquid film in reverse flow from the bottom to the top. Mass transfer occurs in the plate tower. A certain number of plates are installed in the tower, when the gas passes through the liquid layer on the plate in the form of bubbling or spraying The spray tower is in direct contact with the gas and liquid in the tower.
(2) dedusting treatment: before absorption, it is the most ideal if a high-efficiency deduster (such as electrostatic precipitator) can be specially set up, but it may not be economical. It is more ideal if the flue gas can be removed together in the process of removing gaseous pollutants during absorption. For example, a pre washing tower is added in front of the absorption tower, or only one tower is used, the lower section is the pre washing section, and the upper section is the suction section The design requirements of the wet scrubber, which can not only remove dust but also absorb gas, should be paid more attention.
(3) pre cooling treatment: the absorption operation is expected to be carried out at a lower temperature, but some exhaust gases have a higher temperature, so it is necessary to cool the flue gas before absorption. The method can be heat exchanger, but the equipment is huge; it can also be used to humidify and cool the flue gas by direct injection of water, but it is easy to form acid mist to corrode the equipment or block the pipeline; at present, the pre washing tower or pre washing section is widely used, with better effect OK.
(4) heat treatment of purified gas: under the condition of cooling and humidifying a large number of flue gas and some unfavorable meteorological conditions, "white smoke" will occur, and white smoke will return to the ground before fully rising and diffusing, which will produce high concentration of pollution. One of the measures to prevent white smoke is to install tail skimming protection, tender burning of natural gas or heavy oil, so that a small amount of gas is mixed with purified gas, which has a better effect OK.
(5) waste liquid treatment: if the rich liquid absorbed gaseous pollutants is discarded, it will not only waste resources, but also cause secondary pollution. Therefore, it must be treated and utilized economically and reasonably. For example, if the alkali liquid absorbed SO1 in the waste gas can be regenerated by heating and reducing pressure to restore the capacity of the absorbent, and at the same time, the byproduct of sulfuric acid can be discharged; it can also be used to concentrate the rich liquid and The method of crystal separation and the by-product of sodium sulfite have achieved the goal of waste recycling.