Wet Scrubbers is used as a pretreatment device in waste gas treatment, which plays the function of dust removal and cooling, and plays a key role in many waste gas treatment. At present, there are two types of spray towers on the market: horizontal and vertical.
Vertical Flow:
Gas flow is counter-current to the liquid flow.
Smaller footprint required at the expense of increased height requirements.
Generally, less costly from both capital and operational perspectives.
Scrubber vessel is round (generally).
Crossflow/Horizontal Flow:
Gas flow is cross-current (perpendicular) to the liquid flow.
Sacrifices footprint for height.
Slightly less efficient due to cross-current flow, although this disadvantage is minimized when treating the more water-soluble acids (e.g. H2SO4, HCl).
Scrubber vessel is rectangular
Wet Scrubbers is a two-phase counter-flow packed absorption tower, which is a two-phase counter-flow packed absorption tower. When the acid gas enters the Wet Scrubbers tangentially from the air inlet under the tower body, under the power of the fan, it quickly fills the space of the air inlet section, and then evenly rises to the packing layer through the equalizing section.
On the surface of the filler, the acidic substances in the gas phase react with the alkaline substances in the liquid phase, and the reacted substances (mostly soluble acids) flow into the lower liquid storage tank with the absorbing liquid. The acid gas that is not completely absorbed continues to be produced and enters the secondary spray section. In the spray section, the absorbing liquid is sprayed out from the uniformly distributed nozzles at high speed, forming numerous fine droplets, which are fully mixed and contacted with the gas, and continue to undergo chemical reactions. Similar absorption process.
The nozzle density of the second stage and the first stage are different, the injection pressure is different, and the concentration range of the absorbed acid gas is also different. The process of two-phase contact in the spray section and the packing section is also a process of heat transfer and mass transfer. By controlling the superficial flow rate and residence time, the process is fully and stable. The upper part of the tower is the defogging section, where the absorbed liquid droplets trapped in the gas are removed, and the treated clean air is discharged into the atmosphere from the exhaust pipe at the upper end of the Scrubber.
The production and manufacture of wet scrubbers need to consider the application environment, and the exhaust gas emitted by many factories is corrosive. Therefore, anti-corrosion materials are generally used to make wet scrubbers, such as stainless steel, polypropylene PP, and glass fiber reinforced plastic. If the exhaust gas temperature is higher than 100°C, stainless steel is recommended. PP polypropylene scrubbers are cheap and suitable for small production enterprises.
