Venturi scrubber
A venturi scrubber accelerates the gas stream to atomize the scrubbing liquid and to improve gas-liquid contact. In a venturi scrubber, a "throat" section is built into the duct that forces the gas stream to accelerate as the duct narrows and then expands. As the gas enters the venturi throat, both gas velocity and turbulence increase. The scrubbing liquid is sprayed into the gas stream before the gas encounters the venturi throat. The scrubbing liquid is then atomized into small droplets by the turbulence in the throat and droplet-particle interaction is increased. After the throat section in a venturi scrubber, the wetted PM and excess liquid droplets are separated from the gas stream by cyclonic motion and/or a mist eliminator. Venturi scrubbers have the advantage of being simple in design, easy to install, and with low-maintenance requirements. The performance of a venturi scrubber is dependent to some extent on the velocity of the gas through the throat. Because of the high interaction between the PM and droplets, venturi scrubbers are capable of high collection efficiencies for small PM. Unfortunately, increasing the venturi scrubber efficiency requires increasing the pressure drop which, in turn, increases the energy consumption.