Flow is down and to the left, before it turns up into cyclonic separator
We define scrubbers here as those venturi devices that are generally adopted for use at industrial plants to capture particulate dust. Water is used as the scrubber agent, although alkali can be employed, for those who wish to also remove certain gases in additional to particulate. The principle mechanism involves impact (impingement) of the dust particles and water droplets in order to achieve good contact.
For many industrial plants, many of them use some form of sodium compound to remove either reduced or oxidized forms of sulfur.
Although there are a number of venturi designs with an expanding and contracting throat that have been used through the years, many have found out the hard way that in most cases it is best to provide a fixed venturi throat. The convergent section generally contains a much more acute angle than the divergent section. Particulate removal can pose challenges of both the erosive and corrosive kind. Moving parts tend to gum-up over time.
Particulate removal efficiencies in the scrubber are increased by increasing the pressure drop through the venturi section of the particulate collector, either by decreasing the cross-sectional area of the venturi, or increasing the spray flow to the venturi throat. The cyclonic separator is designed to remove the venturi spray liquid.
Typical for very high pressure drops and very high liquid spray flux.
For a given design and configuration, most particulate greater than 1 micron is difficult and generally a poor choice for sub-micron particulate unless the flue gas pressure drop is very high, which can become quite expensive.