page_title: Venturi scrubber
section_title: Maintenance considerations
hierarchical_section_title: Venturi scrubber / Maintenance considerations
context_page_description: A venturi scrubber is designed to effectively use the energy from a high velocity inlet gas stream to atomize the liquid being used to scrub the gas stream. This type of technology is a part of the group of air pollution controls collectively referred to as wet scrubbers.
  Venturis can be used to collect both particulate and gaseous pollutants, but although the liquid surface area provided is quite large they are more effective in removing particles since particles can be trapped by contact, but gasses must be trapped by absorption during the relatively short exposure time.
  Venturi devices have also been used for over 100 years to measure fluid flow. In the late 1940s, H.F. Johnstone, William Jones, and other researchers found that they could effectively use the venturi configuration to remove particles from gas streams. Figure 1 illustrates the classic venturi configuration.
context_section_description: The primary maintenance problem for venturi scrubbers is wear, or abrasion, of the scrubber shell because of high gas velocities. Gas velocities in the throat can reach speeds of 430 km/h (270 mph). Particles and liquid droplets traveling at these speeds can rapidly erode the scrubber shell.
  Abrasion can be reduced by lining the throat with silicon carbide brick or fitting it with a replaceable liner. Abrasion can also occur downstream of the throat section. To reduce abrasion here, the elbow at the bottom of the scrubber (leading into the separator) can be flooded (i.e. filled with a pool of scrubbing liquid).  Particles and droplets impact on the pool of liquid, reducing wear on the scrubber shell.
  A common technique to help reduce abrasion is to use a precleaner (i.e., quench sprays or cyclone) to remove the larger and more damaging particles. This also has the added benefit reducing the particle load carried by the liquid.
  The method of liquid injection at the venturi throat can also cause problems. Spray nozzles are used for liquid distribution because they are more efficient (have a more effective spray pattern) for liquid injection than weirs. However, spray nozzles can easily plug when liquid is recirculated. Automatic or manual reamers can be used to correct this problem. However, when heavy liquid slurries (either viscous or particle-loaded) are recirculated, open-weir injection is often necessary.
caption: Figure 7 - Venturi rod scrubber
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