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How It Works
A venturi scrubber accelerates dirty gas through a narrow throat where scrubbing liquid is injected. The high-velocity gas atomizes the liquid into fine droplets that collide with and capture particulate matter. The pressure drop across the throat is the primary design parameter -- higher pressure drops yield better collection efficiency but cost more energy.
The simplified Calvert equation relates pressure drop to gas throat velocity and the water-to-gas volume ratio: Pdrop = 10−6 × v² × L.
Example Problem
A venturi scrubber operates with a gas throat velocity of 12,000 cm/s and a water/gas ratio of 1.3 L/m³. What is the pressure drop?
- Pdrop = 10−6 × 12,000² × 1.3
- Pdrop = 10−6 × 144,000,000 × 1.3
- Pdrop = 187.2 cm water
Frequently Asked Questions
How does a venturi scrubber remove particles?
The high-velocity gas in the throat atomizes the scrubbing liquid into tiny droplets. Inertial impaction causes particles to collide with these droplets, which are then separated from the gas in a downstream cyclonic separator or mist eliminator.
What is a typical pressure drop for a venturi scrubber?
Pressure drops typically range from 25 to 250 cm of water column. Low-energy scrubbers (25–50 cm) collect coarse particles above 5 μm, while high-energy units (150–250 cm) can capture sub-micron particles.
When should I use a venturi scrubber instead of a baghouse?
Venturi scrubbers excel when the gas stream is hot, humid, corrosive, or contains sticky particles that would blind a fabric filter. They also simultaneously remove some gaseous pollutants. Baghouses are better for dry, moderate-temperature gases with very high efficiency requirements.
Related Calculators
- Cyclone Calculator -- pre-separate coarse particles before the scrubber.
- Electrostatic Precipitator Calculator -- alternative dry collection technology for fine particles.
- Atmospheric Dispersion Calculator -- model emissions after scrubber treatment.
- Fluid Pressure Calculator -- calculate pressure drop across the scrubber throat.
- Pressure Unit Converter -- convert scrubber pressure drop between inches of water, Pa, and psi.