Introduction Principle of operation Particle collection Maintenance operating characteristics Advantages Disadvantages

1. Prepared by,
Asst. prof. Krishna parmar
Environmental Engineering
Diwaliba Polytechnic, Mahuva
Venturi scrubber

2. Contents:
 Introduction
 Principle of Operation
 Diagram
 Particle Collection
 Gas collection
 Operating characteristics of ejector venturi
 Advantage
 Disadvantage
 Maintenance problem

3. Introduction:
 An industrial particulate and Gas
collection device.
 Installed on the exhaust flue gas stacks of large
furnaces.
 A single nozzle is used instead of many nozzles
 Operates at higher pressure and higher injection
rates

4. Principle of operation:
 Scrubbing liquid is supplied to the motive inlet under
pressure.
 As a result of the large drop in liquid pressure across
the nozzle, a high velocity liquid spray exits the
nozzle.
 This atomized liquid provides surface area for
transfer of mass from the gas to the liquid phase and
allows for capture of particulates from the gas phase
due to impaction.
 In addition, the velocity of the liquid spray creates a
negative pressure which pulls gas into the Scrubber.

6. Particle collection:
 larger than 1.0 µm in diameter
 Particle collection efficiency increases with
 an increase in nozzle pressure
 an increase in the liquid-to-gas ratio
 Increases in in pressure drop

7. Gas collection:
 Short gas-liquid contact time
 exhaust gas velocities very high
 removal efficiencies of 95% can be achieved
 Effective if the gas is very soluble or if a very reactive
scrubbing reagent is used

8. Operating characteristics of ejector venturi:
Pollutant Gases Particles
Pressure drop
(Δp)
1.3–13 cm of water 0.5-5 in of water
Liquid-to-gas ratio
(L/G)
7-13 l/m3 50-100 gal/1,000 ft3
Liquid-inlet pressure
(pL)
100-830 kPa 50-100 gal/1,000 ft3
Removal efficiency 95% for very soluble gases 1 µm diameter
Applications Pulp and paper industry
Chemical process industry
Food industry
Metals processing industry

9. Maintenance problems:
 Abrasion problems in the high-velocity areas -
nozzle and throat
 Constructed of wear-resistant materials because of
the high liquid injection rates and nozzle pressures.
 Maintaining the pump that recirculates liquid

10. Advantage:
 Low initial cost
 Small spatial requirement
 A fan is not required to move the gas
 Simultaneous removal of gases and particulates
 No moving parts

11. Disadvantage:
 Large pressure drop
 Sign of erosion when scrubbing abrasive medium