Venturi scrubber

Introduction
Principle of operation
Particle collection
Maintenance
operating characteristics
Advantages
Disadvantages

1. Prepared by, Asst. prof. Krishna parmar Environmental Engineering Diwaliba Polytechnic, Mahuva V enturi 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. I nstalled 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 .

5. 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

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

7. Operating characteristics of ejector venturi : Pollutant Gases Particles Pressure drop ( Δ p) 1.3–13 cm of water 0.5-5 in of water Liquid-to-gas ratio (L/G) 7-13 l/m 3 50-100 gal/1,000 ft 3 Liquid-inlet pressure (p L ) 100-830 kPa 50-100 gal/1,000 ft 3 Removal efficiency 95% for very soluble gases 1 µm diameter Applications Pulp and paper industry Chemical process industry Food industry Metals processing industry

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

9. 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

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

11. Thank you