Cross-flow scrubber

Figure 27. Cross-flow scrubber with three packed beds.

Figure 5. Example of multiple bed cross-flow scrubber.

Cross-flow scrubber—Scrubber in which the gas and liquid flow in perpendicular directions. 

Hansen and Danos (1982) report on experience with a large (18 ft X 8H ft X 46 ft) cross-flow scrubber in a phosphoric acid plant. The scrubber consisted of a spray chamber followed by multiple packed beds of plastic woven mesh. With regard to the spray chamber section of the scrubber, they conclude that a spray nozzle pressure over 60 psig is required to attain 80% fluoride removal efficiency (1.5 transfer units) the amount of spray chamber water should be about 20 to 30 gpm/1,000 acfin and full cone spray nozzles directed countercurrent to the gas flow are preferred. The plastic woven mesh may be irrigated with low-pressure co-current sprays however, the nozzles should be mounted so that they are equidis-... 

Kingman and Sheppard (Air Pollut. Control Assoc. Prepr. 75-30.3) have developed an ioniziug wet scrubber in which the charged mist particles are collected in a grounded, irrigated cross-flow bed of TeUerette packing. Particles smaller than 1 [Lm have been collected... 

Packed-bed scrubbers m be construc ted for either vertical or horizontal gas flow. Vertical-flow units (packed towers) commonly use countercurrent flow of gas and liquid, although cocurrent flow is sometimes used. Packed scrubbers using horizontal gas flow usually employ cross-flow of liquid. 

Cross-file patent searches, 18 243-244 CrossFire Beilstein, 6 19 Cross-flow filtration, 11 383 15 827, 829 in porous pipes, 11 387-388 with rotating elements, 11 383-387 Cross flow model, 21 706 Cross-flow packed scrubber, 26 687-688 Crossflow plates, 6 762-763 Cross-flow screens, 22 282 Cross-flow velocity, 15 725 Crosshead mandrel, in VDC film extrusion, 25 732-733 Cross-lapping, 17 501 Cross-linkable epoxy thermoplastic system (CET), 10 436... 

The waste gas and scrubbing liquid can be put into contact according to the counterflow or cross-flow principle. A counter-flow scrubber, as indicated in Fig. 3, is a... 

The collection of particles is achieved in a countercurrent flow between the water droplets and the particulates. In a cyclonic scrubber, water is injected into the cyclone chamber from sprayers located along the central axis, as shown in Fig. 7.19. The water droplets capture particles mainly in the cross-flow motion and are thrown to the wall by centrifugal force, forming a layer of slurry flow moving downward to the outlet at the bottom of the cyclone. Another type of scrubber employs a venturi, as shown in Fig. 7.20. The velocity of the gas-solid suspension flow is accelerated to a maximum value at the venturi throat. The inlet of the water spray is located just before the venturi throat so that the maximum difference in velocity between droplets and particles is obtained to achieve higher collection efficiency by inertial impaction. A venturi scrubber is usually operated with a particle collector such as a settling chamber or cyclone for slurry collection. 

Cross flow packed scrubber Ap = 0.3 kPa/m of width 1 to 1.5 m width usual water flowrate 2.7 L/m s of horizontal cross-sectional packing size on actual inlet gas flowrate to the packing face of 1 m /m s. 

Continuous, Cocurrent, Counter-current, Cross flow (Not studied detail) in sufficient Miscellaneous (Wetted-wall column, venturi scrubber, turbulent bed contactor etc. 

The third class of scrubber is called cross-flow. This device contacts a horizontally flowing gas stream with a vertically descending liquid flow. Thus, cross-sectional area for gas flow is different from the area for liquid flow. Liquid flow rates can be 40% lower per 1,000 CFM of air than when the gas flow area is the same as the liquid flow area. Even at these reduced liquid rates satisfactory wetting of the tower packing is obtained. 

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