Centrifugal scrubber

Wet scrubber wet cyclone or centrifugal scrubber, c/s, including housing and spray excluding fan, ductwork and instrumentation. FOB cost = 50000 at inlet gas flow rate = 10 Nm /s with n = 0.68 for the range 0.5-35 Nm /s. L-rM ... 

The exhaust air, saturated with water vapor, is first treated in an absorption unit for removal of HjS by routing it through two successive j et scrubbers working with dilute caustic soda solution. Downstream of these, a centrifugal scrubber is installed as an entrainment separator. The sulphide-containing solution rejected from the scrubbers is used to precipitate zinc in the waste water treatment system of the production plant. By products adsorbed on the activated carbon, such as sulphuric acid and elemental sulphur, are removed periodically by water and alkaline extraction. 

The pre-cleaned airstream containing carbon disulfide vapors passes through two or three parallel adsorbers, in which the CS2 is absorbed on a bed of Supersorbon activated carbon. As soon as the adsorbent is saturated it is regenerated by desorbing the solvent with a countercurrent flow of steam. The resulting mixture of water and CSj vapors is condensed and separated in gravity settlers. The recovered CSj is returned to the viscose production without further treatment. The condensed steam is stripped of residual CSj in the centrifugal scrubber and used as dilution water for operation of the jet scrubbers. 

Centrifugal Scrubbers. In a centrifugal scrubber, column design and directed sprays cause droplets and gas to mix in a rising vortex such that centrifugal force increases the momentum of collisions between particles and drops. Thus, smaller particles can be captured, and efficiencies as high as 90 percent can be achieved with particles as small as 5 pm, at pressure drops from 2- to 6-in (50- to 150-mm) water gauge. 

FIGURE 7.4 Process flow sheet of clearing of gas emissions 1 - a Flare 2 - water block 3 - raiser 4 - down-taking duct 5 - Centrifugal scrubber, 6 - scrubber dynamic ... 

FIGURE 8.1 Process flowsheet of clearing of gas emissions (1)—bake roasting a (2)— water block a (3)—raiser (4)—downtaking duct a (5)—centrifugal scrubber, a (6)— scrubber dynamic a (7)— forecastle of gathering of sludge a (8)—hydraulic hitch and a (9)—chimney. 

A hydrostatic precipitator can be described as a centrifugal scrubber or a wet centrifuge. It is essentially a wet dust collector where dust is washed out of the air or gas by the combined action of the intermixing of water and dust-laden gas and of... 

All venturi scrubbers must be followed by an entrainment collector for the liquid spray. These collectors are usually centrifugal and will have an additional pressure drop of several centimeters of water, which must be added to that of the venturi itself. 

Optimum droplet size The idea size of a water droplet in a centrifugal spray scrubber or spray tower to ensure the highest possible cleaning efficiency. 

As pointed out in Volume 1, Chapter 3, a compressor may have any number of stages. Each stage normally contains a suction scrubber to separate any liquids that carry over or condense in the gas line prior to the compressor cylinder (or case for centrifugal compressors). When gas... 

Venturi and orifice scrubbers are simple forms of wet scrubbers. The turbulence created by the venturi or orifice is used to atomise water sprays and promote contact between the liquid droplets and dust particles. The agglomerated particles of dust and liquid are then collected in a centrifugal separator, usually a cyclone. 

SULF-X [Sulfur extraction] A regenerable flue-gas desulfurization process in which the sulfur dioxide is absorbed by aqueous sodium sulfide in a bed packed with pyrite. Ferrous sulfate is produced this is removed by centrifugation and calcined with coke and fresh pyrite. Sulfur vapor is evolved and condensed, and the residue is re-used in the scrubber. Piloted in the mid-1980s. Not to be confused with Sulfex or Sulph-X. 

Both concentrated and dilute waste were sent to a pair of John Zink thermal oxidizers equipped with adjustable venturi scrubbers for removal of particulates prior to stack discharge. Water process waste originating primarily from fermentation sectors was sent to the Carver-Greenfield evaporation system. The evaporator utilized a multistep oil dehydration process and was equipped with a centrifuge, waste heat boiler, and a venturi scrubber. The Clinton Laboratory reported an overall BOD and COD reduction of 90 and 99%, respectively, depending upon the configuration used. 

Gas cleaning may be accomplished either by mechanical methods (such as gravitational settling, centrifugal separation, filtration, ultrasonic precipitators, spray towers, mechanical scrubbers, etc) or by electrical me tbods (such as electrostatic precipitation by Cottrell Method, etc)... 

Cyclone a device for extracting dust from industrial waste gases. It is in the form of an inverted cone into which the contaminated gas enters tangential from the top the gas is propelled down a helical pathway, and the dust particles are deposited by means of centrifugal force onto the wall of the scrubber. 

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. 

For centrifugal compressor supplemental equipment, use Table 8.26. Here supplemental equipment includes such items as inlet suction gas filter-scrubber pressure vessels, suction coolers, intercoolers, and aftercoolers. Air finfan cooling heat exchangers are assumed for the supplemental cost in Tables 8.26 and 8.27. Compressor unit base cost = (base cost from Fig. 8.9 and Table 8.25 or 8.26 Fa) x escalation index. 

---