KREBS Flue Gas Desulfurization Cyclones for Power Applications

KREBS Flue Gas Desulfurization (FGD) Cyclones: Used to classify limestone ball mill discharge in the reagent preparation area of wet flue gas desulfurization (WFGD) scrubbers in coal fired power plants.

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Flue Gas Desulfurization FGD Hydrocyclones

Krebs Hydrocyclones are used to dewater gypsum from flue gas desulfurization (FGD) in power plants is becoming more significant.  With the technical opportunity of substituting FGD gypsum for natural gypsum in traditional applications such as cement, wall board, and soil conditioners has increased.

Hydrocyclones (cyclones) for the limestone grinding circuit and for gypsum dewatering are typically 4” to 6” diameter cyclones, but occasionally are as large as 10” diameter. Due to the presence of chlorides in the process, cyclone housings are usually of FRP construction, fitted with replaceable gum rubber liners for abrasion resistance.

In using calcium carbonate in wet flue gas desulfurization systems, cyclones can be effective in many process steps.

First: a cyclone can be used to classify and redirect oversized particles of calcium carbonate back to the ball mill for further grinding.

Second: during the formation of gypsum, cyclones dewater and thicken the slurry prior to sending to a dewatering belt.

Krebs gMAX design allows for use of larger cyclones, therefore fewer cyclones.
In applications where chlorides might come into play, hydrocyclones can be manufactured of FRP with replaceable gum rubber liners for abrasion resistance. Hydrocyclone apexes can be manually adjustable gum rubber liners or fixed silicon carbide ceramic inserts. Radial manifold assemblies for the cyclones are fabricated from carbon steel and have spark tested, vulcanized gum rubber and/or chlorobutyl lining. Exposed carbon steel surfaces are epoxy painted for corrosion resistance.

Krebs FGD Products (Pumps, Valves and Cyclones)

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In wet flue gas desulfurization systems, limestone (calcium carbonate) is ground to a powder in a wet ball mill. Krebs cyclones are used to classify the ball mill discharge, returning coarse particles to the ball mill for further grinding. Finely ground limestone (typically 90% passing 45 micron) reports to the cyclone overflow and is stored in a limestone slurry storage tank (at 25-30% solids by weight).

The stored limestone slurry is sprayed counter-currently against the power plant boiler flue gas, absorbing SO2 from the flue gas. The SO2 reacts with oxygen and limestone forming gypsum.

Krebs cyclones concentrate the gypsum slurry from about 15% solids by weight to 45% solids by weight ahead of a vacuum belt filter. The vacuum belt filter produces a filter cake that can be disposed of in a landfill or in some cases, processed to make wallboard. The cyclone overflow is returned to the absorber where fine unreacted limestone is converted to gypsum and fine gypsum crystals grow larger.

Frequently, small diameter cyclones are used to process a portion of the overflow from the gypsum dewatering cyclones. The purpose of this stage of cyclones is to produce a relatively solids free (<1.5% solids by weight) stream that can be sent to a wastewater treatment plant as a chloride bleed from the system.

Krebs FGD Products (Pumps, Valves and Cyclones)

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KREBS hydrocyclones are used in coal mining and wet FGD processes.  Our cyclones or hydrocyclones are often called Hidrociclón, Idrociclone,  Hydrocyklon, Zyklon, and Bagyo, in other languages.  Hydrocyclones are sometimes referred to as separators even though there is a difference the terminology crosses languages and could be pronounced,  Séparateur, Trennung, Panghiwalay, or called Separação or Separazione.  No matter how you pronounce it, FLSmidth Krebs is the leader in hydrocyclones and separators for mining and industrial.

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FLSmidth Krebs, Inc.  (Main Office)
5505 W. Gillette Rd.
Tucson, AZ 85743-9501 U.S.A.

Phone: +1-520-744-8200
Fax: +1-520-744-8300

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millMAXTM Pumps 

Add a millMAXTM pump to your separation process and watch your pumping costs drop.  As a leader in cyclones technology, we make sure your pumping system optimizes your separation requirements.

KREBS gMAXTM Hydrocyclones     

Optimum cyclone performance relies on minimizing turbulence while maximizing tangential velocity. Krebs primary focus is proper design, selection and application of hydrocyclone systems to provide the best product to our customers.

TechnequipTM Valves 

The Technequip knife gate valve is a true bi-directional slurry knife gate valve. It's massive rubber sleeves were designed to seal and withstand the harsh abrasive duty inherent in mining and milling facilities.