BOLLMAN EXTRACTOR

Presented byPadmaratinam.C.U

3rd year Bio

LEACHING

• Leaching is solid-liquid extraction

• In order to separate a desired solute component from a solid phase, the solid is contacted with a liquid phase

• The two phases are in intimate contact and the solute diffuses from solid to liquid phase resulting in separation

• This is called LEACHING

SOLUTES AND SOLVENTSSOLUTES EXTRACTED BY LEACHING Vegetable seeds like cotton seeds, soybeans,

linseeds, peanuts, rice bran, castor beans

Metal processing industries like copper, nickel, gold and cobalt

SOLVENTS USED FOR LEACHING Petroleum napthals, Hexane, chlorinated

hydrocarbons

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EQUIPMENTS FOR LEACHING• Fixed bed leaching - uses typical fixed bed diffuser or extracter• Moving bed leaching - uses Bollman extractor, Hildebrandt extractor• Agitated solid leaching - counter current leaching using thickeners

Other extractors used include ROTOCEL, FRENCH STATIONARY BASKET EXTRACTOR, KENNEDY EXTRACTOR, CONTINUOUS HORIZONTAL EXTRACTOR

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BOLLMAN EXTRACTOR

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VERTICAL EXTRACTOR

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Description• Bollman extractor – one of basket type machine

• It consists of a vapor tight vertical chamber in which a series of baskets are attached to a chain conveyor

• The baskets are provided with perforations at the bottom

• Dry flakes or solids are added at the upper right side to a perforated basket or bucket in a closed casing05/01/23

Continued…….• As the baskets on the right descend they are

leached by a dilute solution of oil in solvent called half

miscella*

• The liquid percolates downward through the moving baskets and is collected at the bottom as a strong solution or full miscella*

• The baskets moving upward on the left are leached counter currently by fresh solvent sprayed on the top basket

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Continued………

• The wet flakes are dumped as shown in the figure and are removed continuously using a screw conveyor

• Usually the conveyor speed is one revolution per hour and solvent to fresh meal(seeds) ratio is 1

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Recovery of solvent• The recovery of solvent from both the miscella

and the leached seeds or beans is an essential part of the vegetable oil leaching process

• In a typical arrangement, the filtered miscella is passed to an evaporator for removal of solvent followed by final stripping in a tray column to produce solvent-free oil

• The wet seeds are streamed to remove residual solvent and air-cooled

• Ventilated gases from condenser can be to an absorber to recover any solvent

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Continuous Horizontal Extractor

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Kennedy Extractor

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Hildebrandt Extractor