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Azeotropic vacuum distillation systems for chlorinated solvent

Azeotropic Solvent Distillers for the treatment of distillation residues from automatic degreasing machines

Most automatic degreasing machines, fed by chlorinated solvents, have a recycling cycle of the utilized solvents, by means of an atmospheric pressure distiller which operates in a continuous cycle.  In the distillation process residues, formed by oil, grease, metals, etc., the solvents are still present in a percentage of between 20 and 50%.

This high percentage is due to the thermolability of the chlorinated solvents, not allowing a forced distillation which can cause their acidification.

This has two consequences : a waste of solvent and a high disposal cost of the residue containing a high percentage of solvent. A notable improvement is achieved by vacuum distillation, which enables to lower this percentage to between 5 and 8%. The definitive solution of this problem is obtained by combining vacuum with Azeotropic distillation



In large petrochemical plant, Azeotropic vacuum distillation has been used for many years and it is still one of the most common processes to treat thermolabile solvents, not mixable in water, polluted by liquid contaminants. FORMECO has transferred this sophisticated technology to small size units.  The process consists of a "soft" vacuum distillation for about 70-80% of the polluted solvent. Later on, the concentrated residues present inside the boiler will be treated by a flow of steam which strips the residue part of solvent still present, at a working temperature more than 20% under the critical temperature which causes acidification.


  • Yield of distilled solvent : > 99,7%
  • Solvent contained in the residues : 0,1-0,3%
  • Process residue is able to be disposed off without any charge,
     or reutilized in the original production cycles (ex : cutting oil).


  • Stainless steel AISI 304 boiler, form with a peripheral jacket
    filled with diathermic oil, heated by electrical element.
  • Vapor condenser, cooled by air, with a finned pipe of stainless steel AISI 304.
  • Distilled solvent tank with static water separator incorporated.
  • Steam generator with electrical heating and automatic feeding.
  • Recycling circuit of the process water.


  • Automatic loading of the polluted solvent
  • Automatic unloading of the distilled solvent
  • Automatic unloading of the process residues
  • Electronic program for process control
  • Cartridge filter on the loading line

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2011 Sawyer and Smith Corporation
Last modified: Tuesday July 08, 2014