Anhydrous Ethyl Alcohol is produced by Dehydration of Hydrous Ethyl Alcohol by a PSA process using molecular sieves. Molecular sieves are so chosen that they have a property of exclusively adsorbing water molecules but will reject (allow to pass through) ethanol molecules being too large in size. Under the proper circumstances the sieves will adsorb water from Hydrous mixture of Ethanol & water & will leave Alcohol stripped off water.

Plant produces Ethyl Alcohol, of 99.8% v/v from 94-95% v/v Ethyl Alcohol, water mixture Anhydrous ethyl Alcohol is used for Industrial Chemical applications as well as gasoline additive.

Feed stock – a mixture of Ethyl Alcohol & water is preheated in a feed economizer & further vaporized in vaporizer. Vaporizer is heated by hot thermic fluid circulation with a Thermopac. Hydrous Ethyl Alcohol vapor passes down a Battery of molecular sieves column – 3 nos. One of the column is in adsorption mode while the other two are in regeneration mode. The sequencing is controlled by a PLC which automatically performs necessary switching of the columns from the adsorption to regeneration & visa versa on a regular basis to perform the drying process efficiently. As the vapor passes down the column, water is adsorbed in the pores of the sieves & Anhydrous Ethyl Alcohol passes.

Dried product Alcohol leaves the adsorption sieves column & is condensed back to liquid phase & cooled to ambient temp in the product cooler.

During regenerating mode, the adsorbed water is removed by applying vacuum to the column under regeneration.

The stream generated during the regeneration step, containing all of the water from the saturated bed & some Ethyl Alcohol as well, is taken to recovery column. Here the weak Alcohol is concentrated to 94-95% strength & is recycled back to the system while water leaves the recovery column from its base.

With PLC based control system, critical process parameters are constantly monitored & required control action is decided accordingly through pneumatically controlled valves.

Because of high cost of molecular sieve & requirement of instrument for automation the initial cost of plant based on use of molecular sieve is rather high but the conversion cost of Rectified Spirit to Anhydrous Ethanol is very economical as compared to Aezotropic distillation system. The initial high cost is recovered within a year. Thus molecular sieve system has conspicuous merits. It has become more popular in Brazil & U.S.A.


The plant is based on vapor phase molecular sieve dehydration technology.

  • - Rectified Spirit (95%) Alcohol both Plain and Denatured.
  • - Absolute Alcohol(Ethanol) 99.8% minimum both Plain & Denatured
  • - Extra neutral Alcohol (95-99.8)%

SR No Name Availability Seasonality Import Restrictions (If any)
1 Rectified Spirit (RS) Ex Stock Through Out the Year No
2 Special Denatured Spirit ( SDS) Ex Stock Through Out the Year No
3 Extra Neutral Alcohol (ENA) Ex Stock Through Out the Year No
4 Absolute Alcohol (AA) Ex Stock Through Out the Year No
5 Denatured Absolute Alcohol Ex Stock Through Out the Year No
6 Denaturants & Bittrents Ex Stock Through Out the Year No