Glycerine from biodiesel

Biodiesel has been produced on an industrial scale in the European Union since 1992. Biodiesel is a renewable fuel produced from vegetable oils such as rape seed oil, sunflower seed oil, soybean oil and also used frying oils (UFO) or animal fats. And even so the production of biodiesel is a complex process indeed, the glycerin that is being distilled during the production process can be used for both technical and pharmaceutical applications.

Bio diesel: various production methods

There are three basic methods to biodiesel production:

  • Base catalysed transesterification of the oil;
  • Acid catalysed transesterification of the oil;
  • Conversion of the oil to its fatty acids and then to biodiesel.

Most of the biodiesel produced today is done with the base catalysed reaction. This catalyst being used splits the oil into glycerine and biodiesel. The glycerin produced at this stage is crude glycerin and is about 80% pure, but still contains contaminants like soap, methanol and water. In order to turn this crude glycerin into technical or pharmaceutical grade product, a or refining purification process must take place.

The glycerin refinement process: technical and pharmaceutical grade glycerin

Crude glycerin is further processed in a distillation unit for obtaining distilled and refined glycerin. During this glycerin refinement process residual organic matter, water, salt, methanol, and odors are removed. The glycerine distillation plant is broadly divided into three main sections: the de-aeration, distillation and bleaching section:

  • The de-aeration loop consists of a re-circulation pump and heat exchanger. The pump circulates the crude glycerine to the de-aeration vessel and feeds de-aerated crude glycerine to the distillation column;
  • The distillation section is composed of various systems consisting of a vaporization system, stripping system, rectification system, pump around system and a scrubbing system;
  • The bleaching section used activated carbon in order to remove colour and odour in the final stage of the purification. Distilled glycerine is cooled to bleaching temperature and then passed through the bleachers. The bleached glycerine is filtered and then finally cooled down to storage temperature.

Glycerine from biodiesel: glycerine chemical structure

Thanks to the activated carbon being used in the final purification process, a pure and odourless type of glycerin is distilled, ready for technical or even pharmaceutical applications:

  • Technical grade glycerin is a refined, high-purity product that is water white with most of its contaminants completely removed.  Technical grade glycerin contains no methanol, soaps, salts, and other foreign matter.
  • Pharmaceutical grade glycerine, as per European Pharmacopeia, is a pharmaceutical grade glycerin suitable for food, personal care, cosmetics, pharmaceuticals, and other specialty applications.

Desotec offers  a range of granular activated carbons specifically designed to provide the optimum pore structure for efficient odour removal combined with the trace colour removal. When desired, Desotec can offer a range of mobile adsorbers to avoid on-site carbon handling or to limit capital investment.

Be sure to contact us for all your questions regarding activated carbon purification solutions!