REFINING

Turn-key basis contract...

REFINING

Contaminants such as phosphatides, free fatty acids (FFA) and pro-oxidants must be removed from HUM Oil pressing or HUM Extraction and fats before consumption or industrial use. Edible oils and fats are fully refined to improve the flavor, odor, color and stability.

Two processes have been developed for the refining of edible oils and fats, i.e. physical and chemical refining; the decision which process to use depends on the types and qualities of the crude oil to be processed. The names physical and chemical refining come from the process technology used to remove the free fatty acids (FFA) those are responsible for the oil acidity. Physical refining is a process making use of the lower boiling point of the FFA compared to the boiling point of the triglyceride oil. In chemical or alkaline refining, an alkali is used to neutralize the FFA. Chemical refining is the traditional method used in past centuries. The main purpose of chemical refining is to saponify the FFA by an alkaline solution and dilute the resulting soaps in a water phase. These soaps are removed by separators. For small-scale batch processes static separation is used but for continuous processing and large-scale processes, centrifugal separation is used. The neutral oils are subsequently bleached and deodorized. This chemical refining can be used for reliably refining virtually all crude oils, including oils of low quality, with the exception of castor oil.The aim of HUM Refining is to remove the objectionable co-constituents in the oil with the least possible damage to the glycerides and minimal loss of desirable constituents.

It is a sequence of several of the following processes:

  • HUM Degumming, to remove phospholipids or gums from the crude oil.

  • HUM Neutralizing, to remove of free fatty acids, residual phospholipids in degummed oils or all the phospholipids in the crude oils are also removed as insoluble hydrates

  • HUM Bleaching, to remove pigments, metal and soaps from the crude oil.

  • HUM Winterizing, to remove of high temperature melting components present in small quantities.

  • HUM Deodorizing, to remove volatile compounds (mainly ketones and aldehydes) contributing to oil taste and odor, total free fatty acids in physical refining and the residual free fatty acids from neutralized bleached oils.

REFINING
HUM MULTI-LEVEL DEODORIZATION COLUMN
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HUM MULTI-LEVEL DEODORIZATION COLUMN

Deodorization of fats and oils normally consists of steam distillation at elevated temperature under reduced pressure, although nitrogen has also been used. The purpose of this step is to remove volatile compounds (mainly ketones and aldehydes) contributing to oil taste and odor, total free fatty acids in physical refining and the residual free fatty acids from neutralized bleached oils. The deodorization conditions also contribute to the removal of contaminants (light PAH, pesticides, etc.) and to the reduction of color of the oil due to the breakdown of the remaining carotenes at high temperature

STRIKING POINTS

  • High vacuum at each tray of deodorizer

  • Heating of oil to deodorization temperature under vacuum

  • Internal heat exchange at deodorization under vacuum with the help of single or double heaters at semi-continuous process.

  • Processing of edible oil appropriately for such reasons as short stay of the oil containing high free oil acid under high temperatures at scraper column at continuous process.

  • Citric acid dosage that makes compounds with heavy metals in the oil in order to reduce the ratio of the oxidation of deodorized oil.

  • Low pollution of each tribute during product change at semi-continuous process.

  • Low increase rate of trans-isomers during deodorization at low temperatures

  • High quality of deodorized oil for such reasons as low increase ratio of trans-isomers in case the oil, which is scraped under high temperatures, and which contains high free fat acid has an additional scraper column.

  • Deodorization by the circulation systems with high efficiency heat exchange and mammoth pump

  • No time and product loss for frequent product changes at semi-continuous process

  • Heat recovery between incoming and outgoing oil at continuous process.

  • Low oil levels at the levels of deodorization at continuous process

  • High plant efficiency for such reasons as decreased steam consumption during processing of the oil containing high free fat acid with the inclusion of an additional scraper at continuous process.

  • Free fat acids are concentrated in a steam scraper and thus waste water is minimized.

  • De-acidification, as a continuous process integrated with a physical refinery plant does not produce waste as soapstock as in chemical refinery. This means less investment and operational cost.