Light yellow to dark brown, viscous liquid
Flexi Bag, 23.5 MT/20 FCL
Crude glycerine is a viscous liquid with a naturally sweet taste and light yellow to dark brown in color. It is the impure form of refined glycerine. Crude glycerine is derived from both natural and chemical feedstocks. Glycerine occurs in combined form in vegetable oils and fats as triglycerides. It is also found in animal fats. Crude glycerine is obtained as a byproduct from the biodiesel manufacturing plant and oleochemical industries.
Emphasis has been placed on the usage of renewable energy, resulting in an increase in the production of biodiesel. As crude glycerine is a byproduct in the production of biodiesel, there is a corresponding increase in the production of crude glycerine. Crude glycerine specification commonly includes 80% glycerine and the rest is made up of impurities such as methanol, soap, catalyst, salts, non-glycerine organic matter, and water.
The degumming process of vegetable oil involves the removal of phosphatides from vegetable oil by centrifugation. Water is added in the mixture to allow the precipitation of phosphatides dissolved in oil. The precipitated phosphatides become heavier in mass due to the high water content absorbed. The centrifugation process allows phosphatides to migrate to the water phase; therefore, removing impurities in the oil. Degumming is required to refine the quality of the vegetable oil and allows longer storage time.
The vegetable oils undergo deacidification through a series of solvent extraction processes. The initial vegetable oil is mixed in methanol by agitation. The existing free fatty acid in the oil will preferably dissolve in methanol and decrease the concentration in the oil. As free fatty acid is the cause of the oxidation and unpleasant scent of the oil, it is essential to remove the compound from the oil to promote storage time and refining.
The deacidified oil is decomposed through a process called hydrolysis. The process utilizes water to break down the chains of triglycerides into glycerol/glycerine and fatty acid under high temperature and pressure. In this step, glycerine becomes available for extraction and undergoes further refining.
Crude glycerine has a high metabolizable–digestible energy ratio that is almost identical to soybean oil. The source of energy from glycerine is used to feed cattle and other herbivorous animal farms.
The remaining crude glycerine is utilized as an intermediary chemical through thermo-chemical conversions. The product propylene glycol is manufactured from crude glycerine through a process called hydrogenolysis. Propylene glycol is utilized as an antifreeze compound and as a fuel additive in methanol-fueled vehicles.
Crude glycerine is able to be used in composting through various biological conversions. The product succinic acid is produced from the fermentation process of crude glycerine with the bacterium Anaerobiospirillum succinic. In addition, further research has suggested that algal fermentation may convert crude glycerine into omega-3 polyunsaturated fatty acid.