Light yellow to dark brown, viscous liquid
Flexi Bag, 23 MT/20 FCL
Crude glycerine, possessing a naturally sweet taste and exhibiting a viscous texture ranging from light yellow to dark brown, represents the unrefined state of glycerine. It originates from both natural and chemical feedstocks, primarily existing in vegetable oils and fats as triglycerides, and is also present in animal fats. As a byproduct of biodiesel production and oleochemical industries, crude glycerine is obtained during these processes. The growing emphasis on renewable energy sources has led to an increased production of biodiesel, consequently resulting in a rise in crude glycerine production. Typical specifications for crude glycerine include approximately 80% glycerine, with the remainder comprising impurities such as methanol, soap, catalyst, salts, non-glycerine organic matter, and water.
Degumming is a pivotal stage in refining vegetable oil, involving the precise removal of phosphatides through centrifugation. Water is introduced to facilitate the precipitation of phosphatides dissolved in the oil, transforming them into weightier masses due to absorbed water content. The ensuing centrifugation allows these phosphatides to migrate to the water phase, effectively eliminating impurities from the oil. This crucial process not only refines the quality of vegetable oil but also extends its storage life.
Deacidification takes the spotlight next, employing a series of solvent extraction techniques on vegetable oils. The initial step involves agitating the vegetable oil in methanol, causing free fatty acids to preferentially dissolve in methanol, thereby reducing their concentration in the oil. As these free fatty acids are responsible for oil oxidation and unpleasant odors, their removal is imperative to enhance storage time and facilitate further refining.
The deacidified oil then undergoes a transformative stage known as transesterification/saponification. This intricate process, conducted under high temperature and pressure with the aid of water, dismantles the triglyceride chains into glycerol/glycerine and fatty acids. Notably, this step makes glycerine accessible for extraction, setting the stage for additional refinement.
The high metabolizable–digestible energy ratio of crude glycerine is approximately the same as that of soybean oil. Glycerine serves as a source of energy for farms that raise cattle and other herbivorous animals.
Remaining crude glycerine can be converted into an intermediate compound via thermochemical changes. Propylene glycol is produced via hydrogenolysis, which converts crude glycerine into its final form. Propylene glycol, also referred to as glycol, is used in methanol-powered cars as an antifreeze ingredient in addition to a fuel additive.
Crude glycerine has the potential to be utilized in composting through a range of biological processes. The fermentation of crude glycerine with the bacterium Anaerobiospirillum succinic results in the production of succinic acid. Additionally, current research suggests the prospect of algal fermentation converting crude glycerine into omega-3 polyunsaturated fatty acid.