Biodiesel is most commonly produced through a process called transesterification, which involves taking naturally occurring carbon chain molecules, known as triglycerides, found in such feedstocks as seed oils and animal fats, and converting them into methyl esters, which is the chemical term for biodiesel. This is achieved by reacting triglycerides and free fatty acids with an alcohol, such as methanol.
Traditional biodiesel production typically utilizes feedstock with very low free fatty acid (“FFA”) content, generally 1% or lower, because the presence of FFA during the transesterification process will produce soaps and emulsions, which prevents the separation of biodiesel from glycerine. Feedstocks with lower FFA content have higher costs.
FFAs can also be converted into biodiesel, but through a process called acid esterification. However, due to lengthy conversion times, low conversion rates and therefore poor economics when using traditional methods of acid esterification, the process is rarely used. In fact, feedstocks are usually pre-treated to remove the FFAs, thereby reducing yields and increasing production costs.
In comparison, BIOX’s patented production process converts first the FFAs (by way of acid esterification) and then the triglycerides (by way of transesterification) , through the addition of a co-solvent, in a two-step, single phase, continuous process at atmospheric pressures and near-ambient temperatures, all in less than 90 minutes, rather than the several hours or even days under conventional processes, with the highest possible conversion yields. The co-solvent is then recycled and reused continuously in the process.