Biofuels Iso-Conversion

With the process of Biofuels Iso-Conversion (BIC) waste fats and oils can be converted into biofuels. The process starts with a hydrothermal clean-up process to remove contaminants. The first step of the conversion is a catalytic hydrothermolysis where triglycerides and free fatty acids are converted into unbranched and cyclo-alkenes in a water atmosphere at supercritical conditions. This process just takes 2 minutes. For this, the feedstock is mixed with water and is treated with 500-600°C and 200-250 bar in a reactor. The triglycerides are cracked into intermediate products, like organic acids and alkenes and n-alkanes change into cyclo-alkanes (aromatic compounds).

In the next step, a conventional hydrotreatment, olefines are saturated and oxygen is removed with the help of hydrogen and non-precious metal catalysts. Afterwards the products are fractionated in distillation columns. Liquefied petroleum gas (propane, butane), naptha, kerosene and diesel are received.

At present only a pilot plant is in operation, but the process has potential for large scale application.

Another way of biofuel production is co-refining of bio-based oils together with crude oil in conventional refineries. But the composition of the oils and the molecular structure of both oil types differ. For example, the carbon contend of vegetable oil is lower than that of crude oil but the oxygen contend is higher. The exact composition depends on the feedstock. Procedural challenges due to undesired by-products or components like oxygen make the process tricky. Read, amongst others, about the details of the co-refining prozess in Neuling & Kaltschmitt (2018).