BioBot 20 countertop diesel processor converts waste cooking oil into biodiesel

One difficult aspect of a greener lifestyle involves disposal of used cooking fats.

Most people either pour it down the drain, where it can lurk for years while conspiring to clog your pipes, or pour it in the yard, where it attracts pests of various sorts looking for a free meal. Recycling is obviously a better option, and to this end the BioBot 20 tabletop diesel processor – a (relatively) simple chemical reactor for converting used kitchen oils into biodiesel fuel at home – has been introduced by UK-based company Biobot.

How biodiesel is made

Widely used for a host of purposes, highly-efficient diesel engines power a good fraction of the world’s transportation, industry, and power generation needs. Diesel fuel is denser than gasoline, and has 11 percent larger energy content per liter. Nearly a trillion liters of diesel fuel are used each year worldwide, which releases about 10 percent of the world’s anthropogenic CO2 emissions.

Biodiesel fuels offer a greener alternative to the use of petroleum-derived fuels. Otherwise known as fatty-acid methyl ester (FAME), biodiesel is derived from waste vegetable oils, and is close to carbon-neutral in use. Worldwide, about 20 billion liters of biodiesel are made yearly, with the potential of a fivefold increase without diverting oil away from food uses. Compared to petrodiesel, biodiesel has better lubrication ability, higher cetane rating (less diesel knock), and essentially no sulfur, making it a desirable replacement fuel.

The process of making biodiesel is called transesterification. Vegetable oil is largely made of triglycerides, which contain three fatty acid esters bound to a single glycerine molecule. In the transesterification process, triglycerides are reacted with a mixture of methyl alcohol and sodium hydroxide so that the fatty acid esters break off from the glycerine molecule, and are capped with the methyl group from the methyl alcohol. Potassium hydroxide can also be used, and is preferred by many biodiesel producers.