Issue 8/2014 - Biodiesel cleaning process using calcium oxide catalyst

A team led by researchers at the University of
Córdoba in Spain has used a basic multiphase catalyst to produce a mixture of conventional fatty acid methyl esters (FAME, or conventional biodiesel) and monoglycerides (MG) (with a molar ratio of 2:1)
that they call "second-generation biodiesel.
" This process converts glycerol, a by-product of conventional ester transfer reactions, into FAME and MG.


According to the team's paper published in the journal Fuels, FAME/MG blends produced using calcium oxide alkaline heterogeneous catalysts are of the same nature as biodiesel blends produced using more expensive lipases, while significantly reducing pollutant emissions and improving conversion efficiency
.

It has been found that in the conventional ester transfer process, by-product glycerol will be generated regardless of the ratio of reaction conditions, resulting in a large number of performance losses and contamination problems
.
The researchers found that although calcium oxide catalysts have lower catalytic activity than traditional complete ester transfer catalysts such as sodium hydroxide or potassium hydroxide, they are well suited for partial ester transfer of triglycerides to avoid by-products
.

If used to produce traditional biodiesel, calcium oxide needs to play a catalytic role in high temperature and high pressure environments, but the team found that the molar ratio of methanol and oil is 6:1, adding 7% calcium oxide, and the reaction temperature is 65 °C to generate biodiesel blends
at atmospheric pressure.
The activity of the calcium oxide catalyst can be used repeatedly for 20 production cycles
.
(Xiaohua)