It was stated by that the microemulsion
process is developed and used to solve the problem
regarding high viscosity of vegetable oil. A micro-emulsion
is made by blending the vegetable oil with suitable solvents.
Solvents that have been used and studied previously are
methanol, ethanol, and 1-butanol. The disadvantages of this
process are that it can result in heavy carbon deposits and
incomplete combustion.