MHF is produced by physically blending and microemulsifying various ratios of plant oil with diesel fuel in the presence of an additive, which could be composed of cetane enhancers, viscosity reducers and/or emulsifiers. A blend of 30% plant oil and 70% diesel fuel is called MHF30 while a blend of 50% plant oil and 50% diesel fuel is called MHF50 and so forth. Different types of plant oils can be used such as palm oil, jatropha oil, coconut oil and others as well as recycled mixed waste cooking oil. Figure 6.1 shows a schematic process flow diagram for the production of microemulsified hybrid fuel. Plant oil and diesel in the desired ratio are pumped from their respective storage tanks through micro-filters (around 10 microns) into the MHF machine where they are mixed together with a small amount of proprietary additive (less than 1%). The mixture is then recirculated through a proprietary reactor for about two hours before it is discharged into a service tank where it remains quiescent to allow the removal of any residual sediment. The supernatant liquid is then again pumped through micro-filters (around 5 microns) before being sent into the final storage tank ready for delivery and use.
The core of the technology is the ability to produce particles in the range of 1-2 microns in size compared to the conventional technology that produces particles in the range of 10-20 microns. By producing much smaller and more uniform dispersion, the combustion efficiency is greatly enhanced resulting in much improved engine performance. When the particles of the fuel spray are large, the combustion is less efficient, and when the particles are of varying sizes, the power delivered is lower since the fuel particles do not burn at exactly the same time. Actual fuel injection spray tests show that the spray produced using palm oil MHF50 have very fine droplets or particles.
Palm oil is the preferred blending material because of its ready availability and price advantage. However, once jatropha oil becomes available in sufficient quantities, it will be the preferred blending material. Depending on the actual prices of plant oil and diesel fuel in a given locality, the price of MHF can be competitive with diesel fuel. Since the technology does not involve chemical processing, the total processing cost is generally much lower compared to transesterification. In addition, since glycerin is not removed from the plant oil, the heating value of the resulting product is generally higher compared to the equivalent methyl ester produced through transesterification.