Biodiesel: A simplified view of my early experience by John Hermans *


Upon purchasing my first diesel van in 2007, my intention was to collect vegetable oil to manufacture into biodiesel. The construction of the biodiesel conversion plant took several days. So little more than a tank full of fossil diesel was used before I became fully independent of the multinationals and their polluting diesel fuel. I have not returned!

The use of vegetable oil is by no means a solution to the impending global fuel shortage. Turning food production areas into fuel production will lead to global food shortage. I am simply using a deep fry oil waste product, and intercepting it before it is collected and refined into biodiesel. The refining process requires the use of methanol at the rate of 20% of the oil volume. My currant biodiesel production and use is minimal, as I will explain.

I found myself making a fresh 350L batch of biodiesel every couple of months. This process occurs over 4 days and takes about eight hours to complete. On day 1, I fill the reactor vessel, course screen and dry the oil, day 2, I heat the oil and reacted it with the methanol, potassium hydroxide mixture, to chemically split the methyl esters (biodiesel) from the glycerine. Then on day 3, the glycerine is drained off and the biodiesel is mist spray washed with water, day 4, it is dried with an aquarium bubbler, and dry air is bubbled up through the oil container. This entire process, although cheap (30c per treated litre), still requires the use of a fossil fuel based additive, methanol at 20% of treated oil, and a caustic additive.

After around a year of biodiesel making, I researched the option of running the motor on straight veggie oil (SVO). This change was a positive forward step. Since the vehicle has been changed to a two-tank system (original 60 L tank with biodiesel and extra 120L tank for SVO) my oil processing has been reduced in both time and cost. I now only make a batch of biodiesel every 6 months, as I use 90% of fuel oil as SVO, which only requires course straining and bubble drying.

The Biodiesel production process requires the use of highly volatile, fossil methanol (20%), and highly corrosive Potassium Hydroxide (KOH @ approx. 20 g/L).  So any conversion plant needs to be safely located away from residences and children, preferably, simply a lean to, on a farm shed. 

*John is a regular contributor to RENEW magazine and president of the Gippsland Environment Group.