The first test batch was made using the world famous Dr Pepper (pat pending) method. The feedstock was virgin rapeseed oil. One litre of the oil was heated to about 50°C in a 2 litre pop bottle and the methoxide (200ml methanol, 5g NaOH) was added. Ensuring the top was screwed down tightly, the bottle was shaken vigorously for about 30 seconds. The temperature was maintained at 50°C for about 2 hours and the shaking was repeated at 30 minute intervals. Separation of the biodiesel form the glycerine by-product was clear and distinct:-

After draining off the by-product, four hot water washes were required to remove all the soap from the biodiesel. The first wash was conducted very gently with about half a litre of hot water, turning the bottle end-for-end about a dozen times. The bottle was left undisturbed until cool, whereupon the soapy water was drained off. Subsequent washes were conducted with gradually more force. By the final wash, vigorous shaking was possible with no danger of an emulsion forming....

From left to right in the above photo:-

• Feedstock - virgin rapeseed oil
• Glycerine by-product with a small quantity of biodiesel on top
• First wash water
• Second wash water
• Third wash water
• Final wash ~ biodiesel on top of clear wash water

Finally, the biodiesel was dried by heating on the stove.

After drying, the finished biodiesel was crystal clear, though slightly darker than expected, perhaps because the drying temperature was a little too high. Overall, a very successful first attempt at making biodiesel.... Now for the 100 litre batch!!

© 2006 Green Valley Biofuels