This last weekend we accomplished several project goals. About 10 members of the biodiesel group congregated in my back yard on Saturday to help brew the first full batch of biodiesel in the processor, and the operation went quite well.
It was a cool morning, so the oil started at about 60 degrees, so I used the centerfuge to heat and filter the oil until it was was 120 degrees which took about 2.5 hours. Robin is currently building us a small heater for the system so we can more precicely control the temperature without the use of the centerfuge. The rest of the process went well, although it took a long time to get the lye to dissolve in the methanol.
That being said, we decided to discuss the design of the methoxide mixing system, and I picked up a damaged washing machine for its pump and motor. We took apart the machine and tested its functionality (which was fine), but we decided that we will need to make some adjustments to the plumbing and wiring to make it ideal for a methoxide mixing system. In the next few weeks we will build the mixer and test it.
To avoid the problem of the glycerol congealing, I drained the glycerol in stages (every 30 minutes or so). The glycerol flowed well, although to avoid this problem in the future and to improve the soap-making prospects, we are going to investigate the use of KOH instead of NaOH as a catalyst. KOH will cost more than double (adding $.07/gallon to the final product cost), but it won't congeal with poor oil, and it will produce a liquid soap which is easier to work with than the soap bars from the lye byproduct. Keep checking here to see our progress on this task.
After the biodiesel was finished reacting and draining, I added .5% magnesol by weight (about 10 cups worth), and I mixed it completely. I then ran the centerfuge for 1.5 hours to clean out the magnesol. To run it optimally, I actually used the porportioning valve to decrease the pressure to 40psi. I did this because the normal 90psi that the pump produces causes the centerfuge to spin at very high speeds and eventually it slows (most likely due to friction). It seems that running it at 40psi alleviates this issue.
I had to clean the centerfuge once and it was obvious that it needed cleaning because I could hear that it was slowing down and almost stopped. When I took it apart, it was almost completely full of magnesol, so it performed its task properly and it was pretty easy to clean. Once I have drained the tank and I have taken apart the final filter, I will get a better idea of how much magnesol the centerfuge didn't remove. So far, it looks like adding more centerfuges will significantly increase the speed and contamination capacity of the filtering system. Our 1.5 HP pump should be able to drive several centerfuges at 40 psi if that is necessary. I am also testing the filtration waste product as a fertilizer in my garden. Keep posted for those results as well.