| Settling Tank |
| When the fuel first comes out of the reactor, it's hot and fully stirred up. The first thing necessary is to allow the fuel to settle. |
| I allow my freshly reacted fuel to settle for 3 full hours. The fuel is hot and will remain so for quite a while so there is no need (in my case) to put a heater into the settling tank while the fuel settles. After the fuel settles, there is a layer of glycerol at the bottom of the settling tank that can be drained off. The layer should be very distinct and you should see it easily through the walls of the poly barrel. |
| Here is a drawing of my settling tank configuration complete with representative layers of fuel and glycerol showing. |
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| Wash Tank |
| The Settling Tank does double duty. It also serves as the Wash Tank after the glycerol is drained off. Washing is necessary to be sure your fuel is as clean as you can get it. Some people do not wash their biodiesel but I'm sure they represent some of the complainers and whiners about the "down side" of biodiesel. My bet is if they bothered to wash their fuel, their complaints and whining would subside and they wouldn't have to change their fuel filters as often. |
| If you follow my Making Biodiesel link, you will see photos of my washing technique using a spray attachment on my garden hose. You will also see the water layer in the wash tank after it has been allowed to settle for 12 hours. The point is, you can use this barrel to do two steps of your biodiesel processing operation: SETTLING and WASHING. |
| This is a drawing of the wash tank after water has been introduced and the water has started to settle out of the fuel. |
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| There is one last thing I would like to mention about this tank. In the biodiesel process, I find that I spend about 2.5 hours with the oil in the reactor, about 2 days with the oil in the settling/washing tank, and about 12 hours or less with the oil in the drying tank. That means the lion's share of the processing time is spent in the settling/washing tank (like those shown above) so, if you want to increase your biodiesel output, it is my humble opinion that you need more settling/washing tanks than you would ever need more reactors or drying tanks. I have two settling/washing tanks and that allows me to cook as much oil as I can collect. This is just an observation I've picked up after doing this for a while and I thought you might like to know in case you are hunting for more water heaters or drying tanks. |
