Laughing Stock Farm, Freeport, Maine

Processing    

The oil comes from the restaurants with food bits, and occasionally other trash.  The burner requires the largest particle size to be no more than 150 microns, so particles larger than this must be removed.  UCO will solidify at about 40F to 50F.  Once it has solidified, or crystallized it must be warmed to at least 110F for the crystals to melt.  The warmer the better for straining.  The discussion below describes the warming and straining of the oil to solve these two problems.

Move Drums Into Greenhouse For Warming - 55 gallon drums are moved with the tractor and material handling forks two at a time.  The drums are set on a  concrete slab, heated by hot water from the UCO boiler, in the greenhouse.  The drums warm to a pumpable strainable liquid in about a day.  The Clean Burn burner uses 30 to 40 gallons/day in winter, so the processing must be done about every three days during January.  

Transfer Oil To Strain Tank - Once warm the oil is cleaned in four steps:

Step 1 - Suck oil from drums by holding the suction tube just below the surface of the oil.  This prevents both the floating and sinking debris from being transferred.  The oil is pulled through a 1/8" basket strainer on the suction side of a 2 HP gear pump.  The strainer basket will need to be cleaned after each drum transfer, or more frequently if the oil has a lot of debris.  The pump discharges the oil into the trough of the strain tank.  See Step 2.  Following this step the drums are cleaned and stored in the empty row for reuse.   

Step 2 - The oil is allowed to strain through the 100 micron screen in the strain tank trough.  It is necessary to wipe the screen periodically to clean the small food bits from the screen.  The strain tank  was fabricated from a used obround No 2 oil tank by cutting off the top, replacing the shell portion of the removed top with perforated steel sheet, and lining this trough with window screen and 100 micron SS screen.  The trough was then set into the reinforced open top of the tank.

Step 3 - The oil should be allowed to settle over night to allow free water and other sediment to collect at the bottom.  This material is removed by opening the bottom valve in the strain tank invert and draining slowly until clear oil is observed.

Step 4 - The clear oil is transferred to the boiler storage tank.   Before making this transfer the basket in the pump suction strainer is replaced with the 100 micron basket and the valves are reoriented to direct the oil to the storage tank.  The 2 HP gear pump is started to transfer the oil. The suction gage will indicate if the 100 micron screen needs to be cleaned.  It is usually possible to transfer 110 gallons without cleaning since the oil has been though a 100 micron screen once before.   

This process is intended to clean the oil to a quality better than required by the burner manufacturer.  My goal is to make the system as reliable as possible, and oil quality is very important to reliability.  All food bits collected during the cleaning process are deposited in our compost pile. 

Oil Use

Send mail to lisa@laughingstockfarm.com with questions or comments about our farm

Send to ralph@rturner.com with questions or comments about our energy project. 

Copyright 2008, Laughing Stock Farm
Last modified: February 01, 2008