Some of our users have had questions regarding the use of highly saturated fats, hydrogenated oils, and tallows in the BioPro™ biodiesel processors. To make a long story short, they can be processed in a very similar manner to any other fat or oil, with a few minor differences.
The most obvious difference between tallow and vegetable oil is the gel point of the feedstock. Because tallows are solid at room temperature, they can often be difficult to load into the machine. In the machine at our testing facility we have had to literally use a shovel to scoop solidified animal fats into the test machine for processing. A user may find it easier to use a heater to liquefy the animal fats in their storage vessel so that these may be pumped into the machine. This gel point difference may also affect the level of contaminants such as water and debris in the feedstock as well. As can be imagined, many contaminants that would have naturally settled to the bottom of a liquid feedstock will stay suspended in a feedstock that has solidified.
Therefore extra care must be taken to filter contaminants and remove water that could be in tallow based feedstock. The owner’s manual provides clear instructions on how use the BioPro to effectively clean and dry your feedstock. Please note that as with oil from vegetable origin, we recommend that tallow processed in a BioPro have a FFA level of less than 5% and a water level of .2% or less.
The main stirring prop in the 190 is meant to stir liquids. If the main stirrer is turned on in the BioPro while it is filled with solidified feedstock, the excessive resistance is likely to blow the fuse to the stir motor. If the BioPro is filled this solidified feedstock we recommend turning on the manual heater switch until all of the feedstock is melted before turning on the manual main stir switch or starting the automatic process.
Note that fuel made from saturated feedstocks will tend to have a high gel point as well. Fuel made from beef tallow will often have a gel point of about 50 or 60 degrees F. This could be problematic if the user is attempting to utilize this fuel during cold weather or to purify it in a drywash column in cold weather. Springboard sells The Springflow 250 fuel preheater if you would like to be able to use this fuel in a greater temperature range. Finally, the user may find it beneficial to use warm water during the wash cycle of the machine when washing fuel made from tallow. This helps to ensure that the wash cycle runs smoothly, without any complications caused by cold water mixing with high gel point fuel.