The new ASTM D6751 cold Soak Filtration test is leaving many Biodiesel producers and consumers out in the cold. In Response new products are presenting new technology designed specifically to ensure that biodiesel products conform to the ASTM standard for cold flow properties.
What is this new test all about? The American Society for Testing of Materials has recently added the cold soak filtration analysis and defined it as: the time in seconds that it takes for cold soaked biodiesel to pass through two 0.8 micron filters and the amount of particulate matter expressed in milligrams per (mg/l) collected on the filter. Why is this new test important? The problem is when biodiesel is stored in temperatures below 40 degrees F. for extended time periods, certain particles within the fuel solution will fall out of the fuel to the bottom of the storage tanks. This particle fall out will build into an ever thickening layer of build up at the bottom. Generally the colder the temperature and the longer the fuel stays at that temperature, will induce even more material to fall out.
The material has the potential to plug filters, increase maintenance cost and at worst shut down engines. What is this material that falls out? It has to do with the feedstock that the biodiesel was produced from. Feedstocks, especially those produced with used cooking oils (UCO), waste vegetable oils (WVO), yellow grease or animal fats (Tallow) will produce high levels of fall out materials. These materials can also be caused by incomplete removal of glycerin, soaps, waxes, or resins during the Transesterification process.
In response to this problem companies such as 70CentsaGallon are offering in-expensive options like Cold Clear. This system uses a three-stage bank of housings in a combination of filtration, adsorption and absorption principles to capture the materials that can cause plugging or crystallization in biodiesel fluids. This treatment system is solving the cold soak filtering dilemma in B-100 biodiesel and other biodiesel blends in a single pass while having little loss in yield.
This new ASTM test is a positive step in making biodiesel a more consistent consumer friendly product with the help of new technologies like Cold Clear.