Volume 7, Issue 4 (April 2010)
Cold Flow Properties of Biodiesel by Automatic and Manual Analysis Methods
Biodiesel from most common feedstocks has inferior cold flow properties compared to conventional diesel fuel. Blends with as little as 10 vol % biodiesel content typically have significantly higher cloud point (CP), pour point (PP), and cold filter plugging point (CFPP) than No. 2 grade diesel fuel (DF2). Although PP and CFPP may be lowered by treating with cold flow improver additives, these additives do not reduce CP by more than 3–5°C. When stored in moderate temperature climates, biodiesel should be periodically monitored during cooler months. This work examines the use of automated ASTM test methods to reliably monitor CP, PP, and CFPP. Automated instruments have a number of advantages over manually operated apparatus, namely small sample volumes, consistency, speed of analysis, and accuracy of results. Some deviations in data from automated and manual techniques were observed across a diverse set of biodiesel samples. Biodiesel samples were analyzed by subambient differential scanning calorimetry performed at various heating and cooling scan rates for comparison with cold flow property results.