STORAGE STABILITY STUDIES AND SHELF LIFE DETERMINATIONS OF COMMERCIAL BRAZILIAN BIODIESELS STOCKED IN SUBTROPICAL CONDITIONS IN CARBON STEEL CONTAINERS

摘要

In the present work we have studied the long term storage stability of three different commercial Brazilian methyl esters made from pure soy oil (SoyBlOO) containing TBHQ commercial antioxidant, 65% soybean 35% beef tallow (SoyBTBlend6535) and pure beef tallow (BTBlOOpure). They initially remained stored in HDPE60 L containers sent completely full bythe biodiesel producers and kept stored at thelaboratory premises for 60 days. This preliminary period was meant as most of commercial biodiesel stay in average 60 days stored or travelling before being pumped to the diesel, notably at far end regions of the country. Subsequently 1L carbon steel canisters with a small top hole giving access to the atmosphere were 80%filled with these biodiesels and kept stored for 90 days under sheltered but exposed to air, local heat and humidity conditions.Temperature (T) and relative humidity (UR%) at the open corridor of the laboratory- where the carbon steel canisters were left aside, were on-line monitored during the 90 days testing period. Monthly analyses of aspect, water content, specific gravity, kinematic viscosity, acid number and oxidation stability of the stored biodiesels were also conducted.The main conclusions that were reached are the following: