Monday, April 19, 2010
LL Conference Facility (Hilton Clearwater Beach)
Fast pyrolysis oil is one source of renewable liquid fuels, which is promising in satisfying environmental concerns over fossil fuels. The ASTM D664 method is used to determine the acidic constituents in petroleum products, lubricants, and biodiesel requiring mixtures of propan-2-ol and toluene as solvent. The ASTM method also uses large quantities of solvents for the total acid number (TAN) determination. The ASTM D664 method has been adopted for the determination of TAN for bio-oils data published in literature. However, the properties of fast pyrolysis bio-oils are different from those of petroleum products and biodiesel, because bio-oils are soluble in polar solvents and partially soluble in water whereas petroleum products and biodiesel are insoluble in water and are more non-polar. An alternative method which is more suitable for TAN determination of pyrolysis bio-oil has been developed and validated. Aqueous potassium hydroxide (0.1 M KOH) was used as standard titrant instead of 0.1M KOH in alcoholic solution, and acetone was used as titration solvent instead of mixtures of toluene and propan-2-ol as specified in the ASTM method. Three fast pyrolysis oil samples were tested with the new method and compared with the ASTM method. The results showed that the differences between the TAN obtained using these two methods were less than 5% for all the three samples. In addition, the repeatability of the TAN measurements for the bio-oil using the ASTM method and the new method was investigated. For the studied samples, the repeatability ranged from 3 to 5.6% with the new method, which was slightly higher than the ASTM standard (ranging from 1.1 to 3.8%), but they were both in the acceptable ranges. It was concluded that the new method was simpler and relatively cheaper and more suitable for TAN determination of the pyrolysis oils than the ASTM D664 method.