Evaluation of Two Purification Methods of Biodiesel from Beef Tallow, Pork Lard, and Chicken Fat

摘要

Beef tallow methyl esters (TMEs), pork lard methyl esters (LMEs), and chicken rat methyl esters (CMEs) were produced, purified, and characterized to evaluate their quality and compare two purification methods: (1) conventional neutralization, water washing, and drying and (2) purification using cationic exchange resins. Also, B20 blends [20% biodiesel (v/v) mixed with petroleum diesel] were characterized and evaluated. The conventional alkali-catalyzed transesterification process was used, with methanol as the reagent and KOH as the catalyst, yielding 76.8, 90.8, and 91.5% (w/w) CME, TME, and LME, respectively. The ester content of these biodiesels was below 96.5% (w/w), and the kinematic viscosity was high (ranging between 4.84 and 6.86 mm2/s), which poses restrictions to their use as fuel in vehicle engines, especially in low-temperature climates. Although it is not possible to use 100% biodiesel produced from these animal fats, blends of 20% biodiesel are viable with some advantages, such as the improved cold-flow properties [cold filter plugging point (CFPP) below - 6 °C], lower kinematic viscosity (from 3.10 to 3.28 mm2/s), and higher heating value of the mixture (about 44.6 MJ/kg). Results also show that the resin purification helps to reduce biodiesel acidity and kinematic viscosity, while conventional water washing followed by adsorbent drying and filtration gives better results regarding water and alkaline metal (Na + K) content