Biodiesel production from high acid value waste frying oil catalyzed by superacid heteropolyacid

Abstract

Transesterification of waste cooking oil with high acid value and high water contents using heteropolyacid H3PW12O40 x 6H2O (PW12) as catalyst was investigated. The hexahydrate form of PW(12) was found to be the most promising catalyst which exhibited highest ester yield 87% for transesterification of waste cooking oil and ester yield 97% for esterification of long-chain palmitic acid, respectively. The PW12 acid catalyst shows higher activity under the optimized reaction conditions compared with conventional homogeneous catalyst sulfuric acid, and can easily be separated from the products by distillation of the excess methanol and can be reused more times. The most important feature of this catalyst is that the catalytic activity is not affected by the content of free fatty acids (FFAs) and the content of water in the waste cooking oil and the transesterification can occur at a lower temperature (65 degrees C), a lower methanol oil ratio (70:1) and be finished within a shorter time. The results illustrate that PW12 acid is an excellent water-tolerant and environmentally benign acid catalyst for production of biodiesel from waste cooking oil.

Valorization of Waste Cooking Oil into Biodiesel over Heteropolyacids Immobilized on Mesoporous Silica — A Kinetic Study

“…HPAs and HPAs supported on different supports have been used as acid catalysts for biodiesel production [44][45][46][47][48].…”

Production of Bio-Hydrogenated Diesel by Hydrotreatment of High-Acid-Value Waste Cooking Oil over Ruthenium Catalyst Supported on Al-Polyoxocation-Pillared Montmorillonite

“…It is presumed that 100-140 kt waste cooking oil from the household sector is discarded every year in Japan [5]. Recently the production of bio-diesel from waste cooking oil has been studied worldwide [6][7][8][9].…”

“…However, base catalysts lose their activity in the transesterfication of high-acid-value waste cooking oil as they react with free fatty acids to form soap. Acid-catalyzed transesterification is much slower than base-catalyzed although some new acid catalysts have been developed [6]. In general, a complex two-step process has to be used for the FAME production from high-acid-value waste cooking oil: using acid catalysts to convert free fatty acids in the first step and base catalysts to convert triglycerides in the second step.…”

Production of Petroleum – like Fractions from Waste Cooking Oil

“…Currently, transesterification is the primary route for producing biofuels (particularly biodiesel) from plant oils [21][22][23][24]. Although this process has many benefits, however, it shows several disadvantages [25,26] .…”