Methyl Esters Production by Heterogeneous Catalyst Mixtures of CaO/Nb2O5 with Simulation of Analysis of Environmental Impacts

Abstract

The conventional biodiesel process, although it reaches high conversion yields and productivity, faces problems related to the use of homogeneous catalysts. This work aims to study mixtures of calcium oxide (CaO) and niobium oxide (Nb 2 O 5) as the heterogeneous catalyst. It was used a full 2 3 factorial design with four central points to analyze how the mass percentage of the oxides, the molar ratio of reactants, and the reaction temperature affect the conversion yield to methyl esters. The best conversion yield was found near to 89% using 1.8% of catalyst, a 1:36 oil to methanol ratio and at 77 °C as reaction temperature. Finally, it was performed a simplified simulation to compare the heterogeneous catalyst process with the conventional process, and an algorithm to compare the effects of the exit streams of each process would have on the environment. The simulations results display a better performance for the heterogeneous catalyst process studied.

Simple Niobium Catalysts Applied in Reflux and Ultrasound-Assisted Systems for Biofuel Synthesis

“…From catalyst's problems such as those cited, aiming to obtain better activity, many researchers have tried to improve the catalyst's design. [33][34][35][36][49][50][51] Studies using mixed calcium oxide and niobium oxide (CaO-Nb 2 O 5 ) calcined at various temperatures (to produce biodiesel from palm oil and methanol) obtained conversion rates around 98%. 33 Moreover, conversion near to 89% was reported using the same mixture ratio of catalyst, 1:36 oil of macauba (Acrocomia aculeata) to methanol, and at 77 °C as reaction temperature.…”

“…33 Moreover, conversion near to 89% was reported using the same mixture ratio of catalyst, 1:36 oil of macauba (Acrocomia aculeata) to methanol, and at 77 °C as reaction temperature. 34 Silica pellets with a loading of 12% Nb were tested by Tesser et al 35 in esterification and transesterification reaching yields around 90% using soybean oil and methanol at 180 °C. Other mixed catalysts have obtained conversions up to 90% with heating above 225 °C.…”

“…[25][26][27] The application of ultrasound in homogeneously catalyzed biodiesel production processes has been widely investigated [26][27][28][29] and also the effects of ultrasound when solid catalysts are used. 24,[30][31][32] Some published works use niobium compounds as catalysts to produce biodiesel, 23,[33][34][35][36] but none of them under ultrasound-assisted reaction conditions; for this reason, the objective of this research was to test different oil sources and niobium(V) oxide and AmNO as catalysts for biodiesel production with reflux and ultrasound-assisted reaction.…”