Techno-Economic Assessment of an Alternative Process for Biodiesel Production from Feedstock Containing High Levels of Free Fatty Acids

Abstract

The technical and economic feasibility of an alternative process for biodiesel production from residual oil and fats (ROF) was compared to two cases of the conventional two-step alkali-catalyzed process. A reliable set of thermophysical properties, kinetic data, and a rigorous thermodynamic modeling were used in the simulations. The alternative process employed liquid−liquid extraction to separate the free fatty acids from triacylglycerols, with methanol as the solvent. Both processes were found to be technically feasible based on a design specification of 99.65% esters for the product. The alternative process proved to be slightly more economically viable than the conventional process based on the selected economic indicators and thus is a promising alternative for biodiesel production from ROF.

Optimization of the Extraction of Free Fatty Acids Applied to Biodiesel Production

“…In order to optimize the FFA separation from ROF using a LLEx process, initially a 2 3 full factorial design (FFD) including a central point was carried out. The parameters investigated were T, N and S/F as presented in Table 1 and in Figure 1, where FFD 1 (design 1) and FFD 2 (design 2) differ only in the levels used for N. The levels for N and S/F were chosen based on the process simulation of an alternative process to produce biodiesel applying FFA separation from ROF by LLEx (Albuquerque et al, 2016) while temperature levels were defined by the temperature range from the available LLE data.…”

“…Following Seider et al (2009), the heat exchangers were designed as a double-tube type (area less than 150 ft 2 ) or shell and tube type (area greater than 150 ft 2 ). A detailed description of the design procedure can be found in Albuquerque et al (2016).…”

“…Operation costs included utility costs (vapor or water in heat exchangers) and solvent (methanol) cost and were calculated as presented by Albuquerque et al (2016). The methanol cost was calculated multiplying the price of methanol ($0.85/kg) by the methanol mass flow rate fed plus a factor to account for the solvent make-up, 7.4% and 8.5% for cases 1 and 2, respectively (Albuquerque et al, 2016). The raw material (ROF) cost was not included in the operation costs to avoid masking since it is significantly higher than the capital and other operation costs.…”

“…On the other hand, alternative processes employing the FFA separation from the oil have proven to be economically more attractive (Albuquerque et al, 2016). FFA separation is widely used in the food industry to produce edible oils.…”

Efeito Da Seletividade Sobre as Operações E Configuração Da Torre De Extração No Sistema Metil Oleato, Metanol, Glicerol E Água

“…Os fluxogramas das colunas extratoras com e sem refluxo foram simulados no software Aspen Plus® V8.0 e são mostrados nas Figuras 1a e 1b, respectivamente (Holland, 1975). Para a simplificação das simulações, a composição da carga de alimentação da coluna de extração foi definida com base nos componentes mais relevantes obtidos após a recuperação de metanol por destilação na unidade de transesterificação (Albuquerque et al, 2016). A Figura 1 mostra os componentes envolvidos nesta corrente (metil oleato, metanol e glicerol), assim como da corrente de solvente (água) com suas respectivas condições operacionais.…”