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Gas phase decarboxylation of hydrolyzed free fatty acid (FFA) from canola oil has been investigated in two fix-bed reactors by changing reaction parameters such as temperatures, FFA feed rates, and H2-to-FFA molar ratios. FFA, which contains mostly C18 as well as a few C16, C20, C22, and C24 FFA, was fed into the boiling zone, evaporated, carried by hydrogen flow at the rate of 0.5-20 ml/min, and reacted with the 5% Pd/C catalyst in the reactor. Reactions were conducted atmospherically at 380-450 °C and the products, qualified and quantified through gas chromatography-flame ionization detector (GC-FID), showed mostly n-heptadecane and a few portion of n-C15, n-C19, n-C21, n-C23 as well as some cracking species. Results showed that FFA conversion increased with increasing reaction temperatures but decreased with increasing FFA feed rates and H2-to-FFA molar ratios. The reaction rates were found to decrease with higher temperature and increase with higher H2 flow rates. Highly selective heptadecane was achieved by applying higher temperatures and higher H2-to-FFA molar ratios. From the results, as catalyst loading and FFA feed rate were fixed, an optimal reaction temperature of 415 °C as well as H2-to-FFA molar ratio of 4.16 were presented. These results provided good basis for studying the kinetics of decarboxylation process. [ABSTRACT FROM AUTHOR]

Abstract: Computational Fluid Dynamic (CFD) modeling of a continuous countercurrent hydrolysis process was performed using ANSYS-CFX. The liquid properties and flow behavior such as density, specific heats, dynamic viscosity, thermal conductivity, and thermal expansivity as well as water solubility of the hydrolysis components triglyceride, diglyceride, monoglyceride, free fatty acid, and glycerol were calculated. Chemical kinetics for the hydrolysis reactions were simulated in this model by applying Arrhenius parameters. The simulation was based on actual experimental reaction conditions including temperature and water-to-oil ratio. The results not only have good agreement with experimental data but also show instantaneous distributions of concentrations of every component in hydrolysis reaction. This model provided visible insight into the continuous countercurrent hydrolysis process. [Copyright &y& Elsevier]

Abstract: Thermal hydrolysis of triglycerides to form free fatty acid (FFA) is a well-established industry practice. Recently, this process has been employed as a first step in the production of biofuels from lipids. To that end, batch and continuous hydrolysis of various feedstocks has been examined at the laboratory scale. Canola, the primary feedstock in this paper, camelina and algal oils were converted to high quality FFA. For the different reaction temperatures, the continuous hydrolysis system was found to provide better yields than the laboratory batch system. In addition, CFD simulation with ANSYS-CFX was used to model the performance and reactant/product separation in the continuous, counter-flow reactor. The effects of reaction temperature, water-to-oil ratio (ratio of water and oil volumetric inflow rate), and preheating of the reactants were examined experimentally. Optimization of these parameters has resulted in an improved, continuous process with high mass yields (89–93%, for reactor temperature of 260°C and water-to-oil ratio of 4:1) and energy efficiency (76%, for reactor temperature of 250°C and water-to-oil ratio of 2:1). Based on the product quality and energy efficiency considerations, the reactor temperature of 260°C and water-to-oil ratio of 4:1 have provided the optimal condition for the lab scale continuous hydrolysis reaction. [Copyright &y& Elsevier]

Abstract: Conversion of canola oil to normal alkane hydrocarbons was investigated using sequential reactions: continuous thermal hydrolysis and fed-batch thermo-catalytic decarboxylation. The free fatty acid (FFA) intermediate product from hydrolysis was quantified using GC–FID, which showed 99.7% conversion and the following components: palmitic, oleic, linoleic, linolenic, stearic, arachidic and behenic acids. The FFA was saturated then decarboxylated at an average rate of 15.5mmoles/min using a 5% Pd/C catalyst at 300°C. Approximately 90% decarboxylation conversion to n-alkanes was achieved within 5h of the reaction. The resulting mixture of n-alkanes can be readily converted into renewable diesel using isomerization to improve the cold flow properties of the fuel. [Copyright &y& Elsevier]