Low-Cost Feedstock Conversion to Biodiesel via Ultrasound Technology

Enhancement of Biodiesel Production via Ultrasound Technology: A Mathematical Study

Biodiesel is one of the alternative renewable energy sources that has received a lot of attention since it is clean, green energy. Different sources can be used for the production of biodiesel, but the most appropriate and economical method relies on the transesterification of methanol with the nonedible vegetable oil from the fruit of the Jatropha curcas plant. Molar ratio, vessel diameter, catalyst concentration, and ultrasound all have a substantial influence on the synthesis of biodiesel by the transesterification process. Among these factors, the diameter of the vessel and the ultrasonic effect through mass transfer limitations have a significant impact on successful reaction completion. In this research work, we have developed a mathematical model to analyze the three-step transesterification process and side saponification reaction in the presence of a potassium hydroxide catalyst. The model considers the influence of mixing intensity variations, including ultrasound, on the mass transfer in different phases. The mass transfer rate is calculated using the modified Dittus-Boelter correlation. An optimal control approach through the minimum principle by Pontryagin is applied to maximize the production of biodiesel at minimal cost. The novelty of this research, which we have derived from our analytical as well as numerical results, considering industrial processes, is that more than 97% biodiesel yield conversion is to be obtained at 50 kHz ultrasound frequency, a 6:1 methanol-to-Jatropha-oil molar ratio, and 1 m of vessel diameter within 50 min using optimal control theory.

Ultrasound-assisted transesterification of soybean oil using low power and high frequency and no external heating source

In this work, high frequency and low power ultrasound without external heating source and mechanical stirring in biodiesel production were studied. Transesterification of soybean oil with methanol and catalyzed by KOH was investigated using ultrasound equipment and ultrasonic transducer. The effect of ultrasonic output power (3 W-9 W), ultrasonic frequency (1 MHz and 3 MHz), and alcohol to oil molar ratio (6:1 and 8:1) have been investigated. The increase in ultrasonic power provided higher conversion rates. In addition, higher conversion rates were obtained by increasing the ultrasonic frequency from 1 MHz to 3 MHz (48.7% to 79.5%) for the same reaction time. Results also indicate that the speed of sound can be used to evaluate the produced biodiesel qualitatively. Further, the ultrasound system presented electric consumption (46.2W∙h) four times lower than achieved using the conventional method (211.7W∙h and 212.3W∙h). Thus, biodiesel production using low power ultrasound in the MHz frequency range is a promising technology that could contribute to biodiesel production processes.

Potential of Jatropha curcas L. as Biodiesel Feedstock in Malaysia: A Concise Review

Fluctuation in fossil fuel prices and the increasing awareness of environmental degradation have prompted the search for alternatives from renewable energy sources. Biodiesel is the most efficient alternative to fossil fuel substitution because it can be properly modified for current diesel engines. It is a vegetable oil-based fuel with similar properties to petroleum diesel. Generally, biodiesel is a non-toxic, biodegradable, and highly efficient alternative for fossil fuel substitution. In Malaysia, oil palm is considered as the most valuable commodity crop and gives a high economic return to the country. However, the ethical challenge of food or fuel makes palm oil not an ideal feedstock for biodiesel production. Therefore, attention is shifted to non-edible feedstock like Jatropha curcas Linnaeus (Jatropha curcas L.). It is an inedible oil-bearing crop that can be processed into biodiesel. It has a high-seed yield that could be continually produced for up to 50 years. Furthermore, its utilization will have zero impact on food sources since the oil is poisonous for human and animal consumption. However, Jatropha biodiesel is still in its preliminary phase compared to palm oil-based biodiesel in Malaysia due to a lack of research and development. Therefore, this paper emphasizes the potential of Jatropha curcas as an eco-friendly biodiesel feedstock to promote socio-economic development and meet significantly growing energy demands even though the challenges for its implementation as a national biodiesel program might be longer.

Optimization of an Ultrasonic-Assisted Biodiesel Production Process from One Genotype of Rapeseed (TERI (OE) R-983) as a Novel Feedstock Using Response Surface Methodology

In recent years, due to the favorable climate conditions of Iran, the cultivation of rapeseed has increased significantly. The aim of this study was to investigate the possibility of biodiesel production from one genotype of rapeseed (TERI (OE) R-983). An ultrasonic approach was used in order to intensify the reaction. Response surface methodology (RSM) was applied to identify the optimum conditions of the process. The results of this research showed that the conversion of biodiesel was found to be 87.175% under the optimized conditions of a 4.63:1 molar ratio (methanol to oil), 56.50% amplitude, and 0.4 s pulses for a reaction time of 5.22 min. Increasing the operating conditions, such as the molar ratio from 4:1 to 5.5:1, amplitude from 50% to 72.5%, reaction time from 3 min to 7 min, and pulse from 0.4 s to 1 s, increased the FAME (fatty acid methyl esters) yield by approximately 4.5%, 2.3%, 1.2%, and 0.5%, respectively. The properties of the TERI (OE) R-983 methyl ester met the requirements of the biodiesel standard (ASTM D6751), indicating the potential of the produced biodiesel as an alternative fuel.

Ultrasound assisted synthesis of biodiesel from karanja oil by interesterification: Intensification studies and optimization using RSM

The present work deals with the optimization of interesterification of karanja oil using response surface methodology (RSM) analysis with intensification studies based on the use of ultrasound. Esterification of karanja oil was performed as a pretreatment under fixed optimum conditions of molar ratio of 1:10, catalyst loading of 3.5% and temperature of 60 °C to reduce the acid value from initial of 10.5 mg of KOH/g to 1.8 mg of KOH/g. The pretreated oil was used for interesterification where the process parameters considered for optimization were time (X1), catalyst loading (X2), reactant ratio (X3) and duty cycle (X4), each varied at three levels. The maximum yield of FAME achieved using optimum parameters as time of 35 min, catalyst loading of 1 wt%, reactant ratio of 1:9 (mol:mol) and duty cycle of 60% was 91.56% (on the basis of theoretical ester formation). The effect of reaction temperature was also studied keeping other parameters constant at optimum conditions and it was observed that yield increases continuously with an increase in the temperature over the entire range of temperature. It was also demonstrated that ultrasound assisted interesterification approach gives less requirement of methyl acetate and catalyst as compared to the conventional approach. It was also observed that higher yield was obtained in the presence of ultrasound (91%) as compared to the conventional approach (60%). Kinetic studies established that second order rate equation fits the obtained data well. A mathematical model in RSM was also successfully developed which can be used to make predictions about the expected conversion. Overall the work demonstrated the intensification benefits of using ultrasound and established the optimum conditions for maximum benefits using RSM analysis.

Comparison between Conventional and Ultrasonic Preparation of Chitosan from Shrimp Shells Waste

Chitosan is a natural biopolymer derived by deacetylation of chitin from the two main sources of crustaceans, shrimp and crabs. Chitosan, which is soluble in acidic solutions, is used in many applications (biomedical/pharmaceutical, water engineering, food, cosmetics). There have been many researchers who have developed a process of deacetylation of chitin from shrimp shells waste by thermochemical or enzymatic methods. However, application of ultrasonic irradiation for chitin deacetylation has received little attention. In this work, the deacetylation of chitin with concentrated sodium hydroxide was performed using ultrasound irradiation (80 W, 42 kHz). The reaction time and degree of deacetylation were compared with conventional process. Results showed that under the same condition, the degree of deacetylation was similar. However, the use of ultrasonic irradiation decreased the reaction time, showing that this method may be a promising alternative method to the conventional method.

Biodiesel synthesis and conformation of lipase from Burkholderia cepacia in room temperature ionic liquids and organic solvents

Biodiesel synthesis and conformation of Burkholderia cepacia lipase (BCL) were studied in 19 different room temperature ionic liquids (RTLLs) with a range of cation and anion structures. Overall, anion selection had a greater influence on biodiesel conversion than cation choice. RTILs containing Tf2N- and PF6- anions were suitable reaction media, while RTIL of [OmPy][BF4] was the best reaction medium with a biodiesel yield of 82.2±1.2%. RTILs with strong water miscible properties showed very low biodiesel yields. Conformational analysis by FT-IR revealed that higher biodiesel conversion in RTILs was correlated with a low tendency in α-helix content of BCL. An ultrasound-assisted biocatalysis process in RTILs was used to improve mass transfer rate, leading to 83% reduction of the reaction time for biodiesel production.