Modeling of process intensification of biodiesel production from Aegle Marmelos Correa seed oil using microreactor assisted with ultrasonic mixing

A review on biodiesel micromixers: Types of micromixers, configurations, and flow patterns

The production of biodiesel conventionally relies on batch reactors for the transesterification of oil and alcohol. However, the inherent limitations of batch-wise biodiesel production, including biphasic oil and alcohol, the establishment of equilibrium during transesterification, and heightened manufacturing costs, underscore the need for intensifying biodiesel synthesis. The integration of microreactors and micromixers presents a promising avenue to achieve these objectives, driving significant interest in the development of continuous biodiesel synthesis within microreactor systems. Continuous microreactors, empowered by micromixers, offer key advantages such as a heightened interfacial area between immiscible reactants and phases, as well as reduced mass transfer resistance, culminating in elevated biodiesel yields. Consequently, the micromixer emerges as a pivotal component in microreactor systems. This review delves into the pivotal role of micromixers in biodiesel production within microreactors, shedding light on micromixer types, channel configurations, reactor dimensions, mixing indices, and the influence of co-solvents in micromixers. The efficiency of various micromixer types is meticulously analyzed using a mixing index and yield of oil. Furthermore, the review addresses the challenges inherent in biodiesel production when employing micromixers and microreactors.

A review on machine learning approaches for microalgae cultivation systems

Microalgae plays a crucial role in biomass production within aquatic environments and are increasingly recognized for their potential in generating biofuels, biomaterials, bioactive compounds, and bio-based chemicals. This growing significance is driven by the need to address imminent global challenges such as food and fuel shortages. Enhancing the value chain of bio-based products necessitates the implementation of an advanced screening and monitoring system. This system is crucial for tailoring and optimizing the cultivation conditions, ensuring the lucrative and efficient production of the final desired product. This, in turn, underscores the necessity for robust predictive models to accurately emulate algae growth in different conditions during the initial cultivation phase and simulate their subsequent processing in the downstream stage. In pursuit of these objectives, diverse mechanistic and machine learning-based methods have been independently employed to model and optimize microalgae processes. This review article thoroughly examines the techniques delineated in the literature for modeling, predicting, and monitoring microalgal biomass across various applications such as bioenergy, pharmaceuticals, and the food industry. While highlighting the merits and limitations of each method, we delve into the realm of newly emerging hybrid approaches and conduct an exhaustive survey of this evolving methodology. The challenges currently impeding the practical implementation of hybrid techniques are explored, and drawing inspiration from successful applications in other machine-learning-assisted fields, we review various plausible solutions to overcome these obstacles.

Synthesis, catalysts and enhancement technologies of biodiesel from oil feedstock - A review

Biodiesel is considered as one of the most promising alternative fuels due to the depletion of fossil fuels and the need to cope with potential energy shortages in the future. This article provides a thorough analysis of biodiesel synthesis, covering a variety of topics including oil feedstock, synthesis methods, catalysts, and enhancement technologies. Different oil feedstock for the synthesis of biodiesel is compared in the review, including edible plant oil, non-edible plant oil, waste cooking oil, animal fat, microbial oil, and algae oil. In addition, different methods for the synthesis of biodiesel are discussed, including direct use, blending, thermal cracking, microemulsions, and transesterification processes, highlighting their respective advantages and disadvantages. Among them, the transesterification method is the most commonly used and a thorough examination is given of the benefits and drawbacks of utilizing enzymatic, heterogeneous, and homogeneous catalysts in this process. Moreover, this article provides an overview of emerging intensification technologies, such as ultrasonic and microwave-assisted, electrolysis, reactive distillation, and microreactors. The benefits and limitations of these emerging technologies are also reviewed. The contribution of this article is offering a thorough and detailed review of biodiesel production technologies, focusing mainly on recent advances in enhanced chemical reaction processes. This provides a resource for researchers to assess and compare the latest advancements in their investigations. It also opens up the potential for enhancing the value of oil feedstocks efficiently, contributing to the development of new energy sources.

Treatment of Saussurea heteromalla for biofuel synthesis using catalytic membrane reactor

Membrane technology has been adopted as a prospective and promising alternative to the standard technology used for biodiesel production since the time when it had some limitations. During this research project, the inedible seed oil generating feedstock known as Saussurea heteromalla was put through a biodiesel production process that utilized membrane technology with an effort to increase the yield of methyl ester. The transesterification process was mediated by zirconium oxide nanoparticles that were generated using an aqueous extract of Portulaca oleracea leaf. With an oil to methanol ratio of 1:9, a catalyst concentration of 0.88 (wt. %), temperature of 87 °C, and reaction time of 180 min, the highest possible biodiesel yield of 93% was achieved. The findings of the catalyst characterization demonstrated the purity of the zirconium oxide nano particles and their nanoscale nature with average particle size of 31 nm. Using gas chromatography and mass spectrometry (GC/MS), an examination of biodiesel revealed the presence of four different peaks of methyl esters. Using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance, we were able to verify that the production of methyl esters in the biodiesel sample was successful (NMR). Zerconium oxide nanoparticles were found reusable up to five consecutive cycles of transesterification. The fuel-related properties of methyl ester have been determined and are in line with the requirements of the international standards ASTM D-6571 and EN 14214. In the course of our ongoing research, we made use of membrane technology, which led to the production of biodiesel from the seed oil of Saussurea heteromalla that was better for the environment, more cost effective, and produced in greater quantities.

Continuous Double-Step Esterification Production of Palm Fatty Acid Distillate Methyl Ester Using Ultrasonic Tubular Reactor

Double-step esterification to produce biodiesel from palm fatty acid distillate (PFAD) was performed by utilizing an ultrasound clamp reactor. Six pairs of ultrasonic clamps were attached to the left and right sides of the stainless-steel tube, and each pair was separated 100 mm apart from each other. Therefore, a total of 12 units of ultrasound clamps distributed 4800 W maximum power (12 × 400 W) throughout the continuous reactor by an ultrasonic generator. To optimize each step of the continuous esterification process for producing methyl ester from PFAD, a response surface methodology was used. The final 93.32 wt % methyl ester purity was attained under a double-step esterification process. For the first step, a 3.75:1 molar ratio of methanol to PFAD (46.4 vol % methanol), 6.6 vol % sulfuric acid, and 400 mm length of ultrasound clamp at 25 L/h PFAD flow rate for converting the PFAD to 60.24 wt % methyl ester were recommended. For the second step, the esterification was repeated under a molar ratio of methanol to the first esterified oil of 2.87:1 (61.6 vol % methanol), 5.6 vol % of sulfuric acid, and 400 mm length of ultrasound clamp at 25 L/h esterified oil flow rate. The ultrasonic clamp reactor achieved high yields of esterified oil and the crude biodiesel in a relatively short residence period of 32 s. To determine the product yields of a double-step esterification process, the maximum yields were 103.9 wt % first esterified oil, 107.6% crude biodiesel, and 98 wt % purified biodiesel when calculated on the basis of 100 vol % initial PFAD. The average energy consumed in the production of double-step esterification biodiesel was 0.05796 kWh/L. Therefore, this current approach has a high potential for producing biodiesel with less energy and requires less time to convert the PFAD to a high purity of methyl ester.

Enhancement of lipid accumulation in microalga Desmodesmus sp. VV2: Response Surface Methodology and Artificial Neural Network modeling for biodiesel production

Microalgae are the most attractive renewable energy sources for the production of biofuels because of their luxurious growth and lipid accumulation ability in diverse nutritional conditions. In the present study, Desmodesmus sp. VV2, an indigenous microalga, was evaluated for its biodiesel potential using Response Surface Methodology (RSM) to improve the lipid accumulation with the combination of nutrients stress NaNO₃ starvation, CaCl₂ depletion, and supplementation of magnesium oxide nanoparticles (MgO). Among different stress conditions, 57.6% lipid content was achieved from RSM optimized media. Owing to this, RSM results were also validated by the Artificial Neural Network (ANN) with 11 training algorithms and it is found that RSM was more significant. In addition, the saturated fatty acid (SFA) content was noticeably increased in RSM optimized media (95.8%) while compared with control. Further, the highest total FAME content 97.21% was also achieved in cells grown in RSM optimized media. Biodiesel quality parameters were analyzed and found that they are in accordance with international standards. Thus, this study suggesting that the fatty acid profile of Desmodesmus sp. VV2 attained under optimized media conditions would be suitable for biodiesel production for future energy demand.

Investigation on the effect of ultrasound irradiation on biodiesel properties and transesterification parameters

This work examines the effect of ultrasound irradiation (UI) on biodiesel properties and transesterification parameters. Methanol content, reaction time, reaction temperature, and catalyst concentration are varied, and the optimum condition for maximum possible yield was held constant for both processes. Biodiesel obtained from non-edible oils is the most promising alternative fuel for conventional diesel fuel. In this study, sterculia foetida seed oil was used for biodiesel production. Sterculia foetida oil was transesterified to lower its FFA using UI and compared with the conventional process. Both heating processes were optimized to yield a maximum of 94.3% at a six molar ratio, 50 °C, (water temp), 1% wt of catalyst (KOH), and 75 min reaction time. Transesterification by UI reduced the total reaction time to 4 min compared to 75 min at the conventional process. Further UI influenced the properties of biodiesel (SOBD) from SO. UI lowered viscosity by 7.3% and density by 5.5% and facilitated using oxygen content of SOBD.

Sol-Gel Entrapped Lewis Acids as Catalysts for Biodiesel Production

Replacing fossil fuels with biodiesel enables the emission of greenhouse gases to be decreased and reduces dependence on fossil fuels in countries with poor natural resources. Biodiesel can be produced by an esterification reaction between free fatty acids (FFAs) and methanol or by transesterification of triglycerides from oils. Both reactions require homogeneous or heterogeneous catalysis. Production of biodiesel catalyzed by heterogeneous catalysts seems to be the preferred route, enabling easy product separation. As we have previously shown, the Lewis acids AlCl3 and BF3 can serve as highly efficient catalysts under ultrasonic activation. The present study focused on the development of oleic acid (OA) esterification with methanol by the same catalysts immobilized in silica matrices using the sol-gel synthesis route. During the course of immobilization, AlCl3 converts to AlCl3 × 6H2O (aluminite) and BF3 is hydrolyzed with the production of B2O3. The immobilized catalysts can be reused or involved in a continuous process. The possibility of biodiesel production using immobilized catalysts under ultrasonic activation is shown for the conversion of FFAs into biodiesel in batch and continuous mode.