Conventional Biodiesel Production Research Articles

Nanotechnology-based biodiesel: A comprehensive review on production, and utilization in diesel engine as a substitute of diesel fuel

As a sustainable replacement for fossil fuels, biodiesel is a game-changer in the energy sector. There is no strategy to minimize biodiesel's significance as a sustainable, clean fuel source in light of the increasing climate change and environmental sustainability concerns. Nevertheless, conventional biodiesel production methods often run into problems like inadequate conversion efficiency and inappropriate fuel properties, which impede their broad adoption. The revolutionary potential of nanotechnology to circumvent these limitations and revolutionize biodiesel consumption and production is explored in this review paper. There are new possibilities for improving biodiesel output and engine efficiency, thanks to nanotechnology, which can alter matter at the atomic and molecular levels. Using nano-catalysts, nano-emulsification processes, and nano-encapsulation procedures, researchers have made significant advances in improving biodiesel qualities such as stability, combustion efficiency, and viscosity. Through a comprehensive analysis of current literature and research data, this article elucidates the crucial role of nanotechnology in advancing biodiesel technology. By shedding light on the most current advancements, challenges, and potential future outcomes in nano-based biodiesel manufacturing and consumption, this review hopes to add to the growing corpus of knowledge in the field and inspire additional innovation. In conclusion, there is great hope for a sustainable energy future, increased economic growth, and reduced environmental impacts through the application of nanotechnology.  

Environmentally Safe Magnetic Nanocatalyst for the Production of Biodiesel from Pongamia pinnata Oil

Biodiesel is an alternative fuel in many developing and developed countries worldwide. Biodiesel has significant and numerous economic, environmental, and social benefits. However, the problem with conventional biodiesel production is the high industrial production cost, mainly contributed by the raw materials. Therefore, catalysts and feedstock are essential in increasing total biodiesel production rates and minimizing production costs. Magnetic nano-catalysts play a crucial role in heterogeneous catalysis due to their easy recovery, recyclability, excellent selectivity, and fast reaction rates, owing to their larger surface area. This research activity used heterogeneous magnetic nano-catalysts of ICdO, ISnO, and their modified form, to produce biodiesel. The synthesized nano-catalysts were made through co-precipitation and found quite efficient for transesterifying Pongamia pinnata oil. The effect of various parameters on biodiesel yield in the presence of prepared magnetic nano-catalysts has been studied. In the transesterification supported by ISnO, high yield, i.e., 99%, was achieved after 2 h of reaction time at 60 °C. The nano-catalysts were magnetically recovered and reused 4–5 times without any change in their activity. All the synthesized magnetic nano-catalysts performed SEM analysis. Each fraction of the produced biodiesel was assessed for different quality parameters, and the results were per ASTM standards. The components present in biodiesel produced from Pongamia pinnata oil were determined by GCMS.

Hydrogen-free deoxygenation of industrial vegetable oil waste using Ce, Zr-NiAl catalysts for second-generation biofuels production

High acidic vegetable oil feedstocks and wastes are not suitable for conventional biodiesel production. These wastes could be used to produce cheap hydrocarbon-rich biofuels without affecting food production. In this work, we studied the hydrogen-free fast pyrolysis and deoxygenation of an acidic industrial vegetable oil waste for biofuels and chemicals production, assessing the effect of Ce or Zr on NiAl mixed oxides obtained from layered double hydroxides. Oily waste (OW) was pre-adsorbed on the catalysts using a Catalyst:OW mass ratio of 5:1. Without a catalyst, pyrolysis of OW, containing triglycerides and a high percentage of free fatty acids, produced mainly 1-alkenes, lower carbon chain fatty acids, and fatty acid esters. Catalytic pyrolysis increased hydrocarbons favoring 1-alkenes between propene and 1-heptadecene, as well as alkyl-benzenes. Linear alkylbenzenes are feedstock for the production of biodegradable surfactants. NiAlCe was most selective to polyenes, alkanes and ketones, while NiAl and NiAlZr catalysts were efficient in producing aromatics, alkenes and light hydrocarbons in the GLP and gasoline range (C3-C10). The combination of acidic and metallic properties on high surface area unsupported bulk mixed oxide catalysts can be used to maximize the production of specific-range hydrocarbons for second-generation drop-in biofuels and bio-based surfactant precursors, towards the decarbonization of industry.

Optimization of Trans-esterification Processes from Three Indigenous Feedstock using Calcium Oxide-Based Catalyst

Using calcium oxide-based catalyst, optimization of two-stage trans-esterification processes at a fixed catalyst (1.0 wt. %) and molar ratio (1:6) was achieved. Processes were tested on Jatropha, Sweet Almond and Sesame seed oils to produce and compare biodiesel yields. An optimization solution of speed (629.630 rpm), temperature (26.661 oC), and time (60 min) resulted in an 83.304% for refined jatropha biodiesel (RJB) production, with an overall attractiveness of 0.853. The expected optimal yield rates of 86.915–90% obtained from various models were higher than the ASTM D 6751 and EN 14214 standards, which both required an experimental range of 46–55 % in conventional biodiesel production. The effects of speed and temperature on biodiesel yield from the refined jatropha oil (RJO), refined sweet almond oil (RSAO), and refined sesame oil (RSO) were major parameters that greatly influenced the yield, although time only changed the yield moderately.  

Biodiesel-Alkaline Transesterification Process for Methyl Ester Production

The world needs to increase renewable and alternative fuel sources such as Biomass, Bioethanol, and Biodiesel to compete with fossil fuels. Biodiesel is an important renewable fuel source since it can be used in regular diesel vehicles without requiring engine modifications. Conventional biodiesel production takes around 90 min of reaction time. A longer reaction time is not suitable for commercial production. Furthermore, traditional products such as oil react with biodiesel methoxide to produce a maximum of 90% biodiesel yield. As the catalyst is not involved with the reaction, pure methanol and methoxide (methanol with KOH catalyst) are separately added to the system to enhance the pre-reaction step. By changing the methanol to methoxide ratio, biodiesel is produced, and yield is calculated. The highest yield, which is 95%, is obtained with a 5:15% methanol to methoxide ratio. The total reaction time with the new experimental procedure is only 20 min. That is a significant reduction by saving operating costs such as energy consumption. Produced biodiesel show similar properties to that of standard biodiesel.

Transesterification of cotton oil with ethanol for biodiesel using a KF/bentonite solid catalyst

Conventional biodiesel production uses an alkaline homogeneous catalyst and alcohols of small molecules for the transesterification of vegetable and animal oils. Recent studies have shown that heterogeneous catalysts have some advantages over homogeneous catalysts for biodiesel production. Most previous studies have failed to achieve adequate conversion for these catalysts for ethyl transesterification at low temperatures and pressures. This work aims to investigate some aspects of the ethyl transesterification reaction of cottonseed oil using a Brazilian bentonite treated with potassium fluoride as a catalyst. The bentonite and the catalysts, produced using this clay, were characterized by X-ray fluorescence spectroscopy, X-ray diffraction and infrared spectroscopy. Batch transesterification experiments were performed taking into account the reaction temperature, the concentration and type of catalyst and the reaction time. The reaction conversion was estimated by gas chromatography. The characterization of the clay indicates that it is rich in montmorillonite and kaolinite, and the characterization of the catalyst indicates that the bentonite treated with potassium fluoride enhances the alkalinity and improves the transesterification reaction. The results of the transesterification tests show that at a reaction temperature of 120 °C and using 6% (w/w) of catalyst, the conversion of the cottonseed oil into esters is 95% with a catalytic activity of 4.0 g/g.h, which is high for this system. The product of the reaction has several characteristics of biodiesel, such as calorific value, density and kinematic viscosity. The stability of the catalyst can be demonstrated by the fact that the reaction conversion in the second reaction cycle was 89%, which is as high as the conversion in the first reaction cycle.

Noncatalytic Biodiesel Synthesis under Supercritical Conditions

The constant increase in greenhouse gases in the environment is forcing people to look for different ways to reduce such pollution. One of these ways is the use of biodiesel for road transport. Conventional biodiesel production involves the catalytic triglyceride transesterification process. When using homogeneous two-stage catalysis, it is difficult to purify the resulting product from the by-products formed, and the catalysts cannot be reused. In the case of heterogeneous catalysis, the process costs are increased due to separation and regeneration of the catalysts. To solve these problems of catalytic synthesis, a noncatalytic process has been recently studied that which takes place under supercritical conditions for an alcohol or other acyl receptor. In such biodiesel production, fatty feedstocks and alcohols are used as raw materials, with the synthesis taking place at supercritical conditions for alcohol, i.e., high temperature and pressure, thus making the process quite simple. This paper reviews the results obtained from biodiesel synthesis using a noncatalytic supercritical process for transesterification using both alcohols and carboxylate esters of low molecular weight, evaluating the optimal conditions for these processes and biofuel stability at high temperatures.

Production of Biodiesel from Brown Grease

Among the renewable energy sources is biodiesel. This fuel is usually produced by catalytic transesterification of vegetable oils and animal fats under heating and pressure. Brown grease is a mixture of oils, fats, solids and detergents from food industry wastes that is captured in grease traps. Brown grease is classified as waste and must be treated and disposed of appropriately. It contains oils and fats that can be converted into biodiesel. However, the high concentration of free fatty acids in brown grease does not enable the use of conventional biodiesel production schemes. This study proposes a new scheme for biodiesel production from brown grease. In addition, conditions for the effective separation of a fat phase from brown grease were tested, and the composition of a fatty phase was determined for several grease traps. Esterification and transesterification of brown grease lipids were carried out with methanol, where the Lewis acids BF3 and AlCl3 were used as catalysts and the reaction was activated by ultrasound. The results show that biodiesel can be obtained from brown grease by esterification and transesterification within several minutes under ultrasonic activation at room temperature. These results open prospects for the development of efficient, low-cost and environmentally friendly biodiesel production.

A Review on Biodiesel Synthesis using Iron Doped Catalyst

This paper summarized on the history of biodiesel synthesis, biodiesel synthesis using iron doped catalyst. Biodiesel are gaining enormous attention from researches and manufacturers considering its advantages of non-toxic, biodegradable, renewable, and environment-friendly in order to improve the air quality over the atmosphere followed by reducing the global warming problems effectively. Regarding the conventional biodiesel production method, manufacturers generally utilize vegetable oil and alcohols to pass through the transesterification process with the presence of homogeneous base catalyst. The utilization of this types of catalyst lead to another environmental issues that most of the researches are concerning about since the homogeneous catalysts are not reusable and causing separation problems between oil products and the catalyst itself. Therefore, it is highly necessary for the researches and manufacturers to further explore and investigate some catalyst types that are truly feasible for high-scale or industrial usage. Heterogeneous catalysts are known to consists of an identical phase with the reacting medium where the liquid phase contains the feedstock and reaction medium whereas the catalyst retain within the solid phase, hence resolving the separation problems that the homogeneous catalyst would lead to. Recently, researches have introduced the novel method of magnetic properties impregnation of catalytic active component onto the carbonaceous compound. This proposed action tends to provide the advantages of high surface area, separation ease, and preventing the leaching of catalytic active components from the catalyst. Both the potential iron doped carbon catalyst have been extensively researched and studied within this report. Besides, the catalyst properties have discussed further for analyzing the effects of the biodiesel yield that introduced by the chemical and physical properties of various types of catalysts.

Cost, energy and GHG emission assessment for microbial biodiesel production through valorization of municipal sludge and crude glycerol.

In this study, cost simulations were made based on 20 million L blended biodiesel B-10 production per year using INRS and conventional process. In case of INRS process, microbial lipid was produced by T. oleaginosus using washed municipal secondary sludge fortified with crude glycerol while lipid was extracted from wet biomass using biodegradable surfactant and petroleum-diesel (PD). The conventional process uses commercial substrates for lipid production and organic solvents for lipid extraction from dry biomass. The unit B-10 production cost of INRS process was estimated to be $ 0.72/L for an annual capacity of 20 million L, which is 9.5 times more economical than conventional biodiesel production process. For INRS process, the unit B-10 biodiesel production cost was sensitive to plant capacity and lipid productivity during the fermentation. INRS process exhibited positive net energy gain and positive GHG capture, which proves to be energetically and environmentally viable.

Evaluation on safety and energy requirement of biodiesel production: Conventional system and microreactors

Commercial biodiesel production through transesterification of refined bleached & deodorized palm oil (RBDPO) with methanol is commonly performed in macroscale reactors. This work focused on the comparison of biodiesel production system in terms of production efficiency and safety evaluation for both conventional and microreactor systems based on the industrial production capacity of 20,589.29L/h. Our demonstration of the laboratory biodiesel production provided high quality of biodiesel comparable to the commercial biodiesel. Design of microreactor system for scaling-out to industrial capacity was performed. The simple layout of microreactor system provided great flexibility for operation and maintenance. Less energy consumption and a small number of operators relative to the conventional biodiesel production plant are required. Safety evaluation based on HAZOP and FMEA suggested that the microreactor system was relatively safer than that of the conventional one. The risk can be further reduced by regularly maintaining and calibrating equipment according to preventive maintenance schedule.

Techno-economic assessment of conventional and direct-transesterification processes for microalgal biomass to biodiesel conversion

The simplified direct-transesterification (DT) process was compared to the conventional biodiesel production process based on a reported previous experimental work with economic standpoint. Based on the process flow diagram, capital and operating costs were itemized properly and then unit biodiesel production cost was calculated. The results show the biodiesel production costs were 18.2 $ kg−1 (conventional process) and 12.5 $ kg−1 (DT process), respectively. Sensitivity analysis shows the source of biomass and chemical consumption are the major factors to determine total biodiesel production cost. The affecting factors were a solvent recycling, yield of biodiesel, and plant capacity and these values were varied to evaluate the variation of unit biodiesel production cost. As a result, the maximized biodiesel production cost went down to 3.5 $ kg−1, which is cost-competitive with other reported values of production cost.

Biodiesel fuel synthesis by interesterification of triglycerides with carboxylate esters of low molecular weight

Abstract The ever-increasing environmental pollution from greenhouse gases motivates the search for methods to reduce it. One such method is the use of biodiesel fuels in the transport sector. Conventional biodiesel production generates up to 10% of a by-product, raw glycerol, whose amount continues to increase as biodiesel production volumes expand, but its demand remains limited. Recently, options have been analysed to replace the triglyceride transesterification process generally used in biodiesel production with an interesterification process that does not generate raw glycerol, instead yielding triacylglycerol that can be directly used as fuel for diesel engines by mixing with fatty acid esters. Additionally, triacylglycerol improves the low-temperature properties of fuel. The present article discusses triglyceride interesterification processes using various carboxylate esters of low molecular weight. Information is provided on raw materials that can be subjected to interesterification for biodiesel synthesis. The possible applications of chemical and enzymatic catalysis for triglyceride interesterification are discussed, and the influence of the catalyst amount, molar ratio of reactants, temperature and process duration on the effectiveness of interesterification is examined. The conditions and effectiveness of noncatalytic interesterification are also discussed in the article. Qualitative indicators of the products obtained and their conformity to the requirements of the European standard for biodiesel fuel are discussed.

Biodiesel production intensification through microbubble mediated esterification

Depleting fossil fuel resources and related environmental concerns have focused the world’s attention on finding sustainable and renewable energy resources such as biofuels. Biodiesel, produced from vegetable oil, animal fats, waste cooking oil, and greases, shows a promising alternative for petroleum-diesel. The conventional biodiesel production methods are time consuming and energy intensive due to mass transfer limitations. This limitation can be reduced by carrying out reaction at a bubble interface which supplies a “local” excess of alcohol to push equilibrium in the forward direction while simultaneously increasing the rate of reaction. During this process, methanol vapors, fed through a sintered borosilicate diffuser, react with the free fatty acids (oleic acid in this case) and catalyst. Owing to the lower flow rates of methanol and pore size of the diffuser (15–40 μm) used, the bubbles produced are significantly smaller 1 mm and lies in the range of 200–600 μm. Kinetic study shows that reaction follows first order kinetics w.r.t. oleic acid. The esterification reaction through bubble reactor achieved 97% conversion of oleic acid in 30 min as compared with 80% in 312 min using conventional methods.

Valorisation of Edible Oil Wastewater Sludge: Bioethanol and Biodiesel Production

This study aimed to reuse primary wastewater sludge from the edible oil industry as a novel feedstock for both monounsaturated fats and bioethanol for biodiesel production. Results showed that the fatty acid profile of the oilseed primary wastewater sludge was favourable for biodiesel production; with a maximum 45% (w/w) monounsaturated fats extracted using ethanol at an ethanol to solid ratio of 25:1. The residue after the extraction of fats from the sludge contained sufficient fermentable sugars for bioethanol production. A maximum theoretical yield of bioethanol of 106% was obtained after enzymatic hydrolysis followed by fermentation using the industrial Saccharomyces cerevisiae strain MH-1000 at an optimum density of 2 × 105 CFU/mL. A novel nano-magnetic catalyst synthesised from cupriferous mineral processing wastes was employed. A maximum biodiesel yield of 94% was obtained at an oil to ethanol ratio of 1:9, catalyst loading of 5 wt.%, and reaction time of 180 min at 75 °C. The approach employed in this study has the potential to reduce material costs, energy consumption and water usage associated with conventional biodiesel production technologies. It may also mitigate the impacts of conventional biodiesel production on food and land security, while simultaneously reducing waste.

Experimental Determination of Optimal Conditions for Reactive Coupling of Biodiesel Production With in situ Glycerol Carbonate Formation in a Triglyceride Transesterification Process.

This study investigated a reactive coupling to determine the optimal conditions for transesterification of rapeseed oil (RSO) to fatty acid methyl ester (FAME) and glycerol carbonate (GLC) in a one-step process, and at operating conditions which are compatible with current biodiesel industry. The reactive coupling process was studied by transesterification of RSO with various molar ratios of both methanol and dimethyl carbonate (DMC), using triazabicyclodecene (TBD) guanidine catalyst and reaction temperatures of 50–80°C. The optimal reaction conditions obtained, using a Design of Experiments approach, were a 2:1 methanol-to-RSO molar ratio and 3:1 DMC-to-RSO molar ratio at 60°C. The FAME and GLC conversions at the optimal conditions were 98.0 ± 1.5 and 90.1 ± 2.2%, respectively, after 1 h reaction time using the TBD guanidine catalyst. Increase in the DMC-to-RSO molar ratio from 3:1 to 6:1 slightly improved the GLC conversion to 94.1 ± 2.8% after 2 h, but this did not enhance the FAME conversion. Methanol substantially improved both FAME and GLC conversions at 1:1–2:1 methanol-to-RSO molar ratios and enhanced the GLC separation from the reaction mixture. It was observed that higher methanol molar ratios (>3:1) enhanced only FAME yields and resulted in lower GLC conversions due to reaction equilibrium limitations. At a 6:1 methanol-to-RSO molar ratio, 98.4% FAME and 73.3% GLC yields were obtained at 3:1 DMC-to-RSO molar ratio and 60°C. This study demonstrates that formation of low value crude glycerol can be reduced by over 90% compared to conventional biodiesel production, with significant conversion to GLC, a far more valuable product.

Evaluation of Lipases from Wild Microbial Strains as Biocatalysts in Biodiesel Production

In this study, the evaluation of the catalytic behavior of several wild bacterial strains in the 1,3-selective ethanolysis of triglycerides with ethanol to produce a new type of biodiesel (Ecodiesel) that integrates glycerol as monoacylglycerols was carried out. The Ecodiesel production not only avoids the elimination of glycerol, which is largely generated as a by-product in the biodiesel industry, but also results in an increase in the biofuel yield. The wild microbial strain samples were obtained from several lipophilic organisms. In addition to evaluate the enzymatic extracts, the minimum grade of purification of the strains, necessary to obtain similar results to those attained with commercial lipases was studied. This purification treatment included a dialysis followed by a lyophilization process. Such extracts were directly used as biocatalysts in the transesterification reaction of sunflower oil with ethanol, attaining much better results (yield close to 100%) than those obtained with strains which were not submitted to the purification process (yields lower than 10%). Furthermore, the results here obtained are similar to those obtained with commercial lipases but were achieved under mild conditions and lower reaction time (2 h). In addition, the stability of the enzymatic extracts was corroborated by subsequent reactions, showing no loss of activity. Thus, this study brings to light that enzymatic extracts obtained by a very simple purification process can be economically competitive with the conventional biodiesel production methods.

Simultaneous development of biodiesel synthesis and fuel quality via continuous supercritical process with reactive co-solvent

This work addresses the simple and effective technique to simultaneously improve biodiesel synthesis and fuel quality. The co-solvent technology was applied to fulfill this purpose. Experiments were performed through the transesterification of palm oil and ethanol in a microtube reactor under the supercritical conditions. The iso-propanol was added in the system and played the roles as a source of reactant to produce isopropyl esters and co-solvent to enhance the homogeneity of the mixture. Upon the application of iso-propanol, high yield of biodiesel was attained under the milder conditions than those reported in the literature in terms of reaction temperature, pressure, residence time, and ethanol-to-oil molar ratio. The influence of operating conditions on the %Ester was investigated and optimization of %Ester was carried out via response surface methodology. The improvement of biodiesel quality was achieved particularly the cloud and pour points which were better quality than that of the conventional biodiesel production.

Effect of Quaternary Ammonium Salt Addition to Conventional Biodiesel Production Process

Biodiesel on a commercial scale is largely produced by transesterification using a conventional homogeneous catalyst like KOH and NaOH. The major problem associated with conventional homogeneous transesterification process is that it is prone to water & FFA content. This problem can be mitigated with some process modification using quaternary ammonium salts. In the present study, the reaction between waste palm oil & methanol was carried in a batch reactor at 65oC & various molar ratios of oil to methanol. Further, the effect of various dosages of tetramethylammonium bromide (TMAB) addition to this reaction was studied. Results show that there is a strong influence of TMAB (a phase transfer catalyst) on the methanol requirement during the reaction and also on the washability characteristics of the produced biodiesel. It was observed that there is a considerable decrease in the molar ratio of methanol to oil requirement during the reaction. Moreover, the addition of TMAB has enhanced the washability of the final biodiesel product by forming less foam. This has a direct advantage of decreasing the water requirement during the purification process. 

The effect of hydrodynamic and ultrasonic cavitation on biodiesel production: An exergy analysis approach

Today, the increase in the production and consumption of biofuels such as biodiesel in the transportation sector is considered an appropriate solution to decrease the consumption of fossil fuels and their consequent pollutions. However, in order to increase energy efficiency and minimize energy losses and waste materials, the biodiesel production processes require the particular revisions and modifications. In the present study, the exergy analyses of the mechanical stirrer (MS), ultrasonic cavitation (UC) and hydrodynamic cavitation (HC)-based biodiesel production processes were performed and the results were compared together, in order to improve the efficiency of the biodiesel production process. To compare the results, three parameters of the exergy waste emission, the exergy destruction, and the exergy efficiency were used. The results indicated that both the cavitation processes lead to improved exergy efficiency in the biodiesel production. However, the HC process proved to be a more appropriate option to replace the conventional biodiesel production process equipped with stirred-rank reactors (the MS process) due to eliminating the main waste streams, decreasing exergy destruction to half, and increasing exergy efficiency by 6.2%.