Continuous Biodiesel Production Research Articles

Application of rotating cone reactor for continuous biodiesel production: Effect of cone geometry and optimization of operating variables through response surface methodology (RSM)

The work developed a rotating cone reactor (RCR) as a promising multifunctional reactor for continuous biodiesel production from refined palm oil (RPO) homogeneously catalysed by NaOH. The effects of rotating cone geometry, rotational speed, catalyst amount, and reactant feed flow rate on FAME yield were investigated. Response surface methodology (RSM) and the Design Expert software were used to optimize the operating variables. The grooved cone surface was found to play an important role in increasing FAME yield. The model predicted a maximum FAME yield of 96.9 % at the process conditions of NaOH loading of 0.602 wt.% of oil, a feed flow rate of 298 mL/min, and a rotational speed of 751 rpm. It provided a high yield efficiency of 1.324 × 10−3 g/J and a high productivity of 0.715 mol/min at a very short residence time of 2 – 3 s. This resulted in a significant reduction in transesterification time, suggesting that the RCR is a promising multifunctional reactor for economical continuous biodiesel production.

Hierarchical MPC‐based control structure for continuous biodiesel production

AbstractThis paper presents an advanced control strategy for a continuous biodiesel production plant based on a steady‐state optimizer and model predictive control (MPC). The proposed control system aims to optimize the production process and maintain product quality within required specifications. First, two steady‐state optimizers were developed with the aim of minimizing the steady‐state deviations of the manipulated and controlled variables and minimizing the biodiesel production cost. An MPC was then formulated to track the set points imposed by the steady‐state optimizers in real time and manipulate the control inputs accordingly. The scope of this work is limited to measured disturbances only. The effectiveness of the proposed control strategy is demonstrated through dynamic simulation studies performed using HYSYS and MATLAB. The results obtained using the proposed control methodology show significant improvements in performance compared to conventional control strategies. Furthermore, it avoids the quality problem reflected in the amount of water in the final product that the original plant presented due to an inadequate design of the control strategy. Overall, the results of this research indicate that the proposed advanced control strategy has the potential to improve the efficiency and profitability of continuous biodiesel production plants.

Design and construction of a single orifice oscillatory flow reactor for the continuous production of biodiesel from sunflower oil

Biodiesel, a renewable energy replacing fossil fuels, exhibits eco-friendly traits with beneficial lubrication properties. This research aims to design and construct a single-orifice oscillatory flow reactor to reduce the reaction time, improve the mixing process, and increase efficiency. The response surface method was used for the analysis of independent parameters like molar ratio (1:6–1:12), temperature (30–50 °C), reactor length (1–3 m), and catalyst concentration (0.75%-1.25%) on yield as the dependent variable. Elevated temperature up to 50 °C enhances conversion from 61.91% to 69.51%, peaking at 65.43% by 60 °C, adjusting the molar ratio to 1:9 boosts biodiesel conversion from 58.70% to 69.51%, dropping by 4% at 1:12 ratio. Catalyst concentration at 1% heightens conversion from 48.82% to 69.51%, but at 1.25%, it falls to 57.26%. Increasing reactor length to 2 m yields a 20% boost, while at 3 m, conversion drops by 4%. Optimal conditions, at 40 °C, 1:9 ratio, 1% catalyst, and 3 m reactor, resulted in a 91.98% conversion percentage. Experimental verification at the suggested point yields an 89% conversion, aligning acceptably with the model’s prediction. Biodiesel meets EN 14214 standards, positioning it as a viable diesel fuel alternative.

Optimization of methyl ester synthesis using gas/liquid phase pulsed discharge plasma in a novel oscillatory slug flow reactor

In the present research, an innovative oscillatory slug flow reactor (OSFR) under the treatment of gas–liquid phase pulsed discharge plasma was developed for biodiesel production. The main goal was continuous production of high quality biodiesel at low temperature and pressure. Experimental tests were carried out under the influence of four main operating parameters including applied voltage, molar ratio, reactant flow rate, and catalyst concentration. The response surface method was employed to optimize experimental tests. The results showed that the proposed technology provided 94% production efficiency under the optimal conditions of voltage 19.4 kV, molar ratio 6.4, flow rate 2.7 ml/s, and catalyst 0.9 wt. %. According to the statistical analysis, increasing the applied voltage and reducing the flow rate have a strong effect on the Fatty Acid Methyl Ester yield, while the concentration of potassium hydroxide and methanol have less effect on the overall efficiency. In addition, the characteristics of the produced biodiesel were in accordance with ASTM D6751 standards. Surprisingly, the optimal energy consumption in this system was 95 kJ/l, which is more economically viable. In general, this study showed that the combined system of gas/liquid phase plasma in the OSFR reactor has a high synergistic potential for the transesterification reaction.

Smart scale-up of micromixers for efficient continuous biodiesel synthesis: A numerical study for process intensification

This study focuses on developing continuous processes for biodiesel synthesis, overcoming limitations of conventional batch reactions, such as biphasic reaction and thermodynamic equilibrium, and reducing production costs. While microreactors are promising for enhancing mixing and transfer rates at smaller scales, scaling up to larger channels results in decreased efficiency and product yield. Microfluidic devices, useful in continuous biodiesel production, lose mixing efficiency when scaled up, affecting product yield. The present study proposes a novel microreactor design with static elements, aiming to improve fluid mixing and reaction performance at higher volumes. The smart scale-up strategy includes an optimized micromixer design, enlarged channel cross-sectional area, and an additional obstacle-free channel. Using a Fractional Design followed by a Central Compound Rotational Design, optimal values for key design variables are identified. Computational tests show a high mixing index (M > 0.77) across a wide range of Reynolds numbers (Re = 0.1–100). Numerical simulations under optimal conditions indicate high conversions (>91 %) for residence times above 60 s. This design promises advancements in industrial-scale biodiesel production, with improved flow and reactant distribution, potentially reducing the number of micro/millidevices needed.

Biodiesel Production from Jatropha Curcas Oil Using Li/Pumice as Catalyst in a Fixed-Bed Reactor

A packed-bed catalytic configuration reactor using pumice granules loaded with lithium (Li/Pumice) as a heterogeneous catalyst was developed for the continuous biodiesel production. For this purpose, Jatropha curcas oil was used as an alternative feedstock to edible oils and diethyl ether was used as a cosolvent to improve the mass transfer between the phases present in the transesterification reaction. The solid catalyst was characterized, and its catalytic activity was evaluated for the biodiesel production. Fatty acid methyl esters (FAME) yield of 100% was achieved under the conditions of 1.4 mL min-1, 20.0 methanol/oil molar ratio, 0.57:1 cosolvent/methanol molar ratio and 40ºC. Moreover, Li/Pumice catalyst shows high stability for the continuous biodiesel production.

Unleashing the Power of Plasma and Flow: A Novel Cold Plasma‐Oscillatory System for Enhanced Continuous Biodiesel Production from Sunflower Oil

While fossil fuel resources are limited, the increasing demand for energy in the industrial and transportation sectors has led to using renewable fuels. This study aims to improve biodiesel production from sunflower oil by combining cold plasma and oscillatory systems through a transesterification process. The four main operational variables are examined, such as molar ratio (MR) (1:6–1:12), catalyst concentration (CC) (0.5–1.25 wt%), plasma exposure time (PET) (25–75 s), and residence time (RT) (30–90 s). The smooth periodic constriction reactor's physical attributes, including the diameter of the tube (D), the diameter of the constricted region (d0), and the distance between baffles (l), as well as the properties of the cold plasma system, are determined. The data analysis presents that PET, RT, CC, and MR have the greatest effect on efficiency. This optimization indicates that by exposing the reaction mixture to plasma for 59.99 s, adding 1.09% by weight of the catalyst, and with a MR of 7.17 in 86.43 s, biodiesel with a conversion percentage of 94.75% is produced. The results show that the optimum point matches with EN 14214 standard.

Continuous reciprocating plate and packed bed multiphase reactors in biodiesel production: Advancements and challenges

Biodiesel, a renewable and environmentally friendly alternative to conventional fossil fuels, has gained significant attention over the last two decades. Continuous production of biodiesel offers efficiency, productivity, and scalability advantages. This paper provides a concise overview of continuous reactor systems for biodiesel production, focusing on two specific systems-the reciprocating plate reactor and the packed bed reactor-subjects of the authors' extensive research. A thorough comparison of these reactors, spanning biodiesel yield, reaction kinetics, and conversion efficiency, underscores their advantages. The reciprocating plate reactor demonstrates superior mixing characteristics, which improve mass transfer and reaction kinetics. Conversely, the packed bed reactor offers a higher catalyst-to-feedstock ratio and longer residence time, enhancing conversion efficiency. Both reactors exhibit favourable performance for continuous biodiesel production. This research can contribute to understanding continuous biodiesel production using innovative reactor designs. The comparative analysis between the reciprocating plate and packed bed reactors offers valuable insights for process optimization and reactor selection based on specific requirements such as feedstock availability, reaction kinetics, and economic considerations. These insights pave the way for the implementation of sustainable and efficient biodiesel production processes in the future.

Novel Corncob‐Based Catalytic Biodiesel Production Process: Experiments, Modeling, and Simulation

AbstractA functionalized catalyst for catalyzed biodiesel production via a heterogeneous route is a highly focused area to lower the cost of production and mitigate the drawbacks of homogeneously catalyzed reactions. Production aspects such as parameter study, kinetics modeling, and simulation of continuous process flowsheets incorporating kinetic parameters are scarce in the literature. In the current work, a sulfonic group‐functionalized porous carbonaceous catalyst based on corncob was used for the esterification of oleic acid. The Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) kinetic model was found to best fit to correlate the experimental data and thus applied to deduce the kinetic parameters. The obtained kinetic parameters were incorporated into the Aspen Plus simulator to simulate the continuous biodiesel production process. The catalyst showed a strong affinity for oleic acid which enhances the reaction rate.

Toward Efficient Continuous Production of Biodiesel from Brown Grease

An increase in energy consumption and the extended use of nonrenewable fossil fuels raises the need to develop alternative fuels as an energy supply that can protect the environment from unwanted emissions of pollutants. One alternative renewable fuel is biodiesel. Currently, most biodiesel feed sources are edible oils, but using them leads to the dilution of global food sources. The present study aims to find an effective method of biodiesel production using food industry fatty wastes called brown grease (BG). BG contains fats, mainly linoleic and oleic free fatty acids (FFAs), that can serve as raw materials for biodiesel production using esterification reactions. The esterification and transesterification reactions for biodiesel production were studied using commercial FFAs, commercial glyceryl trilinoleate (trilinolein), soybean oil, and BG. The reactions were carried out under ultrasonic activation using BF3 and AlCl3 Lewis acids as catalysts in both free and immobilized forms when immobilization was performed in silica matrices using the sol-gel synthesis route. Biodiesel production was examined in batch and continuous flow reactors. The BF3 catalyst was more efficient at the initial stages of the continuous operation, reaching a maximum conversion of 90%, with a gradual decrease in efficiency after 15 h of the process. The AlCl3 catalyst showed better stability, reaching maximum yields of 97% and maintaining efficiency until the end of the experiment. The proposed method offers an efficient and easy way to produce biodiesel from a variety of lipids sources, including fatty wastes (BG).

Optimization of a novel liquid phase capillary discharge plasma reactor for continuous methyl ester synthesis

Conventional transesterification processes not only require large amounts of methanol and catalysts but are also time-consuming and operate at high temperatures. Advanced methods such as non-thermal plasma have been studied for biodiesel production because they mainly reduce the temperature as well as the reaction time. In this study, a liquid-phase capillary discharge plasma reactor was developed for the continuous production of biodiesel from sunflower oil at ambient temperature and pressure. The four main operational parameters were examined each with three levels, including molar ratio (4, 6, 8), catalyst concentration (0.5, 1, 1.5 wt%), applied voltage (10, 15, 20 kV), and reactant flowrate (2, 4, 6 ml/s). The response surface method (RSM) was used to optimize FAME content. The results show that the capillary discharge reactor is possible to continuously produce 95.9 % methyl ester content (FAME- content) in a MeOH/oil molar ratio of 6.2:1, catalyst concentration of 1.2 wt%, applied voltage of 18 kV and flow rate of 4.6 ml/s. The power consumed in this process was 46.16 kJ/lit. These results indicate that the studied technology is able to continuously produce methyl ester with high conversion efficiency at low temperatures and with minimum amounts of inputs compared to common methods.

Continuous biodiesel production from acidic oil using a combination of acidic and alkaline composite catalytic membranes in flow-through membrane reactors

A comprehensive process of esterification for online separation transesterification for biodiesel production, with a yield of up to 97.52%.

Chaotic Transport in Three-Dimensional Reactors Operating in Open Flows for Continuous Biodiesel Production from Rapeseed Oil: Numerical and Experimental Comparative Study

Chaotic Transport in Three-Dimensional Reactors Operating in Open Flows for Continuous Biodiesel Production from Rapeseed Oil: Numerical and Experimental Comparative Study

Biodiesel production in a fixed bed reactor from Vernonia cinerea oil using calcined Pyrgostylus striatulus catalyst supported on activated carbon

ABSTRACT The current study had focused on continuous production of biodiesel from Vernonia cinerea seeds using a fixed bed reactor loaded with green catalyst. The free fatty acid (FFA) of the underexploited Vernonia cinerea seeds is very high. Two-phase solvent extraction (TPSE) methodology was implied for the extraction of oil to reduce the FFA and eliminate two-step transesterification process. At the experimental conditions of 60:40 n-hexane-to-methanol ratio, 65ºC temperature, and 4 hours of extraction time, 40% of Vernonia cinerea oil was obtained with FFA of 1.8%. The FFA of the oil got reduced by 78.5% by the implication of TPSE method. The characterization of the bio-oil was performed using FT-IR and GC-MS analysis. Pyrgostylus striatulus shells were calcined and supported on activated carbon. This was utilized as the green catalyst for biodiesel production. A complete analysis of the shells before and after calcination and after loading on activated carbon was studied using Hammett indicator, XRD, SEM, EDX, and BET analyses. Fixed bed reactor loaded with the calcined catalyst was utilized for the conversion of Vernonia cinerea oil and methanol into biodiesel. A maximum conversion of 96% was observed at the process conditions of 65ºC, 25:1 methanol-to-oil-molar ratio, 350-mm catalyst bed height and residence time of 6 hours. FT-IR analysis and 1HNMR analysis were performed to check the conversion of oil to biodiesel. The physio-chemical properties of methyl esters from Vernonia cinerea oil were analyzed. Findings of this research support that the produced biodiesel meets the ASTM standards indicating the fuel to be commercialized.

Response surface methodology for continuous biodiesel production from Jatropha curcas oil using Li/pumice as catalyst in a packed-bed reactor assisted with diethyl ether as cosolvent

A packed-bed catalytic configuration reactor using pumice granules loaded with lithium (Li/Pumice) as a heterogeneous catalyst was developed for biodiesel production in continuous. For this purpose, Jatropha curcas oil was used as an alternative feedstock to edible oils and diethyl ether was used as a cosolvent to eliminate the limitations of mass transfer between the phases. In this work, the response surface methodology was applied to optimize the fatty acid methyl esters (FAME) yield in biodiesel production. The flow rate (0.7–1.4 mL min−1), the methanol/oil molar ratio (6:1–20:1) and the cosolvent/methanol molar ratio (0.5:1–1.5:1) were the independent variables studied. The effects of these factors over the FAME yield using Li/Pumice as catalyst were evaluated according to a Box-Behnken design. The optimum conditions for the maximum FAME yield (100%) were 1.4 mL min−1, 20.0 methanol/oil molar ratio and 0.57:1 cosolvent/methanol molar ratio.

Use of dolomite catalyst in biodiesel production via transesterification of waste cooking oil in oscillatory baffled reactor

AbstractBiodiesel has recently gained popularity due to its environmental issues and the fact that it is generated from renewable resources. However, the cost of the synthesis of biodiesel is the major impediment to commercialization. The utilization of leftover cooking oils as raw material, the adaptation of a continuous transesterification process, and the use of cheap catalysts are the major possibilities for investigating the cost of biodiesel. In this work, a dolomite catalyst was prepared from natural dolomite rocks and used for the evaluation of continuous transesterification of biodiesel from oleic acid as a model compound of waste cooking oil (WCO). The dolomite catalyst was prepared by activation under vacuum at a surface area of 34.5 m2/g. The characterization tests showed good thermal stability of the catalyst and evolution of the CaO and MgO compounds at high concentrations. A kinetic study was conducted to obtain kinetic parameters of catalytic transesterification of the WCO. The kinetic experiments were carried out at 298–333 K, and residence time up to 80 min. The results presented that the catalytic transesterification is the first‐order reaction, and the activation energy was 43 kJ/mol. The oscillatory baffled reactor (OBR) was used to evaluate the dolomite catalyst for the continuous production of biodiesel via transesterification. The evaluation study was conducted at a methanol: oil mole ratio of 6:1 and the effect of different operation variables on oleic acid conversion to biodiesel was studied. These variables were temperature (323, 333, and 343 K), residence times (5–40 min), the amplitude of oscillation (2–8 mm), and frequency of oscillation (1, 2, 3, 4, and 4.3 Hz). The results showed an outstanding performance and stable activity of the dolomite catalyst as a conversion of 96% was obtained at 333 K, 4.3 Hz, 8 mm amplitude, and 40 min residence time.

Biodiesel production in a magnetically fluidized bed reactor using whole-cell biocatalysts immobilized within ferroferric oxide-polyvinyl alcohol composite beads

Magnetic whole-cell biocatalysts (MWCBs) constructed by immobilizing Bacillus subtiliscells within ferroferric oxide-polyvinyl alcohol composite beads were developed and employed to transesterify waste frying oil to biodiesel in a magnetically fluidized bed reactor (MFBR). Effective variables including biocatalysts concentration, reactant flow rate, magnetic field intensity and temperature were evaluated to enhance the transesterification. By coupling MFBR with MWCBs, continuous biodiesel production was achieved. Response surface methodology and Box-Behnken design were employed to predict the optimal conditions and the maximum biodiesel yield reached 89.0 ± 0.6% after 48 h under the optimized conditions. Furthermore, MWCBs displayed satisfactory stability and reusability in MFBR and still maintained a biodiesel yield of more than 82.5% after 10 cycles. Lastly, the fuel properties of the obtained biodiesel met the ASTM and EN standards. The present study revealed that the route of producing biodiesel over MWCBs in the MFBR system showed great potential for industrialization.

Fine-tuned fabrication parameters of CaO catalyst pellets for transesterification of palm oil to biodiesel

In recent years, the use of heterogeneous catalysts has gained increasing attention for biodiesel production. Among metal oxide catalysts, CaO powder is widely explored and considered to be a promising catalyst. However, the powder catalyst is inappropriate for continuous biodiesel production. Therefore, the catalyst pellet fabrication parameters related to its properties and biodiesel yield were investigated. Key results included the observation that catalysts produced using an Al2O3 binder possessed the highest catalytic activity compared to kaolin and diatomite supported catalysts, for calcination temperatures of 800 °C, possessing a comparable catalytic activity to the CaO powder. The CaO to Al2O3 mass ratio exhibited a significant effect on the surface area and total basicity. The highest biodiesel yield was obtained using the CaO-A(800)-3.5:1 catalyst due to the presence of several active crystal phases including CaO, Ca(OH)2 and CaSiO3 phases to accelerate the transesterification rate. These fabricated CaO catalyst pellets can be utilized as a catalyst for the continuous biodiesel production process.

Fabrication of novel microreactors in-house and their performance analysis via continuous production of biodiesel

Microreactors enhance biodiesel yields due to their more efficient mixing mechanisms and faster mass transfer rates than conventional batch processes. In this investigation, microreactors with different designs and geometries (four T-shaped with different lengths, one Y-shaped, and one Tesla-shaped) have been successfully fabricated at Fab Lab Bahrain using a high-resolution CO2 laser cutting machine. Then, the performances of these microreactors for the continuous production of biodiesel were tested and compared. The transesterification of the 9:1 molar ratio of methanol to oil was operated at a temperature of 60°C, with a 1.0 wt% NaOH catalyst. The performance of each microreactor for biodiesel synthesis was experimentally studied. The highest biodiesel yield was found to be 97.9%, with the Tesla-shaped microreactor at a residence time of only 4.85s, while the T- and Y- shaped microreactors give the highest percentage yield of 93.3% and 94.3%, respectively, with a residence time of 3.28s each. Online monitoring of the microchannel using optical imaging showed a mixing percentage of 97.6%, 97.87%, and 99.52% with T-, Y-, and Tesla- shaped microreactors, respectively, which consolidates the mixing effect's on developing the percentage yield of biodiesel.

Continuous biodiesel production from acidic oil using a combination of the acid-, alkali-catalyzed membrane and GO/PVDF separation membrane

An integrated process of esterification with phosphotungstic acid/poly (ether sulfone) (PWA/PES) membrane, transesterification with alkalized polysulfone (APSF) membrane and Graphene Oxide/poly (vinylidene fluoride) (GO/PVDF) separation membrane was carried out to produce biodiesel from acidic oil. At the first step, the PWA/PES membrane was introduced to catalyze the esterification reaction. The morphology, maximum pore size, porosity and catalytic esterification performance of PWA/PES membrane were investigated. After the esterification, products and reactants without reaction were put into the GO/PVDF separation membrane to soybean oil and other substances. The permeation mixture flux and soybean oil rejection of the GO/PVDF separation membrane is 597.89 L/m2·h and 98.02%, respectively. At the second step, the APSF membrane was added to catalyze the transesterification reaction in which the soybean oil reacted with methanol. The results showed that the esterification conversion was 98.6% and transesterification conversion was 91.2%. The main parameters of the biodiesel product obtained meet the Chinese Standard (GB/T 20828) and European Standard (EN 14214).