Optimization and sensitivity study of biodiesel synthesis from Jojoba oil using mixed-integer programming

Jojoba oil-based biodiesel is promising alternative fuel due to its versatile properties. Renewable transportation fuels are considered as promising alternatives to conventional fuels. The physical and chemical properties of these fuels enabled them to be used in modern internal combustion engines; this makes them attractive for use as direct replacements or as additives of fossil fuels. Jojoba oil is extracted from Jojoba seeds, and it is an excellent feedstock for biodiesel after the transesterification process. The plant is highly adaptable to harsh weather including salty water, desert, and hot temperatures; thus, it can be grown in Saudi Arabia. This research work comprises a detailed optimization study of biodiesel production from Jojoba oil using mixed-integer programming. golden section search method was used for the optimization and sensitivity study was conducted for reaction time and temperature. The result shows that 54.1 minutes and 47.5 °C are the optimized reaction time and temperature to produce biodiesel which is considerably low as compared to previous studies.     

Facile synthesis of layered sodium disilicates as efficient and recoverable nanocatalysts for biodiesel production from rapeseed oil

In this study, α, β and δ phases of layered sodium disilicates were synthesized and used as heterogeneous catalysts for transesterification of rapeseed oil with methanol to methyl esters (biodiesel). The catalysts were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) technique, Fourier transform infrared spectroscopy (FT-IR), N₂ adsorption-desorption, and thermogravimetric analysis (TGA-DTA). δ-Na₂Si₂O₅ showed better catalytic efficiency than the other two phases of sodium disilicate, and showed excellent activity at the optimized conditions. The transesterification conditions, such as the catalyst dosage, molar ratio of methanol to oil, reaction temperature and reaction time were investigated. The results revealed that with a catalyst loading of 4?wt%, methanol to oil ratio of 30:1, reaction temperature of 65?°C and reaction time of 3?h, conversion of biodiesel reached 97.8%.     

Modification of FAU zeolite as an active heterogeneous catalyst for biodiesel production and theoretical considerations for kinetic modeling

In this work, a high purity FAU-type zeolite catalyst was prepared from shale rock and modified as a heterogeneous efficient catalyst for biodiesel production from sunflower oil. The characterization properties for both of the prepared catalysts were determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), Brunauer–Emmett–Teller (BET), and Fourier-transform infrared spectroscopy (FTIR). The incipient wetness impregnation method was adopted for loading the catalyst with three base precursors: NaOH, KOH, and Ca(OH)3. Different factors affecting transesterification reaction onto modified Na-K-Ca-FAU zeolite were investigated such as; temperature (35, 45, 55, and 65 °C), catalyst concentrations (2, 3,4, 5, and 6 wt%) and the molar ratio of methanol to sunflower oil (3:1, 6:1, 9:1 and 12:1). The optimum conditions of transesterification reactions were obtained for reaction time (4 h) and agitation rate (700 rpm) in a batch reactor at 65 °C reaction temperature, 5% catalyst concentration, and a 9:1 M ratio of methanol to oil. The experimental results showed that the conversion of triglyceride in sunflower oil to fatty acid methyl ester (FIME) increased from 48.62 to 91.6% when the FAU zeolite was loaded with 15 wt% of the three bases. The properties of the produced biodiesel were evaluated within the standard performance ASTM D-6751. This study shows that the three base precursors (i.e., NaOH, KOH, and Ca(OH)3) were successfully loaded onto support FAU zeolite and functioned as excellent catalysts for biodiesel production. Theoretical considerations for kinetic modeling in the heterogeneous transesterification reaction were investigated using MATLAB programming. The experimental and theoretical considerations for kinetic modeling were fitted well.     

正交法探讨均相碱催化制备生物柴油的优化条件

以菜籽油为原料,甲醇钠为催化剂,二异丙醚为共溶剂,通过酯交换法制取生物柴油,并考察了醇油摩尔比、催化剂用量、共溶剂用量、反应时间和温度对生物柴油产率的影响.通过正交试验得出菜籽油与甲醇酯交换反应的最优条件为:醇油比为6:1,甲醇钠催化剂用量为油重的1.2%,共溶剂与油的摩尔比为1.2 :1,反应温度60℃,反应时间80min,低速120r/min搅拌强度下,转化率达到96.45%.制得的生物柴油各理化指标均符合美国和德国生物柴油测试标准.     

掺杂镧的固体碱MgO/SBA-15催化大豆油制备生物柴油

采用浸渍法制备了掺杂镧的固体碱MgO/SBA-15催化剂,将其用于大豆油酯交换制备生物柴油的反应。XRD表征结果显示,活性组分在载体SiO2骨架中高度分散。考察了不同镧镁物质的量比、焙烧温度和催化剂用量等因素对催化剂性能的影响,发现镧的引入有利于催化剂与反应物的接触,从而提高催化剂的活性;镧和镁物质的量之比为0.5∶1,催化剂焙烧温度700℃,焙烧时间3h,催化剂质量分数为3%,反应时间3h时,生物柴油的产率达到95%以上。     

Liquid–liquid equilibrium (LLE) study for six-component transesterification system

Transesterification of oils/triglycerides (TGs) with alcohol in the presence of catalyst has been the most commonly used process to produce biodiesel. Major limiting factors of conventional biodiesel transesterification process are phase separation and product purification. Precise and correct knowledge of the phase equilibrium behaviour is crucial for future industrial biodiesel reaction, separation and purification processes. For this purpose, it is important to consider the phase equilibrium behaviour in order to thoroughly understand the entire transesterification system for biodiesel production, which consists of six components. This work is to discuss on the liquid–liquid equilibrium (LLE) data of six-component system which involves TG, palm biodiesel (FAME), methanol (MeOH), glycerine (GLY), diglyceride (DG) and monoglyceride (MG). The phase equilibrium data of this system were determined experimentally through transesterification of crude palm oil (CPO). The experimental LLE data have been transposed into a pseudo-ternary diagram as TG–DG–MG + MeOH–GLY + FAME for better visualisation and understanding of the six-component system. Results showed that the transesterification of TG to FAME has formed a two-phase system where CPO-rich phase and MeOH-rich phase co-existed during the reaction. Due to immiscibility of CPO and MeOH, as well as the miscibility of FAME and MeOH, the LLE data suggested that at specific reaction operating condition, the reacted product (FAME) could be continuously removed by separating the MeOH phase from the CPO phase. This favours the forward transesterification reaction and eventually enhances the reaction efficiency to produce an oil-free FAME.     

A review of biodiesel production from microalgae

As the search for alternatives to fossil fuels continues, microalgae have emerged as a promising renewable feedstock for biodiesel. Many species contain high lipid concentrations and require simple cultivation—including reduced freshwater and land area needs—compared to traditional crops used for biofuels. Recently, technological advancements have brought microalgae biodiesel closer to becoming economically feasible through increased efficiency of the cultivation, harvesting, pretreatment, lipid extraction, and transesterification subsystems. The metabolism of microalgae can be favorably manipulated to increase lipid productivity through environmental stressors, and “green” techniques such as using flue gas as a carbon source and wastewater as a media replacement can lower the environmental impact of biodiesel production. Through life cycle assessment and the creation of process models, valuable insights have been made into the energy and material sinks of the manufacturing process, helping to identify methods to successfully scale up microalgae biodiesel production. Several companies are already exploring the microalgae industry, offsetting operating costs through isolation of co-products and careful unit operation selection. With numerous examples drawn from industry and the literature, this review provides a practical approach for creating a microalgae biodiesel facility.     

ZnO impregnated MgAl(O) catalyst with improved properties for biodiesel production: The influence of synthesis method on stability and reusability

ABSTRACT

A magnesium-aluminum layered double hydroxide was synthesized with co-precipitation method and zinc salt was impregnated on it. The final product was calcined and used as a catalyst in the transesterification reaction to produce biodiesel from waste cooking oil. Both MgAl hydrotalcite and Zn impregnated compound (Zn/MgAl(O)) were characterized using X-Ray Diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) techniques. High surface area and nanometric pore size of Zn/MgAl(O) was determined using Bruneure-Emmett-Teller N₂ physisorption technique. Another fully co-precipitated ZnMgAl mixed oxide was synthesized by and compared with Zn impregnated product in the transesterification reaction. The reactions were performed at 65°C using 9:1 methanol to oil ratio for 3?h. The biodiesel yields were measured by gas chromatography (GC). Leaching amounts of surface active components of as-synthesized mixed metal oxides were determined by EDS and ICP analysis of used catalyst. Zn impregnated catalyst showed 78.45% conversion of the fatty acid to methyl esters and just 1.16% leaching of Zn was observed, that is much lower than the diminishing in the co-precipitated compound. Finally, the reaction and leaching proofs and the effect of synthesis method on the firmness of catalyst were discussed.     

Design and analysis of biodiesel production from algae grown through carbon sequestration

This paper addresses the design and techno-economic analysis of an integrated system for the production of biodiesel from algal oil produced via the sequestration of carbon dioxide from the flue gas of a power plant. The proposed system provides an efficient way to the reduction in greenhouse gas emissions and yields algae as a potential alternative to edible oils currently used for biodiesel production. Algae can be processed into algal oil by various pathways. The algal oil can then be used to produce biodiesel. A flowsheet of the integrated system is synthesized. Then, process simulation using ASPEN Plus is carried out to model a two-stage alkali catalyzed transesterification reaction for converting microalgal oil of Chlorella species to biodiesel. Cost estimation is carried out with the aid of ICARUS software. Further economic analysis is performed to determine profitability of the algal oil to biodiesel process. The results suggest that, for the algal oil to biodiesel process analyzed in this study, factors such as choosing the right algal species, using the appropriate pathway for converting algae to algal oil, selling the resulting biodiesel and glycerol at a favorable market selling prices, and attaining high levels of process integration can collectively render algal oil to be a competitive alternative to food-based plant oils.     

Advances in carbon nanotubes as efficacious supports for palladium-catalysed carbon–carbon cross-coupling reactions

Since the 1970s, palladium-catalysed carbon–carbon (C–C) bond formation has made a critical impact in organic synthesis. In early studies, homogeneous palladium catalysts were extensively used for this reaction with limitations such as difficulty in separation and recycling ability. Lately, heterogeneous palladium-based catalysts have shown promise as surrogates for conventional homogeneous catalysts in C–C coupling reactions, since the product is easy to isolate, while the catalyst is reusable and hence sustainable. Recently, a better part of these heterogeneous palladium catalysts are supported on carbon nanotubes (Pd/CNTs), that have shown superior catalytic performance and better recyclability since the CNT support imparts stability to the palladium catalyst. This review discusses the wide variety of surface functionalization techniques for CNTs that improve their properties as catalyst supports, as well as the methods available for loading the catalyst nanoparticles onto the CNTs. It will survey the literature where Pd/CNTs catalysts have been utilized for C–C coupling reactions, with particular emphasis on Suzuki–Miyaura and Mizoroki–Heck coupling reactions. It will also highlight some of the important parameters that affect these reactions.     

Production of biodiesel as a renewable energy source from castor oil

The constantly increasing demand for energy can result in a huge crisis at the end of fossil fuels era. To prevent such an awkward situation, studies on finding alternatives have been seriously undertaken since the first oil crisis in the 1970s. Biodiesel, with a history of more than a century, has always been a potential candidate. In this research, the process of producing biodiesel from castor oil, which is a highly adaptable plant to Iran’s climates was studied. Methanol and castor oil as reactants with 10:1 molar ratio and sulfuric acid as catalyst with mass percent of 3 were allowed to react through trans-esterification reaction under mild conditions. The results from gas chromatography–mass spectrometry (GC–MS) showed the purity of more than 94 % esters for any conducted experiments which count as a success for an oil with more complicated structure than other raw vegetable oils. GPC analysis illustrated that the castor oil has a molecular weight of 1,068, which is almost three times that of colza oil. Some significant chemical and physical properties of the product, such as kinematic viscosity, flash point, pour point, etc. were calculated to approve conformity to ASTM D6751 standards. Eventually, the polluted emissions were measured by an Orsat gas analyzer. The outcomes completely corroborate the assumption which claims that adding biodiesel to conventional diesel fuels has a strong influence on lowering CO₂, CO, HC, and smoke.     

Biodiesel production using waste cooking oil: a waste to energy conversion strategy

In this study, biodiesel was produced using waste cooking oil that was discarded as a waste in the environment. The properties of the feedstock were determined using standard ASTM methods. The transesterification process was implemented to extract the biodiesel, and this process was optimized and standardized by selecting three different parameters: molar ratio (methanol:oil), catalyst concentration (KOH) and reaction temperature. The physicochemical properties of the biodiesel so produced were tested and analyzed using gas chromatography. Biodiesel and diesel were mixed in different volumetric ratios, and the exhaust emission characteristics of the blends were determined by testing the blends on a variable compression ratio engine. The study concluded that waste cooking oil has a great potential for waste to energy process. The highest yield of 93.8% was obtained by optimizing the process. Emission characteristics of CO for B50 blend showed a downward trend while NO _x emission was found to be greater for blending ratios above 10%. B10 showed the best results pertaining to lower NO _x and CO emissions.     

纳米晶镁铝水滑石制备机理及抗毒性研究

以尿素为沉淀剂制备纳米晶镁铝水滑石,考察不同镁铝比制备的纳米晶镁铝水滑石催化剂对大豆油酯交换的影响以及催化剂的抗水抗酸性和使用寿命,并探讨纳米晶镁铝水滑石的合成机理.随镁铝摩尔比增加,酯交换反应所需时间减少,当m(Mg2 ):m(Al3 )=3:1时,转化率高达94.2%;当m(Mg2 ):m(Al3 )=4:1时,使用寿命最长,可重复使用5次.纳米晶镁铝水滑石具有较强抗水抗酸性,故在进行酯交换反应中无须脱水脱酸.     

An experimental investigation on the performance,combustion and emission characteristics of a variable compression ratio diesel engine using diesel and palm stearin methyl ester

An attempt has been made to use biodiesel prepared from non-edible portion of palm oil as fuel of a conventional mono-cylinder compression ignition engine. The present experimental investigation takes into account the combined effect of using blends of diesel–palm stearin biodiesel as fuels and the compression ratio on different performance, combustion and emission characteristics of the said engine. The experiments have been carried out on a single-cylinder, direct injection diesel engine at varying compression ratio of 16:1–18:1 in four steps. It is observed that the brake thermal efficiency reduces by 7.9% when neat biodiesel is used instead of diesel. But, it increases with the increase in compression ratio for all the blends. Brake specific fuel consumption and exhaust gas temperature increase with the addition of biodiesel to diesel and also with the increase in compression ratio. Heat release rate decreases with biodiesel, and it is minimum at the rated compression ratio of 17.5:1 for all the fuels considered here. On the other hand, ignition delay is found to be more with neat diesel, and it increases with the decrease in compression ratio. Significant reductions in emissions of carbon monoxide (CO), hydrocarbon (HC) and smoke are observed with biodiesel, while the emissions of oxides of nitrogen (NO_x) and carbon dioxide (CO₂) increase. The decrease in compression ratio increases the emissions of CO, HC and smoke, but the emissions of NO_x and CO₂ decrease with the decrease in compression ratio.     

Parameters affecting oleochemical production from waste bleaching earth via alcoholysis

The edible oil industry is one of the largest industries in the world. In the edible oil refining process, large amounts of waste are discarded every day. Evaluation of these wastes is vital for environmental issues. Most of this waste is due to the bleaching process in which bleaching earths are largely used. Due to its high adsorption capacity, bleaching earth adsorbs oil nearly 40% of its weight. In order to evaluate this waste for oleochemical production, alcoholysis reactions were investigated. Parameters affecting the reaction, such as catalyst type and amount, alcohol type, alcohol:oil molar ratio and temperature, were investigated. The reactions were conducted in the presence of different catalysts such as NaOH, NaOCH₃ and homogeneous alkali polymeric gel catalyst (HAPJEK) and performed at a temperature range of 60–78°C and in the presence of a catalyst (1–2% based on oil weight) at alcohol:oil molar ratios of 5:1–7:1. Based on optimisation by response surface methodology (RSM), the critical synthesis conditions for 210 min reaction time with a maximum of 85.8% methyl ester content were determined as temperature: 68.4°C, catalyst amount 1.5% based on oil weight and methanol/oil molar ratio: 6.4.     

Advances in biodiesel fuel for application in compression ignition engines

The importance of biodiesel as a renewable and economically viable alternative to fossil diesel for applications in compression ignition (CI) engines has led to intense research in the field over the last two decades. This is predominantly due to the depletion of petroleum resources, and increasing awareness of environmental and health impacts from the combustion of fossil diesel. Biodiesel is favoured over other biofuels because of its compatibility with present day CI engines, with no further adjustments required to the core engine configurations when used in either neat or blended forms. Studies conducted to date on various CI engines fuelled with varying biodiesel types and blends under numerous test cycles have shown that key tailpipe pollutants, such as carbon monoxide, aromatics, sulphur oxides, unburnt hydrocarbons and particulate matters are potentially reduced. The effects of biodiesel on nitrogen oxides emission require further tests and validations. The improvement in most of the diesel emission species comes with a trade-off in a reduction of brake power and an increase in fuel consumption. Biodiesel’s lubricating properties are generally better than those of its fossil diesel counterpart, which result in an increased engine life. These substantial differences in engine-out responses between biodiesel and fossil diesel combustion are mainly attributed to the physical properties and chemical composition of the fuels. Despite the purported benefits, widespread adoption of biodiesel usage in CI engines is hindered by outstanding technical challenges, such as low temperature inoperability, storage instabilities, in-cylinder carbon deposition and fuel line corrosion. It is imperative that these issues are addressed appropriately to ensure that long-term biodiesel usage in CI engines does not negatively affect the overall engine durability. Possible solutions range from biodiesel fuel reformulation through feedstock choice and production technique, to the simple addition of fuel additives. This calls for a more strategic and comprehensive research effort internationally, with an overarching approach for co-ordinating sustainable exploitation and utilisation of biodiesel. This review examines the combustion quality, exhaust emissions and tribological impacts of biodiesel on CI engines, with specific focus on the influence of biodiesel’s physico-chemical properties. Ongoing efforts in mitigating problems related to engine operations due to biodiesel usage are addressed. Present day biodiesel production methods and emerging trends are also identified, with specific focus on the conventional transesterification process wherein factors affecting its yield are discussed.     

Sustainability assessment for biodiesel production via fuzzy optimisation during research and development (R&D) stage

Biodiesel is regarded as an important renewable fuel for meeting the global future energy demand and resolving the environmental problems (e.g. global warming). Despite its known advantages, it is still very critical to assess the sustainability of biodiesel production prior to greater expansion for commercialisation. Early hazard assessment when the process is still under development and design is very beneficial as process modifications to eliminate or reduce hazards can be made easier at lower costs. In this paper, inherent safety, health and environment (SHE) and economic performance (EP) analysis is conducted for biodiesel production during the earliest process lifecycle which is named as research and development (R&D) stage. Prior to the assessment, eight biodiesel production pathways via base-catalysed, acid-catalysed, enzymatic and supercritical transesterification using fresh or waste oil are classified. The inherent SHE assessments are conducted using the renowned methods of the Prototype Index of Inherent Safety (PIIS), Inherent Occupational Health Index (IOHI) and Inherent Environmental Toxicity Hazard (IETH) for inherent safety, health and environmental friendliness, respectively. The EP assessment is done using a proposed costing assessment based on operating cost and revenue. A systematic framework for assessing alternative biodiesel production pathways during the R&D stage is presented. Fuzzy optimisation approach is used to assess the pathway candidates based on multiple objectives of inherent SHE and EP. From the assessment result, it is found that biodiesel production based on enzymatic transesterification using waste oil is the most desirable pathway. Following the result of the assessments, several improvement actions for inherent SHE in biodiesel production are proposed and discussed.     

Supported catalysts for heterogeneous electro-Fenton processes: Recent trends and future directions

Extremely low pH requirement and additional sludge management for the homogeneous electro-Fenton (EF) process necessitated the development of heterogeneous electro-Fenton (HEF) reactions that utilize solid catalysts that can be recovered and reused. In the recent decades, supported catalysts have immensely attracted researchers owing to the outstanding physical, chemical, and electronic properties of the supports that benefit the EF process by enhancing the removal efficiency, reducing reaction time, and extending the operational pH range. This review enlightens the readers about various materials that have been used for supporting the catalysts, their importance, method of impregnation, and optimum conditions required to attain maximum pollutant removal. From the wide array of catalysts reviewed, porous supports with a high surface area such as activated carbon, biochar and fibres adsorbs the pollutants near their surface facilitating enhanced Fenton reactions and degradation of pollutants. Alginate-based catalysts can be prepared by a simple procedure and exhibit good degradation efficiency when used in batch and continuous EF reactors. Zeolite-based catalysts are structurally stable and display promising results for successive cycles. The flexible and conductive nature of fibre-based supports performs the dual role as a catalyst and cathode. The highly stable and conductive properties of graphene and carbon nanotubes promote electron transfer, much required for continuous EF reactions.     

Hydrogen production through catalytic low-temperature bio-ethanol steam reforming

As a provider of our energy requirements, hydrogen seems to be one of most promising fuels, in particular when used to feed PEM fuel cells. When produced from a renewable source, it has got the potential to reduce the dependence on non-renewable fossil fuels and lower the amount of harmful emissions. Ethanol steam-reforming (ESR) reaction is an interesting option to obtain a H₂- and CH₄-rich stream with a low content of CO, combining the deep knowledge of the technology with the advantage of the biomass-derived feedstock. Thermodynamic analysis has indicated that the most interesting operating range to enhance the H₂ production and minimize CO and coke formation requires low pressure, high temperature, and high water-to-ethanol molar ratio. On the other hand, despite its endothermic nature, ESR could be carried out at low temperature, to increase overall thermal efficiency, even if at these conditions the catalyst's deactivation, due to coking and sintering phenomena, is not negligible. The main objective of this study is to investigate on the activity, stability, and durability of bimetallic Pt–Ni and Pt–Co catalysts supported on CeO₂ for low-temperature bio-ESR reaction. The catalysts have been prepared through different methods and with an optimized metal's content. They have also been characterized with various physico-chemical characterization tests, and the catalytic studies have been carried out in a lab-scale apparatus. While evaluating the effects on the catalysts' performances of preparation method, reaction temperature, space time, and water-to-ethanol molar ratio, the selected catalysts were found effective for the production of H₂ by steam reforming at low temperature. In particular, the Pt/Ni/CeO₂ catalyst shows a perfect agreement with equilibrium calculations yet at low contact times, although some carbon deposition occurs. Also the cobalt-based catalysts appear attractive. The relative rates of carbon growth versus gasification have been studied, and ascending water contents were used to study the effect of steam addition in the feed stream. An in-depth investigation of the reaction mechanism and the evaluation of the kinetic parameters will be crucial to complete the study of the proposed process.     

Use of 3D printing for biofuel production: efficient catalyst for sustainable biodiesel production from wastes

This work deals with the sustainable biodiesel production from low-cost renewable feedstock (waste and non-edible oils) using a heterogeneous catalyst constituted by potassium loaded on an amorphous aluminum silicate naturally occurring as volcanic material (pumice). The main challenge to biodiesel production from low-quality oils (used oils and greases) is the high percentage of free fatty acids (FFAs) and water in the feedstock that causes undesirable side reactions. The catalytic materials studied were tested in the transesterification reaction when using low-quality oils containing a high proportion of free fatty acids (FFAs) and water. Results indicated that the amount of acid and basic sites on the catalytic surface increases upon increasing potassium loading in the catalyst, displaying better performance for biodiesel production. Indeed, the modification of the aluminum silicate substrate upon potassium incorporation results in a catalytic material containing both acidic and basic sites, which are responsible for both triglycerides transesterification and FFA esterification reactions. The studied catalyst not only showed good performance in the biodiesel production reaction but also good tolerance to FFA and water contained in the feedstock for biodiesel production. The catalytic material was microstructured by 3D printing in order to design a catalytic stirring system with high mechanical strength, efficient and reusable. The use of 3D printing in biofuel production is a novelty that brings good solutions for catalyst production.