Intensification of continues biodiesel production process using a simultaneous mixer- separator reactor

Nowadays, Biodiesel as an alternative, sustainable and less toxic fuel has been accepted by both researchers and industry. Developing process intensification reactors with the aim of reaching more efficient process has captured the attention of many researchers recently. In order to examine a novel reactor for biodiesel production using Waste Cooking Oil as a cost-effective feedstock, and KOH as an efficient homogeneous catalyst, the present study was developed to investigate three effective parameters (Oil flow rate, catalyst concentration and reaction temperature) focusing on transesterification reaction yield in the Simultaneous Mixer-Separator (SMS) reactor, designed and fabricated exclusively for biodiesel production at Tarbiat Modares University (TMU). As the findings indicated, rising the flow rate presented an increasing trend up to 15 mL/min and a decreasing trend was found after this level. Also, catalyst concentration up to 1% w/w showed an increasing trend which was significant. Analysis of reaction temperature showed that at 60^°C the maximum yield is obtained. Furthermore, 15 mL/min oil flow rate, 1% w/w KOH concentration and 60^?C were selected as the optimal reaction conditions for continuous biodiesel production. At this point, the produced biodiesel followed by the purification step reached the yield of 96%. The produced biodiesel physicochemical properties were found to meet ASTM D6751 standard. All in all, continuous production capability, higher productivity, simultaneous separation of products, and the successful handling of waste resources distinguish the SMS reactor as a potential and efficient process intensification reactor.     

Improved biodiesel manufacture at low temperature and short reaction time

Biodiesel, which is derived from oil/fat by transesterification with alcohol, has attracted considerable attention over the past decades due to its ability to subsidise fossil fuel derived energy as a renewable and carbon neutral fuel. Several approaches for biodiesel fuel production have been developed, among which transesterification using a catalyst gives high yields of methyl ester. This method has therefore been widely utilized for biodiesel production in a number of countries. In this study, a Downflow Liquid Contactor Reactor (DLCR) has been used for the liquid–liquid transesterification reaction of sunflower oil with alcohol with extraordinary results. The reactor provides great potential for chemical reactions, which are normally limited by mass transfer and possesses a number of distinctive advantages over conventional multiphase reactors. Inside the reactor a high velocity liquid jet stream is produced which generates powerful shear and energy, causing vigorous agitation in the upper part of the reactor. The high mixing intensity in the DLCR enabled the manufacture of biodiesel to European Standard EN14214 (ester content 96.5%) in 2.5 min at 40 °C with 0.43 wt.% alkali catalyst and alcohol to oil molar ratio of 4.5 to 1.0. The separation of FAME from glycerol is done by gravity settling only without water washing. The effect of the alcohol type (methanol, ethanol) on biodiesel yield was also investigated. The process offers the advantage of continuous large scale production with limited reactor volume.     

TiO2/Al2O3 membrane reactor equipped with a methanol recovery unit to produce palm oil biodiesel

In this study, the central composite design of the response surface methodology was employed to investigate the effects of reaction temperature, catalyst concentration and cross flow circulation velocity on the production of biodiesel in a TiO₂/Al₂O₃ membrane reactor. High‐quality palm oil biodiesel was produced by combination of alkali transesterification and separation processes in the ceramic membrane reactor. The optimum conditions for the conversion of palm oil to biodiesel in the ceramic membrane reactor were as follows: 70°C reaction temperature, 1.12 wt% catalyst concentration and 0.211 cm s^{? 1} cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. Copyright © 2010 John Wiley & Sons, Ltd.     

Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran and co-workers for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet-stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO₂ production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.     

Bio-fuel reformation for solid oxide fuel cell applications. Part 1: Fuel vaporization and reactant mixing

A new configuration of a mixing chamber integrated with a customized porous nozzle has been developed to completely vaporize heavy hydrocarbon fuels (e.g., diesel, biodiesel) and achieve homogenous mixing of fuel/air/steam. This proposed configuration suppresses hydrocarbon thermal pyrolysis and solid carbon formation in the fuel vaporization step. The porous nozzle promotes the micro-explosion of emulsified fuel and accelerates secondary atomization to reduce the droplet size. The mixing chamber with customized nozzle was integrated in a single-tube reformer system in order to analyze its effect on diesel and biodiesel auto-thermal reforming (ATR). It has been demonstrated that the customized nozzle not only improved the hydrogen production rate and the reforming efficiency, but it also stabilized the chemical reactions within the reformer and prevented the reactor inlet from high temperature sintering. For diesel ATR, this mixing chamber–reformer combination enabled operation at relatively low reformer temperature without forming solid carbon. This study is one component of a three-part investigation of bio-fuel reforming, also including biodiesel (Part 2) and biodiesel–diesel blends (Part 3).     

Fuel properties of biodiesel from vegetable oils and oil mixtures. Influence of methyl esters distribution

In this work, the quality of biodiesel produced by basic transesterification from several vegetable oils (soybean, rapeseed, sunflower, high oleic sunflower, Cynara Cardunculus L., Brassica Carinata and Jatropha Curca) cultivated in Extremadura has been studied in detail. The influence of raw material composition on properties such as density, viscosity, cetane number, higher heating value, iodine and saponification values and cold filter plugging point has been verified. Other biodiesel properties such as acid value, water content and flash and combustion points were more dependent on characteristics of production process. Biodiesel produced by rapeseed, sunflower and high oleic sunflower oils transesterification have been biofuels with better properties according to Norm EN 14214. Finally, it has been tested that it is possible to use oils mixtures in biodiesel production in order to improve the biodiesel quality. In addition, with the same process conditions and knowing properties of biodiesel from pure oils; for biodiesel from oils mixtures, its methyl esters content, and therefore properties dependent this content can be predicted from a simple mathematical equation proposed in this work.     

Biodiesel separation and purification: A review

Biodiesel as a biodegradable, sustainable and clean energy has worldwide attracted renewed and growing interest in topical years, chiefly due to development in biodiesel fuel and ecological pressures which include climatic changes. In the production of biodiesel from biomass, separation and purification of biodiesel is a critical technology. Conventional technologies used for biodiesel separation such as gravitational settling, decantation, filtration and biodiesel purification such as water washing, acid washing, and washing with ether and absorbents have proven to be inefficient, time and energy consumptive, and less cost effective. The involvement of membrane reactor and separative membrane shows great promise for the separation and purification of biodiesel. Membrane technology needs to be explored and exploited to overcome the difficulties usually encountered in the separation and purification of biodiesel. In this paper both conventional and most recent membrane technologies used in refining biodiesel have been critically reviewed. The effects of catalysts, free fatty acids, water content and oil to methanol ratios on the purity and quality of biodiesel are also examined.     

A systematic multivariate analysis of the supercritical synthesis of soy biodiesel using 92.8% w/w hydrated ethanol

The transesterification of vegetable oils under supercritical conditions has been identified as a viable alternative for efficient biodiesel synthesis and has the potential for industrial applications. In the present study, a multivariate analysis was used to optimize the supercritical transesterification of soybean oil and hydrated ethanol (92.8% w/w). The following variables were evaluated: reaction time, temperature, ethanol/oil molar ratio and the ratio between the reagent volume and reactor volume. The reactions were conducted according to a Doehlert design using four variables in a reactor specifically designed for this purpose. Glass windows positioned at the ends of the reactor allowed for the monitoring of the phases in the system at both the critical point and the supercritical environment. Both a mathematical linear regression model and response surface were created and used to determine the optimal synthesis conditions. An ester content of greater than 97.3% which was estimated using the optimized experimental conditions (320 °C, 50 min, ethanol/oil 49:1, reagent to reactor volume ratio of 60% and pressure lower than 20 MPa) indicated that biodiesel synthesis can be performed with high yields using hydrated bioethanol under supercritical conditions. The effects of temperature on polyunsaturated esters containing two and three carbon double bonds were also evaluated. The advantages of a supercritical synthetic route are that it requires neither catalysts nor washing water during the purification stages, produces purer glycerin than conventional processes and permits the re-use of ethanol without preliminary dehydration, which simplifies the overall process and has a low environmental impact.     

Pressurized ultrasonic production of biodiesel from Jatropha oil: optimization and energy analysis

The present study deals with the development of a biodiesel production reactor based on pressurized ultrasonic cavitation technique. Transesterification of Jatropha oil takes place by passing low-frequency ultrasonic irradiation in the reaction mixture flowing at pressurized conditions in the sonochemical reactor. Reaction variables such as reaction time, molar ratio, catalyst concentration, and pressure of the reaction mixture were investigated to find the optimal parameters for biodiesel production. The energy requirement decreases with increase in pressure. Very low value of Specific Energy Consumption (0.018 kWh/kg) and significantly high value of Energy Use Index (598.83) are obtained when the pressure of reaction mixture is 15 bar. Increasing the pressure thereafter, leads to nominal gains. Ultrasonic irradiation at high-pressure condition has an additional advantage of rapid reaction and lower requirement of alcohol to oil molar ratio and catalyst concentration. Fifteen bar pressure is optimal for biodiesel production.     

Biodiesel production from Cholrella minutissima microalgae: Kinetic and mathematical modeling

In the present work, a new and pioneering hybrid technology, called hydrodynamic-cavitation reactor, was established and investigated to proof the feasibility for the biodiesel production from Chlorella minutissima microalgae. The process parameters such as inlet pressure (A), molar ratio (B), catalyst concentration (C), and reaction time (D) have been investigated over the biodiesel yield from Chlorella minutissima microalgae. Box–?Behnken design was applied to develop the second- order polynomial model. The error between experimental values and model prediction was found to be less than 10%. Interactive effects of process variables on the biodiesel yield from Chlorella minutissima microalgae was studied using contour graphs. Inlet pressure of 4 bar, molar ratio of 1: 30, catalyst concentration of 1.3%, and reaction time of 40 min produced 99% of biodiesel yield. Further, a kinetic model has also been developed and considers the transesterification reaction to be a second-order reversible, first order with respect to each of the reactants and products. Estimated values of kinetic constants are k₁ = 0.00014 L min/mol and k₂ = 0.035 L min/mol.     

Biodiesel production from Nerium oleander (Thevetia peruviana) oil through conventional and ultrasonic irradiation methods

In the present research work, Nerium oleander oil has been used as raw material for producing biodiesel using both ultrasonic transesterification and a magnetic stirrer method. A two-step transesterification process was carried out for optimum condition of 0.40% V/V methanol to oil ratio, 1% V/V H₂SO₄ catalyst, 55°C temperature, and 60 min reaction time followed by treatment with 0.2% V/V methanol to oil ratio, 1% V/W KOH alkaline catalyst, 55°C temperature, and 60 min reaction time. The process is repeated with an ultrasonic method at the frequency of 28 kHz using ultrasonic horn type reactor (50 W) for about 10–15 min. Biodiesel obtained from ultrasonic method and magnetic stirrer was then compared for their percentage yield and physiochemical properties. Ultrasonic transesterification process gave a maximum yield of 97% by weight of oleander biodiesel along with improved physiochemical characteristics. Therefore, it is concluded that ultrasonic method is the most effective method for converting crude oleander oil into biodiesel.     

Biodiesel production in a serpentine minireactor—Effect of flow distribution

The present work aims to find out the influence of flow pattern on pressure drop and fatty acid methyl ester (FAME) yield in a reactive system. Experiments are carried out with Jatropha oil and methanol by using potassium hydroxide (KOH) as catalyst for biodiesel production in two serpentine minireactors made of glass capillary of 2‐mm internal diameter. One is having a circular cross section, and the other is annulus. Slug flow, slug with droplet flow, and dispersed flow are observed in both the reactors. Effects of flow distribution on pressure drop and FAME yield have been studied. FAME yield of 98.5% is observed in both reactors for a molar ratio 20 (methanol to Jatropha oil), and the time for this yield in the first reactor is 16.6 minutes and that for the second reactor is 7.7 minutes. Higher yield also resulted in lower pressure drop due to lower viscosity of biodiesel in comparison with oil.     

Analysis of blended fuel properties and engine performance with palm biodiesel–diesel blended fuel

Depleting fossil fuel sources accompanied by continuously growing energy demands lead to increased interest in alternative energy sources. Blended biodiesel–diesel fuel has been approved as a commercial fuel at a low blending ratio. However, problems related to fuel properties are persistent at high blending ratios. Hence, in this study, the feasibility of biodiesel produced from palm oil was investigated. Characterization of blended fuel properties with increasing palm biodiesel ratio is conducted to evaluate engine performance test results. The qualifying of blended fuel properties was used to indicate the maximum blending ratio suitable for use in unmodified diesel engines according to the blended fuel standard ASTM D7467. The property test results revealed that blended fuel properties meet blended fuel standard requirements at up to 30% palm oil biodiesel. Furthermore, blending is efficient for reduction of the pour point from 14 °C for unblended biodiesel to less than 0 °C at a 30% biodiesel blending ratio. However, the energy content reduces by about 1.42% for each 10% increment of biodiesel. Engine test results demonstrated that there was no statistically significant difference for engine brake thermal efficiency among tested blended fuels compared to mineral diesel, and the lowest engine cyclic variation was achieved with blended fuel B30.     

海藻生物燃料产业化开发的进展

海藻种类多样、光合作用效率高、生长周期短、生物产量高、自身合成油脂能力强,同时还能大量吸收CO2,是制备生物柴油最佳的生物质原料之一。国内外对海藻生物燃料技术的研发均取得一定成果。海藻生物柴油的生产过程主要包括海藻大规模培养、海藻油萃取、酯交换反应、生物柴油后处理4个步骤,而最重要的是海藻的大规模培养。光生物反应器已成为高效、快速、大量培养藻类的关键没备,其一般分为开放式和封闭式两种。AlgaeLink NV公司的海藻光生物反应器是目前世界上唯一已商业化的小型装置。我国企业采用自主研发的反应器装置,通过对环境条件因素进行控制,在技术上已达到海藻含油率40％,日产量1～1．4kg／m^3。当海藻含油率达到60％,日产量平均达到3kg／m^3以上时,海藻生物柴油的生产成本将接近石油柴油的批发价,海藻生物柴油产业将成为一个新兴的替代能源产业。     

Improving the economic feasibility of biodiesel production from microalgal biomass via high-value products coproduction

Microalgal biodiesel has emerged as a promising fuel source, but has still not been adopted commercially. One of the several inherent challenges is its high production cost, which mandates the need to develop an integrated process to produce other valuable coproducts economically. This article combines life cycle assessment and preliminary life cycle cost assessment of a proposed biorefinery, in which a high value product, β-carotene, is coproduced from microalgae with biodiesel. The GaBi 6 environmental management software was employed to investigate the environmental impact associated with the production life cycle. The mass flow rates and the energy consumed in all stages of biodiesel and β-carotene coproduction for the functional unit of 1 kg of biodiesel were assessed. When the coproduction of β-carotene was not taken into consideration, the total energy input for a functional unit of 1.0 kg biodiesel/m²/y and the net energy ratio, that is, energy returned on energy invested were estimated to be 128.1 GWh/y and 0.27, respectively. The life cycle cost analysis showed that although the total production cost associated with coproduction of β-carotene from Dunaliella salina was higher than that of the sole production of biodiesel, it generates a hiked revenue of up to $37 million/y. Over the system lifetime of 10 years, the sole production of biodiesel showed a loss of US$345 million per functional unit, whereas the coproduction of β-carotene achieved a net profit of US$120.7 million per functional unit. This work clearly showed that the coproduction of β-carotene with biodiesel from D. salina overcomes the cost-ineffectiveness resulting from the production of biodiesel alone.     

The utilization of waste egg and cockle shell as catalysts for biodiesel production from food processing waste oil using stirring and ultrasonic agitation

The use of calcined egg and cockle shell as heterogeneous solid catalysts for a transesterification reaction to produce biodiesel from food processing waste has been investigated in this work. The CaO catalysts were obtained from the calcination of egg and cockle shell and were characterized by surface analysis, X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The experiments employed stirring and ultrasonic agitation, which proved to be a time-efficient approach for biodiesel production from food processing waste oil. A response surface methodology (RSM) was used to evaluate the effects of the process variables methanol to oil molar ratio, catalyst concentration, and reaction time on biodiesel production. The optimal % fatty acid methyl ester values obtained when using egg and cockle shells as catalysts were found to be 94.7% and 94.4% when the methanol to oil molar ratios were 9.3:1 and 8.5:1, egg and cockle shell catalyst mass fraction percentages were 3.8% and 3.5%, and reaction times were 47 and 44 min, respectively. The study has shown that ultrasonic agitation might be employed in a practical pilot reactor for biodiesel production.     

基于微藻资源化利用的碳减排技术

微藻具有光合效率高、零净碳值、生长周期短、易培养、油含量高等优点,是一种极具前景的生物柴油原料。将微藻资源化利用与碳减排耦合的微藻生物柴油技术研究已受到政府和企业的广泛关注。综述了微藻高效固定CO2技术中微藻种类的筛选、培育、生长反应器及其系统的开发,微藻资源化利用的技术种类,展望了基于微藻资源化利用的碳减排技术的发展前景。     

Bio-fuel reforming for solid oxide fuel cell applications. Part 2: Biodiesel

Biodiesel is considered as a renewable hydrogen source for solid oxide fuel cells (SOFCs). This study contributes to a fundamental understanding of biodiesel autothermal reforming (ATR), which has not yet been widely explored in the open literature. Ultra-low sulfur diesel (ULSD) ATR is established as a baseline for this analysis. This work applies a micro-soot meter based on a photo-acoustic method to quantify the condensed carbon from a single-tube reactor, and uses a mass spectrometer to measure the effluent gas composition under different operating conditions (reformer temperature, steam/carbon ratio, oxygen/carbon ratio, and gas hourly space velocity). The key objective is to identify the optimum operating environment for biodiesel ATR with carbon-free deposition and peak hydrogen yield. Thermodynamic analysis based on the method of total Gibbs free energy minimization is used to evaluate the equilibrium composition of effluent from the reformer. The experimental investigations complimented with this theoretical analysis of biodiesel ATR enable effectively optimizing the onboard reforming conditions. This study is one component of a three-part investigation of bio-fuel reforming, also including fuel vaporization and reactant mixing (Part 1) and biodiesel–diesel blends (Part 3).     

Biodiesel from different oil using fixed-bed and plug-flow reactors

In this study, a pilot scale of 100 t/year biodiesel production system, mainly consisting of a fixed-bed and a down-stream plug-flow reactors, was setup to test different feedstock oils, especially a kind of high-acidified oil, trap grease, for their feasibility as biodiesel feedstock in China. The tested oils include three kinds of typical oil from Guangdong Province, China: rapeseed oil, Chinese wood oil, and trap grease. At the same time the optimum residence time for a plug-flow reactor to perform transesterification reaction was investigated in this study. At the temperature of 65 °C, methanol/oil molar ratio of 6:1 and KOH load of 1.2 wt% of oil, the optimum residence time was found to be 19 min. A type of ion-exchange resin was used to fill in the fixed-bed reactor and used as the esterification catalyst for pretreating on the high-acidified oil. For the fresh catalyst, the acid value of trap grease could be reduced from 114 mg KOH/g to about 2 mg KOH/g after 13 h at temperature 75 °C, catalyst load of 15 wt% of oil, methanol addition of 20 wt% of oil. The lifetime test for the catalyst indicated that its life is over 30 days. The quality of biodiesel derived from three feedstock oils is compared with newly published China BD100 standard of GB/T20828-2007. A comparison of the results reveals that the biodiesel generated through this system could satisfactorily meet China BD100 standard. It indicates that the designed process in this system has a good adaptability for different kinds of oil.     

Recent trends,opportunities and challenges of biodiesel in Malaysia: An overview

Energy supply and its security issues have been the topic of interest lately. With growing environmental awareness about the negative implications brought by excessive usage of fossil fuels, the race for finding alternative energy as their substitutions is getting heated up. For now, renewable energy from biodiesel has been touted as one of the most promising substitutions for petroleum-derived diesel. Combustion of biodiesel as fuel is more environment-friendly while retaining most of the positive engine properties of petroleum-derived diesel. Production of biodiesel is also a proven technology with established commercialization activities. The huge potential of biodiesel coupled with the abundance of palm oil which is one of the most cost-effective feedstocks for biodiesel is responsible for the pledging of Malaysia to become the leading producer of high quality biodiesel in the region. Currently, total approved installed capacity of biodiesel production in Malaysia equals to almost 92% of the world biodiesel production output in 2008. While Malaysia does indeed possessed materials, technologies and marketing superiority to vie for that position, many more challenges are still awaiting. The price restriction, provisions controversy, escalating non-tariff trade barriers and negligible public support need to be addressed appropriately. In this review, Malaysia's previous and current position in global biodiesel market, its future potential towards the prominent leading biodiesel status and major disrupting obstacles are being discussed. The feasibility of utilizing algae as the up-and-coming biodiesel feedstock in Malaysia is also under scrutiny. Lastly, several recommendations on the roles played by three major forces in Malaysia's biodiesel industry are presented to tackle the shortcomings in achieving the coveted status by Malaysia. It is hope that Malaysia's progress in biodiesel industry will not only benefit itself but rather as the role model to catalyst the development of global biofuels industry as a whole.