Biodiesel Current Technology: Ultrasonic Process a Realistic Industrial Application (original) (raw)

Four processes to make biodiesel from fresh cooking oil/ used cooking oil (referred as triglycerides) using basic or acidic or any other catalyst are: Direct use and Blending, Microemulsions, Thermal Cracking (Pyrolysis) and Transesterification. Technical assessment of all the processes is carried out and discussed here including advantages and limitations. The most commonly used method is transesterification of vegetable oils/animal fats with an alcohol in the presence of a catalyst. Detailed discussion on the process of transesterification has been done in this paper. Transesterification can be further classified in accordance with type of catalysts used, homogenous catalysts and heterogeneous catalyst and other as discussed in detail below. There are some emerging new techniques that can be used for production of biodiesel or for improving the quality of biodiesel being produced or to lower its cost, for ex. Use of biocatalyst (enzymes) as transesterification catalyst, transesterification using ultrasonic technique, use of waste cooking oil/ production of oil through algae as raw material respectively, that are being discussed in this paper.

Biodiesel has gained worldwide popularity as an alternative energy source due to its renewable, non-toxic, biodegradable and non-flammable properties. It also has low emission profiles and is environmentally beneficial. Biodiesel can be used either in pure form or blended with conventional petrodiesel in automobiles without any major engine modifications. Various non-edible and edible oils can be used for the preparation of biodiesel. With no competition with food uses, the use of non-edible oils as alternative source for engine fuel will be important. Among the non-edible oils, such as Pongamia, Argemone and Castor, Jatropha curcas has tremendous potential for biodiesel production. J. curcas, growing mainly in tropical and subtropical climates across the developing world, is a multipurpose species with many attributes and considerable potentials. In this article, we review the oil extraction and characterization, the role of different catalysts on transesterification, the current state-of-the-art in biodiesel production, the process control and future potential improvement of biodiesel production from J. curcas.

Biodieselismainlyproducedbytransesterificationreactionbetweenlipidfeedstocksuchasvegetable oil oralgaloilandalcohol.Consideringthedepletionofconventionalfossilfuel,biodieselisgaining more attentionasarenewable,sustainableandenvironmentalfriendlyfuel.Heterogeneouscatalysts are mostlyappliedintransesterificationreactionduetomanyadvantagessuchaseasycatalyst separationandreusability,improvedselectivity,reducingprocessstagesandcosteffective.Biodiesel process facesvariousproblemsrelatedtoimmisciblenatureofoilandalcoholleadstopoormass transfer rate.Thisrequireslongreactiontime,highercatalystconsumption,highermethanol-oilmolar ratio, hightemperatureandhighstirringrate.Thisreviewdiscussesthatthelatestadvancesin ultrasonicassisttransesterificationreactionwiththeuseofheterogeneouscatalyststoproduce biodieselwithcosteffective.Ultrasonicenergycanemulsifythereactantstoreducethecatalyst requirement,methanol-oilratio,reactiontimeandreactiontemperature.

Triglycerides are the main constituents of lipids, which are the fatty acids of glycerol. Natural organic triglycerides (viz. virgin vegetable oils, recycled cooking oils, and animal fats) are the main sources for biodiesel production. Biodiesel (mono alkyl esters) is the most attractive alternative fuel to diesel, with numerous environmental advantages over petroleum-based fuel. The most practicable method for converting triglycerides to biodiesel with viscosities comparable to diesel fuel is transesterification. Previous research has proven that biodiesel–diesel blends can operate the compression ignition engine without the need for significant modifications. However, the commercialization of biodiesel is still limited due to the high cost of production. In this sense, the transesterification route is a crucial factor in determining the total cost of biodiesel production. Homogenous base-catalyzed transesterification, industrially, is the conventional method to produce biodiesel. ...

The simultaneous esterification and transesterification of Jatropha curcas oil (JCO) was carried out in the presence of Bi2O3 (1–7 wt.%) modified La2O3 catalyst at atmospheric pressure. The catalyst were characterized by X-ray diffraction (XRD), BET surface area, desorption of CO2 (TPD-CO2) and NH3 (TPD-NH3). Under the optimal reaction condition of methanol/oil molar ratio of 15:1, 2 wt.% of catalyst amount and a reaction temperature of 150 C for 4 h, the highest conversion of biodiesel obtained was 93%. This catalyst maintained 87% of FAME conversion after three times of successive reuse.

Dependence on fossil fuels for meeting the growing energy demand is damaging the world’s environment. There is a dire need to look for alternative fuels that are less potent to greenhouse gas emissions. Biofuels offer several advantages with less harmful effects on the environment. Biodiesel is synthesized from the organic wastes produced extensively like edible, non-edible, microbial, and waste oils. This study reviews the feasibility of the state-of-the-art feedstocks for sustainable biodiesel synthesis such as availability, and capacity to cover a significant proportion of fossil fuels. Biodiesel synthesized from oil crops, vegetable oils, and animal fats are the potential renewable carbon-neutral substitute to petroleum fuels. This study concludes that waste oils with higher oil content including waste cooking oil, waste palm oil, and algal oil are the most favorable feedstocks. The comparison of biodiesel production and parametric analysis is done critically, which is necessary...

Diesel engines are preferred over spark ignition counterparts for heavy-duty applications and power generation plants because of their higher efficiency, durability, and productivity. Currently, the research interests have been propelled towards renewable and sustainable diesel fuels such as biodiesel in order to address the environmental and energy security challenges associated with these energy systems. However, the most challenging issue concerning large-scale production of biodiesel is its relatively high cost over fossil-based diesel owing to high feedstock and manufacturing costs. Therefore, cost-effective and eco-friendly biodiesel production technologies should be necessarily developed and continuously improved in order to make this biofuel more competitive vs. its petroleum counterpart. Accordingly, this paper comprehensively reviews biodiesel manufacturing techniques from natural oils and fats using conventional and advanced technologies with an in-depth state-of-the-art focus on the utmost important unit, i.e., transesterification reactor. The effects of the main influential parameters on the transesterification process are first discussed in detail in order to better understand the mechanisms behind each reactor technology. Different transesterification reactors; e.g., tubular/plug-flow reactors, rotating reactors, simultaneous reaction-separation reactors, cavitational reactors, and microwave reactors are then scrutinized from the scientific and practical viewpoints. Merits and limitations of each reactor technology for biodiesel production are highlighted to guide future R&D on this topic. At the end of the paper, the sustainability aspects of biodiesel production are comprehensively discussed by emphasizing on the biorefinery concept utilizing waste-oriented oils.