Due to the finite stock of fossil fuels and its negative impact on the environment, many countries across the world are now leaning toward renewable sources energies like solar energy, wind energy, biofuel, hydropower, geothermal and ocean energy to ensure energy for the countries development security. Biodiesel is one kind of biofuel that is renewable, biodegradable and has similar properties of fossil diesel fuel. The aim of this paper is to provide the substantial information on biodiesel to the researchers, engineers and policy makers. To achieve the goal, this paper summarizes the information on biofuel development, feedstocks around the world, oil extraction technic, biodiesel production processes. Furthermore, this paper will also discuss the advantages of biodiesel compared to fossil fuel. Finally, the combustion behavior of biodiesel in an internal combustion engine is discussed and it will help the researchers and policy maker and manufacturer. To determine the future and goal of automotive technology the study found that, feedstock selection for biodiesel production is very important as it associates 75% production cost. Moreover, the test of fuel properties is very important before using in the engine which depends on the type of feedstocks, origin country, and production process. Most of the researchers reported that the use of biodiesel in diesel engine reduces engine power slightly but reduces the harmful emission significantly. Finally, the study concludes that biodiesel has the potential to be used as a diesel fuel substitute in diesel engines to solve the energy and environment crisis.

Production, characterization and performance of biodiesel as an alternative fuel in diesel engines – A review

Biofuels have grabbed the attention of engine researchers ever since the oil-crisis and escalating costs of petro-chemicals cropped up in the ׳70s. Ethanol and methanol were the most widely researched alcohols in IC engines. However, the last decade has witnessed significant amount of research in higher alcohols due to the development of modern fermentation processes using engineered micro-organisms that improved yield. Higher alcohols are attractive second/third generation biofuels that can be produced from sugary, starchy and ligno-cellulosic biomass feedstocks using sustainable pathways. The present work reviews the current literature concerning the effects of using higher alcohols ranging from 3-carbon propanol to 20-carbon phytol on combustion, performance and emission characteristics of a wide range of diesel engines under various test conditions. The literature is abound with evidence that higher alcohols reduce carcinogenic particulate emissions that are prevalent in diesel engines. NOx emissions either increased or decreased based on the domination of either cetane number or heat of evaporation. Brake specific fuel consumption (BSFC) of the engine usually suffered due to low energy content of alcohols. A notable feature is that the combination of higher alcohols (like butanol or pentanol), high exhaust gas recirculation (EGR) rates and late injection timing enabled low temperature combustion (LTC) in diesel engines that can simultaneously reduce smoke and NOx emissions with improved engine efficiency. It can be concluded that higher alcohols reduce smoke emissions with their fuel-borne oxygen; enhance air/fuel mixing by offering long ignition delay and eventually replace fossil diesel (partially or wholly) to enable a clean and efficient combustion in compression-ignition engines. The chief thrust areas include developing mutant strains with higher yield, higher tolerance to toxic inhibition and low-cost substrates for fermentation. Further work is required in stipulating optimum blend-fuel characteristics and ensuring the long-term durability of the engines using these fuels.

Use of higher alcohol biofuels in diesel engines: A review

The increasing energy demand, surging oil prices, depleting oil reserves and environmental pollution problems associated with the use of fossil fuels have sparked renewed interest to find out clean alternative fuels. Alcohols such as methanol, ethanol and butanol are competitive alternative fuels due to their liquid nature, high oxygen contents, high octane number and their production from renewable biomass. In this review, the fuel properties of these alcohols are compared with conventional gasoline and diesel fuel. The comparison of fuel properties represents that butanol has the potential to overcome the problems associated with the use of methanol and ethanol. Progresses of their production from different sources are also introduced. Further, several techniques such as alcohol–diesel fuel blends and alcohol–diesel fuel emulsions are discussed, especially for lower alcohols, in order to use them in diesel engines. The effects of diesel–alcohol blends on the combustion, performance and emissions of diesel engines are also analyzed. It is examined that blending of alcohols, along with some CN improver, to diesel fuels can reduce diesel engine emissions without adverse impacts on the performance of diesel engines. These studies also reveal that butanol is a better alternative for diesel fuel due to its superior fuel properties and miscibility with diesel fuel than those of methanol and ethanol. Finally, some critical conclusions and future research directions are highlighted.

Advances in diesel–alcohol blends and their effects on the performance and emissions of diesel engines

The effect of nano-additives in diesel-biodiesel fuel blends: A comprehensive review on stability, engine performance and emission characteristics

Combined effect of influence of nano additives, combustion chamber geometry and injection timing in a DI diesel engine fuelled with ternary (diesel-biodiesel-ethanol) blends

The synthesis of tailored and highly engineered multifunctional pharmaceutical nanocarriers is an emerging field of study in drug delivery applications. They have a high surface-area-to-volume ratio, aiding the targeted drug’s biodistribution and pharmacokinetic properties. Therefore, the characterization of nanocarriers is critical for understanding their physicochemical properties, which significantly impact their molecular and systemic functioning. To achieve specific goals, particle size, surface characteristics, and drug release properties of nanocarriers must be managed. This mini review provides an overview of the applications of non-destructive testing techniques (NDTT) to reveal the characteristics of nanocarriers, considering their surface charge, porosity, size, morphology, and crystalline organization. The compositional and microstructural characterization of nanocarriers through NDTT, such as dynamic light scattering, X-ray diffraction, confocal laser scanning microscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, atomic force microscopy, and nuclear magnetic resonance spectroscopy, have been comprehensively reviewed. Furthermore, NDTT is only used to characterize physicochemical parameters related to the physiological performance of nanocarriers but does not account for nanocarrier toxicity. Hence, it is highly recommended that in the future, NDTT be developed to assess the toxicity of nanocarriers. In addition, by developing more advanced, effective, and precise techniques, such as machine vision techniques using artificial intelligence, the future of using NDTT for nanocarrier characterization will improve the evaluation of internal quality parameters.

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Application of Non-Destructive Testing Techniques (NDTT) to Characterize Nanocarriers Used for Drug Delivery: A Mini Review

The aim of experimental investigation is to analyze the change in performance characteristics when Partially Stabilized Zirconia (PSZ) was used as a thermal barrier coating in the combustion chamber, with emulsified fuel. Sorbitan mono elate (span 80) and PEG 20 sorbitan monooleate (tween 80) were used as the surfactants to form an emulsified fuel with diesel and water. Diesel, water and surfactants were taken in a flask; continuous stirring was done at a speed of 1000 rpm. The stability of the emulsified fuel has been checked for 8 hours for separation. It was observed that a remarkable improvement in brake thermal efficiency and specific fuel consumption. The results of the experiment proved that PSZ would be used as a performance improver as it retains the combustion temperature and increases the efficiency to a significant level.

https://iopscience.iop.org/article/10.1088/1757-899X/263/6/062051/pdf

Effect of partially stabilized zirconia (Zr2O) in improving the efficiency of emulsified fuel

Hydrodynamic Studies of Bubble Absorber Withswirl Entry of Refrigerant

Performance enhancement of horizontal tube falling film evaporators using thin metal foam was studied. A copper foam was brazed over the outer surface of a copper horizontal tube and used in the falling film evaporator of a desalination system. It was observed that the distillate production and heat transfer rate was enhanced by more than twice with the modified tube. Effect of feed rate, feed temperature, and subcooling on distillate production was studied for the copper foam-wrapped heat exchanger tube evaporator. A metal foam-wrapped heat exchanger tube was also used to study the effect of scale formation. The effects of temperature, flow rate, and seawater turbidity on scale formation was studied. Total scale deposit weight was observed after every 16 h of operation for a total run time of 128 h. It was observed that scale formation reduces with an increase in flow rate and increases with seawater temperature. It was also observed that scale formation is lower when the system is operated with seawater of low turbidity. The heat transfer enhancement surface promotes scale formation due to the increase in metal surface area in contact with seawater as in the copper foam-wrapped tube. Energy-dispersive X-ray spectroscopy and scanning electron microscopy were applied to investigate the mineralogy and microstructure of the deposits. 

Heat transfer enhancement and scale formation experimental studies in falling film evaporator using copper metal foam

The emphasis to conserve petroleum-based fuels has provided the motivation for several studies on the development and testing of alternate fuels in diesel engine. This paper investigates the effect of using diesohol (ethanol-diesel blend) as a fuel in a DI diesel engine. In this investigation, two different composition of diesohol were selected for examination. One was 5% ethanol and 95% diesel and another one was 10% ethanol and 90% diesel. In order to avoid phase separation of diesohol, the blend was preheated to 35 o C. The result of pure petroleum diesel fuel operation was taken as a base line reading to examine the effectiveness of the two diesohol compositions. The result shows that the use of diesohol, keep the combustion temperature low. It also resulted in reduction in NOX and smoke emission. This undoubtedly proved that diesohol can be used in diesel engine without any major modification in the engine.

K. Annamalai

Papers

Application of Non-Destructive Testing Techniques (NDTT) to Characterize Nanocarriers Used for Drug Delivery: A Mini Review

Effect of partially stabilized zirconia (Zr2O) in improving the efficiency of emulsified fuel

Hydrodynamic Studies of Bubble Absorber Withswirl Entry of Refrigerant

Heat transfer enhancement and scale formation experimental studies in falling film evaporator using copper metal foam

A renewable alternative fuel for diesel engines - diesohol