Production of biodiesel from waste fish fat through ultrasound-assisted transesterification using petro-diesel as cosolvent and optimization of process parameters using response surface methodology.

Biodiesel is a highly promising and viable alternative to fossil-based diesel that also addresses the urgent need for effective waste management. It can be synthesized by the chemical modification of triglycerides sourced from vegetable origin, animal fat, or algal oil. The transesterification reaction is the preferred method of producing biodiesel. However, the non-miscibility of alcohol and oil layer causes excessive utilization of alcohol, catalyst, and a substantial reacting time and temperature. In the current investigation, transesterification of waste fish oil was performed with petro-diesel as cosolvent, under the influence of ultrasound energy. The combination of both techniques is a unique and efficient way to minimize the mass transfer limitations considerably and hence reduces the parameters of the reaction. It is also a sincere effort to comply with the principles of green chemistry. The optimum reaction conditions were obtained using response surface methodology (RSM) that were as follows: molar ratio of methanol to oil 9.09:1, catalyst concentration of 0.97 wt%, cosolvent concentration of 29.1 wt%, temperature 60.1℃, and a reacting time 30 min. Under these listed conditions, 98.1% biodiesel was achievable, which was in close agreement with the expected result. In addition, the cosolvent removal step from the crude biodiesel was also eliminated as it could be employed as a blended fuel in CI engines.

Effect of hydrogen addition on performance, emission, and combustion characteristics of Deccan hemp oil and its methyl ester-fuelled CI engine.

A vegetable oil-fueled diesel engine operation is characterized by low brake thermal efficiency and relatively high smoke emission. Conversion of vegetable oil to biodiesel results in slight improvement in efficiency and smoke emission, but the values are not comparable with diesel. In this work, a single-cylinder diesel engine's performance is evaluated by inducting hydrogen in small quantities in the intake manifold along with Deccan hemp oil (DHO) and its methyl ester (DHOME) as the pilot fuel. The tests were conducted at part-load and full-load conditions at an engine speed of 1500 rpm. Results indicate an increase in brake thermal efficiency from 29.7 to 32.6% and from 27.3 to 29.6% at full load with hydrogen-induced DHOME and DHO engine operation. Unburned-hydrocarbon emissions, carbon monoxide emission, and smoke emission reduced for both the fuels. However, NOx levels increased for the two fuels because hydrogen induction causes high combustion rates and high temperature in the combustion chamber. Hydrogen induction leads to high premixed combustion resulting in high peak pressures.

The potential impact of unsaturation degree of the biodiesels obtained from beverage and food processing biomass streams on the performance, combustion and emission characteristics in a single-cylinder CI engine.

The purpose of this study is to experimentally investigate the effect of unsaturation of the biodiesels obtained from grapeseed oil, wheat germ oil and coconut oil (reference fuel) for compression ignition (CI) engine application. Fatty acid profile analysis and physio-chemical properties were determined by standard test procedures. Engine testing was carried out in a 5.2-kW single-cylinder CI engine and the combustion, performance and emission characteristics were analysed. The effect of fuel property variation and the combustion reaction kinetics due to unsaturation difference have been discussed. The maximum brake thermal efficiency at full load for diesel was found to be 32.3% followed by 31.3%, 30.2% and 27.4 %, respectively, for coconut biodiesel (CBD), grapeseed biodiesel (GSBD) and wheat germ biodiesel (WGBD). Maximum heat release rate as observed for diesel, CBD, GSBD and WGBD are 63.2 J/°CA 60.7 J/°CA and 59 J/°CA and 43.4 J/°CA respectively. The brake-specific NO emission at full load is higher for CBD followed by GSBD, WGBD and diesel having values of 9.23 g/kWh, 8.91 g/kWh, 8.21 g/kWh and 7.6 g/kWh respectively. Conversely, the smoke emission is lower for CBD compared to the other tested fuels.

NOx-smoke trade-off characteristics of minor vegetable oil blends synergy with oxygenate in a commercial CI engine.

The present study investigates the effect of blending oxygenate namely diethylene glycol dimethyl ether (diglyme) with minor vegetable oil namely rubber seed oil (RSO), babassu oil (BSO), and their blends in various proportions (R75B25, R50B50, and R25B75) on NOx-smoke trade-off and other engine characteristics. The tests were conducted on a commercial twin cylinder compression-ignition (CI) engine commonly used in tractors. The potential of the blends with diglyme is assessed based on performance, emission, and combustion characteristics of the engine at different load conditions. The tests were conducted at a constant speed of 1500 rpm maintaining the original injection timing and pressure. Compared to diesel, RSO, and BSO, and their blends exhibited inferior combustion due to poor physical properties like high viscosity and density. This resulted in a lower brake thermal efficiency with increase in HC, CO, and smoke emissions compared to diesel at all the load conditions. The augmented effect is observed with increase in BSO proportion for the blends and neat BSO. The poor combustion of minor vegetable oil and its blends lead to lower NOx emission as a result of lower in-cylinder temperature. To improve the performance and NOx-smoke trade-off, diglyme (DGM) was added with all the test fuels with the optimum share of 20% (by volume). Addition of DGM, increased brake thermal efficiency by 2-7% for all the test fuels due to improved combustion as a result of additional fuel bound oxygen in DGM and improved fuel blend properties. DGM addition reduced smoke, HC, and CO emission drastically with a slight increase in NOx emission compared to minor vegetable oil blends. The study shows that addition of DGM showed a promising note in NOx-smoke trade-off without affecting the other engine parameters.

Effect of lower and higher alcohol fuel synergies in biofuel blends and exhaust treatment system on emissions from CI engine.

The present study deals with performance, emission and combustion studies in a single cylinder CI engine with lower and higher alcohol fuel synergies with biofuel blends and exhaust treatment system. Karanja oil methyl ester (KOME), widely available biofuel in India, and orange oil (ORG), a low carbon biofuel, were taken for this study, and equal volume blend was prepared for testing. Methanol (M) and n-pentanol (P) was taken as lower and higher alcohol and blended 20% by volume with KOME-ORG blend. Activated carbon-based exhaust treatment indigenous system was designed and tested with KOME-ORG + M20 and KOME-ORG + P20 blend. The tests were carried out at various load conditions at a constant speed of 1500 rpm. The study revealed that considering performance, emission and combustion studies, KOME-ORG + M20 + activated carbon are found optimum in reducing NO, smoke and CO2 emission. Compared to KOME, for KOME-ORG + M20 + activated carbon, NO emission is reduced from 10.25 to 7.85 g/kWh, the smoke emission is reduced from 49.4 to 28.9%, and CO2 emission is reduced from 1098.84 to 580.68 g/kWh. However, with exhaust treatment system, an increase in HC and CO emissions and reduced thermal efficiency is observed due to backpressure effects.