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A User’s Guide

The demand for petroleum has risen rapidly due to increasing industrialization and modernization of the world. This economic development has led to a huge demand for energy, where the major part of that energy is derived from fossil sources such as petroleum, coal and natural gas. However, the limited reserve of fossil fuel has drawn the attention of many researchers to look for alternative fuels which can be produced from renewable feedstock. Biodiesel has become more attractive because of its environmental benefits and it is obtained from renewable resources. There are four primary methods to make biodiesel: blending, microemulsion, pyrolysis and transesterification. The most commonly used method is the transesterification of triglycerides (vegetable oil and animal fats) with alcohol in the presence of a catalyst. There is a growing interest in using Jatropha curcas L. oil as the feedstock for biodiesel production because it is non-edible and thus does not compromise the edible oils, which are mainly used for food consumption. Non-edible oils are not suitable for human consumption because of the presence of toxic components. Further, J. curcas L. seed has a high content of oil and the biodiesel produced has similar properties to that of petroleum-based diesel. In this paper, an attempt has been made to review the different approaches and techniques used to generate biodiesel from Jatropha curcas oil. The main factors affecting the biodiesel yield, for example the molar ratio of alcohol to oil, catalyst concentration, reaction temperature and reaction time are discussed. Lastly, the environmental considerations and economic aspects of biodiesel are also addressed.

/pdf/a-review-of-biodiesel-production-from-jatropha-curcas-l-oil-198dc8kg92.pdf

A review of biodiesel production from Jatropha curcas L. oil

https://web.ics.purdue.edu/~lqiao/Publications_files/Combustion%20characteristics%20of%20fuel%20droplets%20with%20addition%20of%20nano%20and%20micron-sized%20aluminum%20particles.pdf

Combustion characteristics of fuel droplets with addition of nano and micron-sized aluminum particles

A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.

/pdf/wide-range-modeling-study-of-dimethyl-ether-oxidation-pnag57ojwu.pdf

Wide range modeling study of dimethyl ether oxidation

Modelling of fuel droplet heating and evaporation: Recent results and unsolved problems

/pdf/smoldering-combustion-of-biomass-particles-4unsp0934a.pdf

Smoldering combustion of biomass particles.

A numerical study of steady burning of spherical ethanol particles in a spray environment is presented. A spray environment is modeled as a high temperature oxidizer stream where the major products of combustion such as carbon dioxide and water vapor will be present along with reduced amounts of oxygen and nitrogen. The numerical model, which employs variable thermophysical properties, a global single-step reaction mechanism, and an optically thin radiation model, has been first validated against published experimental results for quasi-steady combustion of spherical ethanol particles. The validated model has been employed to predict the burning behavior of the ethanol particle in high temperature modified oxidizer environment. Results show that based on the amount of oxygen present in the oxidizer the burning rate constant is affected. The ambient temperature affects the burning rate constant only after a sufficient decrease in the oxygen content occurs. In pure air stream, ambient temperature variation does not affect the evaporation constant. Results in terms of burning rates, maximum temperature around the particle, and the evaporation rate constants are presented for all the cases. The variation of normalized Damkohler number is also presented to show the cases where combustion or pure evaporation would occur.

/pdf/numerical-modeling-of-steady-burning-characteristics-of-3oo5lm8wkb.pdf

Numerical Modeling of Steady Burning Characteristics of Spherical Ethanol Particles in a Spray Environment

Composition Effects on Thermo-Physical Properties and Evaporation of Suspended Droplets of Biodiesel Fuels

Oil spill cleanup in Arctic is usually done by in-situ burning. The fuel oil will have a very low initial temperature as well as cold boundaries. This study focuses on the variation of the mass burning rate of the fuel with varying initial temperatures of the fuel, which is kept in a metal bowl surrounded by ice. Kerosene is chosen as the fuel. The bowl diameters have been varied from 30 mm to around 50 mm. The fuel bowl is kept surrounded in an ice bath and is ignited after it attains a particular temperature. The initial temperature of the fuel is varied from 4 o C to 16 o C. Experiments are carried out for 5 minutes after which the flame is quenched. The results show that with increase in the initial temperature of the fuel the mass burning rate also increases. The mass burning rate also increases as the fuel bowl diameter increases. The surface temperature of the fuel, just after quenching, increases with an increase in the initial temperature of the fuel. The ignition time of the fuel is reduced with increase in initial temperature of the fuel and with increase in bowl diameter. The flame height variations are also recorded.

Vasudevan Raghavan

Papers

Smoldering combustion of biomass particles.

Numerical Modeling of Steady Burning Characteristics of Spherical Ethanol Particles in a Spray Environment

Composition Effects on Thermo-Physical Properties and Evaporation of Suspended Droplets of Biodiesel Fuels

Experimental Study of Initial Fuel Temperature on the Burning Rates of Kerosene Pools in Cold Environment

Experimental study of burning of methanol fed porous spheres in grid generated turbulent field