John W. Goodrum

Volatility and boiling points of biodiesel from vegetable oils and tallow

Abstract Quality control of fuel-related properties of Biodiesel, such as volatility, is needed to obtain consistent engine performance by fuel users. The vapor pressures and boiling points of selected methyl esters and vegetable oils are proposed as quality control metrics for Biodiesel. This type of data was obtained by a rapid new method using thermogravimetric analysis (TGA). One atmosphere boiling points (bps) and temperature-dependent vapor pressures from 1 atm down to 5.332 kPa (40 mmHg ) were measured for methyl and ethyl esters of rapeseed oil, canola oil, soybean oil, and tallow. Boiling points (1 atm ) ranged from 340°C to 375°C. Methyl and ethyl esters of a given oil differ by ca. 5°C in bps. These results are discussed in terms of the fatty acid composition of the esters and oils. Calibrations showed that the TGA/laser orifice capsule method gave accuracy of ±5%.

DSC studies to evaluate the impact of bio-oil on cold flow properties and oxidation stability of bio-diesel.

This paper describes the use of Differential Scanning Calorimetry (DSC) to evaluate the impact of varying mix ratios of bio-oil (pyrolysis oil) and bio-diesel on the oxidation stability and on some cold flow properties of resulting blends. The bio-oils employed were produced from the semi-continuous Auger pyrolysis of pine pellets and the batch pyrolysis of pine chips. The bio-diesel studied was obtained from poultry fat. The conditions used to prepare the bio-oil/bio-diesel blends as well as some of the fuel properties of these blends are reported. The experimental results suggest that the addition of bio-oil improves the oxidation stability of the resulting blends and modifies the crystallization behavior of unsaturated compounds. Upon the addition of bio-oil an increase in the oxidation onset temperature, as determined by DSC, was observed. The increase in bio-diesel oxidation stability is likely to be due to the presence of hindered phenols abundant in bio-oils. A relatively small reduction in DSC characteristic temperatures which are associated with cold flow properties was also observed but can likely be explained by a dilution effect.

Physical properties of low molecular weight triglycerides for the development of bio-diesel fuel models

To aid the improvement of fuel properties of oils, basic physical and combustion-related properties of low molecular weight triglycerides are described. These properties include density, viscosity, heat capacity, surface tension and vapor pressure. Fuel injection atomization factors were determined for these triglycerides. Properties of tributyrin (C4:0), tricaproin (C6:0), tricaprylin (C8:0) and tricaprin (C10:0) indicate that these triglycerides are potential components in future diesel fuels derived from plant oils.

Rheological characterization of animal fats and their mixtures with #2 fuel oil

To aid in the development of biomass fuels based on waste animal fats, as of yet unpublished rheological properties of these fats and their mixtures with petroleum-based fuels are needed. The viscosities and densities of beef tallow, choice white pork fat, poultry fat and yellow grease were experimentally determined to examine their potential use as fuel substitutes or additives. The viscosities of 30% mixtures of these fats with #2 fuel oil fuel were also examined. Dynamic viscosities of these agricultural oils were measured for shear rates of 0.65– at temperatures between 54.4°C and 85°C. The resulting measurements were fitted to a power law model to obtain values for the consistency coefficient and the flow behavior index. These results indicated pseudoplastic flow behavior for all products, with increasingly Newtonian behavior at higher temperatures and shear rates. The mixtures of these fats with fuel oil exhibited even more encouraging rheological properties very near those of pure fuel oil.

Fuel properties of oil from genetically altered Cuphea viscosissima

Abstract A genetically altered plant strain ( Cuphea viscosissima VS-320) was identified which produces an oil with elevated levels of medium- and short-chain triglycerides. Previous studies have suggested that such an oil may be appropriate for use as a substitute for diesel fuel without chemical conversion of component triglycerides to methyl esters. This oil is also of interest for other industrial applications. This paper discusses the oil composition of C. viscosissima VS-320 and presents the analysis of several important alternative fuel screening properties of this oil: dynamic viscosity for shear rates of 1.617–64.69 s − 1 at temperatures of 25–80°C, boiling point at atmospheric pressure, temperature dependence of vapor pressure (from 40 to 760 mmHg for the 300–400°C temperature range), and heat of vaporization (Δ H v ). These properties have been established as indicators of fuel performance and can be used for initial screening of possible diesel fuel substitutes. These properties are compared to those of diesel, biodiesel, and vegetable oils. Analysis of these properties suggests that further genetic development of this plant as a source of diesel fuel is warranted.

Peanut Oil Extraction with SC-CO2: Solubility and Kinetic Functions

ABSTRACT VARIOUS factors affecting SC-CO2 peanut oil extraction were examined. Pressure, temperature, particle size, moisture, and flow rate effects in a vertical extractor were evaluated using a half-factorial design. The effect of temperature and pressure was studied further for temperatures of 25 to 95°C and pressures of 140 to 550 bar. At 25°C and 550 bar, the particle size dependence of both the initial extraction rate and the overall oil yield was studied for particle size of 0.864 to 4.75 mm.

Rapid thermogravimetric measurements of boiling points and vapor pressure of saturated medium- and long-chain triglycerides

In developing compositional models for biomass-based diesel fuel extenders, volatility properties of medium- and long-chain saturated triglycerides are essential to predict the impact of low levels of these compounds in mixtures with short-chain triglycerides. A thermogravimetric analysis (TGA) method for rapid measurement of boiling points and vapor pressure was used to obtain data for four pure medium- and long-chain triglycerides. Normal boiling points at 1 atm and the temperature dependence of vapor pressure from 760 mm down to 25 mm Hg were obtained for trilaurin (C12:0), trimyristin (C14:0), tripalmitin (C16:0), and tristearin (C18:0). The data showed good agreement with the Clausius-Clapeyron model for temperature dependence of vapor pressure up to 1 atm pressure. The results of this study were consistent with those obtained using differential scanning calorimetry (DSC) and with data previously reported for reduced pressure.

Density and viscosity of low-molecular weight triglycerides and their mixtures

The viscosities of tributyrin (C4∶0) and binary mixtures of this triglyceride with a diesel fuel, tricaproin (C6∶0), and tricaprylin (C8∶0) were determined for the temperature range −5 to 85°C and for shear rates of 1.62–64.7 s−1. The resulting dynamic viscosities were fit to a power law model to obtain values for the consistency coefficient and the flow behavior index. These results indicated slightly pseudoplastic flow behavior (indices ranged from 0.94 to 0.99) for tributyrin and its mixtures. The calculated consistency coefficients for tributyrin and those previously obtained for tricaproin, tricaprylin and tricaprin were fit by a least-squares method to the three-parameter Vogel model to account for the effect of temperature. An ideal solution relationship and the Kendall-Monroe model were used to predict the density and consistency coefficients, respectively, for binary and quaternary mixtures of these low-molecular weight triglycerides.

RAPID SCREENING OF BIOLOGICALLY MODIFIED VEGETABLE OILS FOR FUEL PERFORMANCE

A process for the rapid screening of alternative diesel fuel performance was applied to analogues of genetically modified vegetable oils and a mixture with no. 2 diesel fuel. The oils examined contained 60 to 80% of low molecular weight, short-chain, saturated triglycerides compared to the 1 to 2% found in traditional vegetable oils. These oils have relatively low viscosity that is predicted to enhance their performance as alternative diesel fuels. The screening process utilizes an engine “torque test” sequence that accelerates the tendency of diesel fuels to coke fuel injectors, a key indicator of fuel performance. The results of the tests were evaluated using a computer vision system for the rapid quantification of injector coking. The results of the screen were compared to those using no. 2 diesel fuel as a baseline. Coke deposition from the modified vegetable oil analogues was not found to be significantly different than deposition from diesel fuel. Suggestions are made to guide further modification of vegetable oil biosynthesis for the production of alternative diesel fuel.

Expeller optimization for peanut oil production

ABSTRACT THE operating conditions of a small expeller for maximum expression of oil from U.S. runner type peanuts were determined by response surface analysis. The peanut moisture content, temperature, period of preheating, and the pressure applied were interactive factors that influenced the oil expression when the pressure of expression was kept at a maximum. Functional relationships between these factors and the meal oil content were established from experimental data. The maximum oil expression achieved was 92%.