Milford A. Hanna

Value-added uses for crude glycerol--a byproduct of biodiesel production

Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds.

The effect of mixing on transesterification of beef tallow

Mixing is very important to the transesterification of beef tallow, because melted beef tallow and a sodium hydroxide–methanol solution (NaOH–MeOH) are immiscible. There was no reaction without mixing. When NaOH–MeOH was added to the melted beef tallow in the reactor while stirring, stirring speed was insignificant. Reaction time was the controlling factor in determining the yield of methyl esters. This suggested that the stirring speeds investigated exceeded the threshold requirement of mixing. When NaOH–MeOH was added to the melted beef tallow without stirring, higher stirring speeds or longer stirring times were needed to mix the two phases subsequently. In both cases, once the two phases were mixed and the reaction was started, stirring was no longer needed. Miseks equation was applicable to the former case. The droplet diameter was inversely proportional to the square of the rotation speed. But in the latter case, the droplet diameter was inversely proportional to n1.2. Smaller NaOH–MeOH droplets in melted beef tallow resulted in fast transesterification reaction and stable emulsion.

Alternative diesel fuels from vegetable oils

Abstract This paper reviews the use of vegetable oils and animal fats as diesel fuel. Physical and chemical properties and structure of the vegetable oils are discussed. Fuel preparation by transesterification, pryolysis, dilution, and microemulsion and the effects of these processes on the properties of the fuel and, in turn, their effects on the engines have been reviewed. Each of the processes give improved fuel properties over those of unprocessed vegetable oil. The performance of engines using triglyceride based fuels and their emission characteristics are also presented.

Fuel properties of tallow and soybean oil esters

Fuel properties of beef tallow, soybean oil, their esters, and blends with No. 2 diesel fuel and ethanol were determined. Fuel properties tested were viscosity, specific gravity, API gravity, distillation ranges, calculated cetane index, energy content, flash point, water content, sulfur content, carbon residue, particulate matter, acid value, copper-strip corrosion test, ash content, melting point, cloud point, and pour point. Gas-chromatographic analyses of tallow, soybean oil, and their esters were performed to determine their major constituents. Viscosities of soybean oil and tallow were significantly reduced by esterification. Other fuel properties of the esters and their blends with No. 2 diesel fuel and ethanol were similar to the properties of No. 2 diesel fuel.

Synthesis and Characterization of Starch Acetates with High Substitution

ABSTRACT Acetylation of high-amylose (70%) maize starch to high degree of substitution (DS) was studied by reacting starch with acetic anhydride using 50% aqueous NaOH as the catalyst. DS increased with increasing reaction times and increasing ratios of acetic anhydride to starch. Reaction efficiency (RE) increased with longer reaction times and decreased with increases in the ratios of acetic anhydride to starch for extended reaction times. Increasing the amount of NaOH increased both DS and RE. A series of starch acetates with DS values of 0.57–2.23 were prepared and their crystalline structures, chemical structures, thermal stability, and morphological properties were investigated. After acetylation, and as DS increased from 0.57 to 2.23, the crystalline structures of starch steadily disappeared. The carbonyl groups peak at 1,740 cm-1 appeared in the FTIR spectra. The intensity of this peak increased with a decrease in the peak intensity of the hydroxyl groups at 3,000-3,600 cm-1, indicating that the ...

Steam-air fluidized bed gasification of distillers grains: effects of steam to biomass ratio, equivalence ratio and gasification temperature.

In this study, thermochemical biomass gasification was performed on a bench-scale fluidized-bed gasifier with steam and air as fluidizing and oxidizing agents. Distillers grains, a non-fermentable byproduct of ethanol production, were used as the biomass feedstock for the gasification. The goal was to investigate the effects of furnace temperature, steam to biomass ratio and equivalence ratio on gas composition, carbon conversion efficiency and energy conversion efficiency of the product gas. The experiments were conducted using a 3x3x3 full factorial design with temperatures of 650, 750 and 850 degrees C, steam to biomass ratios of 0, 7.30 and 14.29 and equivalence ratios of 0.07, 0.15 and 0.29. Gasification temperature was found to be the most influential factor. Increasing the temperature resulted in increases in hydrogen and methane contents, carbon conversion and energy efficiencies. Increasing equivalence ratio decreased the hydrogen content but increased carbon conversion and energy efficiencies. The steam to biomass ratio was optimal in the intermediate levels for maximal carbon conversion and energy efficiencies.

Cast Films from Soy Protein Isolates and Fractions

ABSTRACT Glycerol-plasticized soy protein films were cast from alkaline aqueous film-forming solutions of laboratory-prepared 7S, 11S, and soy isolate (LSI) fractions and from commercial soy isolate (CSI). Tensile strength (TS), elongation at break (E), water vapor permeability (WVP), total soluble matter (TSM), protein solubility (PS), and Hunter L, a, and b color values of these films were determined. The 11S films had greater TS than 7S films (P 0.05). The 7S films had higher TSM and PS values than 11S films (P < 0.05). CSI films were significantly darker (lower L value) and more yellow (greater positive b value) than LSI films (P < 0.05).

Experimental studies for levulinic acid production from whole kernel grain sorghum

Levulinic acid has potential as an important basic chemical material. This study proposed a method of making levulinic acid using abundant and low cost whole kernel sorghum grain as the raw material. Flour made from grinding whole kernel sorghum grains was blended with 2%, 5% and 8% aqueous solutions of sulfuric acid. Mixtures were heated to 160 or 200 degrees C in a pressurized reactor. A stepwise heating scheme helped improve the yield of levulinic acid. Levulinic acid yield was determined based on sorghum flour content, as opposed to total sorghum mass. Levulinic acid yield increased as reaction temperature increased. Higher sulfuric acid concentration also significantly increased the levulinic acid yield. However, flour loading had an adverse effect on levulinic acid yield. A maximum yield of 32.6% levulinic acid was achieved at 200 degrees C, 8% sulfuric acid concentration and 10% flour loading. A linear regression model was capable of predicting the levulinic acid yield with respect to effects of reaction temperature, mineral acid concentration and flour loading (R2 = 0.88).

Sodium dodecyl sulfate treatment improves properties of cast films from soy protein isolate

The manufacture of edible/biodegradable films or coatings can potentially add value to soy protein. This study was conducted to determine the effect of sodium dodecyl sulfate (SDS) on selected physical properties of glycerin-plasticized soy protein isolate (SPI) films. Films were cast from heated (70 °C for 20 min), alkaline (pH 10) aqueous solutions of SPI (5 g/100 ml water), glycerin (50% w/w of SPI), and SDS (0, 5, 10, 20, 30, or 40% w/w of SPI). Tensile strength (TS), elongation at break (E), moisture content (MC), total soluble matter (TSM), water vapor permeability (WVP), and color values (L, a, and b) were determined after conditioning film specimens at 25 °C and 50% relative humidity (RH) for 2 days. SDS reduced (P < 0.05) film TS by as much as 43% for films with 40% SDS (6.2 vs. 10.9 MPa for control SPI films). In con trast, film E increased ( P < 0.05) notably with addition of SDS even at 5%. Films with SDS had smaller (P < 0.05) MC and larger (P < 0.05) TSM values than control SPI films. Films contain ing 10% or more SDS had lower WVP values than control SPI films by as much as 50%. In creased yellowness, evidenced by greater (P < 0.05) + b color values, was noted for films with high amounts (20, 30, or 40%) of SDS. Changes in tensile, solubility, and water vapor barrier properties of SPI films due to the addition of SDS were largely attributed to disruption of hy drophobic associations among neighboring protein molecules as the non-polar portions of the SDS molecules attached onto hydrophobic amino acid residues within the film structure. It was demonstrated that adding anionic surfactant SDS to film-forming solutions prior to casting could greatly modify the properties of SPI films. In particular, SDS improved the water vapor barrier ability and the extendibility of SPI films, both desirable attributes when assessing the potential of such films for packaging applications.

Rheological properties of amorphous and semicrystalline polylactic acid polymers

Abstract Corn starch fermentation provides an abundant supply of lactic acid. Polymerization of lactic acid into polylactic acid (PLA) produces a biodegradable thermoplastic polyester with excellent functional properties comparable to many petroleum-based plastics. PLA polymers are made into useful items using thermal processes, such as injection molding and extrusion. Therefore, its rheological properties, especially the shear viscosity ( η ), have important effects on the thermal processes, such as film blowing, paper coating, injection molding, sheet forming and fiber spinning. In this study, viscosities of two types of PLA resins (amorphous and semicrystalline) at 150 and 170°C and at various shear rates (30, 50, 70, 90, 110, 130, and 150 rpm screw speeds) were measured with a tube rheometer on an extruder. The viscosity data was calculated from the pressure profiles and the volume flow rate. Statistical analyses were performed using SAS. The effects of resin type, temperature and shear rate on melt viscosity were determined. Under the same processing conditions, semicrystalline PLA had a higher shear viscosity than amorphous PLA. As the temperature increased, the shear viscosity decreased for both types of PLA. The PLA melt was characterized as a pseudoplastic, non-Newtonian fluid. Power law equations adequately described the behavior of the PLA melts ( r 2 >0.99).