Browsing by Subject "Biodiesel"

Now showing 1 - 4 of 4
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    Biofuel combustion: a single particle approach including new tandem measurements.
    (2011-10) Dutcher, Dabrina D
    The physicochemical properties of aerosol particles are complex. They are often irregular in shape, and can contain complex mixtures of liquids and solids. By measuring multiple properties of a particle, it is possible to describe it more completely than is possible if only one property is evaluated. This is the principle behind the theme of this chapter: tandem aerosol measurements. The Aerosol Time-of-Flight Mass Spectrometer carries out tandem measurements of a particle's vacuum aerodynamic diameter and its composition. I describe here the use of the ATOFMS in series with instruments that measure other properties so as to provide still more information. These additional properties include particle mobility, mass, and "brightness" (i.e., the amount of light that it scatters when illuminated by a laser). In addition, we show that when the ATOFMS is used downstream of tandem differential mobility analyzer systems (TDMA), new information can be gained about species that affect a particle's hygroscopicity (HTDMA) or volatility (VTDMA). These novel instrument combinations yield information regarding the dependence of particle effective density, volatility, and hygroscopicity on particle composition. Additional information is presented about the relationship between particle mobility size and vacuum aerodynamic size for assorted particle types and about the unanticipated difficulties that I encountered when using the ATOFMS for tandem measurements. I discovered that the rotating seals in the aerosol particle mass analyzer (APM) contain compounds that volatilize and react with acidic particles. The ATOFMS is exceedingly sensitive to these reaction products, so much so that it is not possible to obtain meaningful information about the composition of the particles under investigation. This sensitivity may provide a sensitive means, however, to assess the particle acidity.
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    New technologies for the complete rendering and economic conversion of waste oils to biofuels
    (2017-12) Anderson, Erik
    A novel process was developed for the biorefining of floatable wastewater scum and other waste oils from water treatment facilities into biodiesel and other value-added bio-products. To test the scalability and commercial potential of the technology, a 7,000 liter/year pilot-scale system was designed and built. Scum from a waste water treatment facility, located in St. Paul, Mn, was collected and converted into methyl esters (biodiesel) according to the process chemistry. All the incoming and outgoing process streams were sampled, tested, weighed and recorded to calculate both the process efficiency and product quality. Data from the pilot-scale systems operation was compared to laboratory results and the theoretically expected values for each individual unit operation. The product quality was tested using a third-party laboratory and confirmed the biodiesel produced during a single batch process met all of EPA’s test requirements for commercial-grade biodiesel. As a substrate for biodiesel, scum derived oil requires more pretreatment consideration than standard waste oils like used vegetable oil or brown grease. Combining acid hydrolysis and solvent extraction, a free fatty acid and acyl-glycerol rich product was produced from a highly impure source. Free fatty acids (FFA) present were converted to acyl-glycols via a high temperature (238°C) glycerin esterification process known as glycerolysis. The inorganic catalysts zinc aluminum oxide and sodium sulfate was tested during glycerolysis to compare the reaction kinetics of converting FFA to acyl-glycerols. It was concluded that the zinc-based catalyst increased the reaction rate significantly, from a “k” value of 2.57 (uncatalyzed) to 5.63, completing the reaction in 60 minutes, half the time it took the uncatalyzed reaction (120 min). Sodium sulfate’s presence however slowed the reaction, resulting in a “k” value of 1.45, completing the reaction in 180 minutes. Use of the external catalyst Zn-Al2O3 showed the greatest catalytic potential, but also assumes additional costs. In the U.S., the total amount of municipal solid waste is continuously rising each year. Millions of tons of solid waste and scum are produced annually that require safe and environmentally sound disposal. The availability of a zero-cost energy source like municipal waste scum is ideal for several types of renewable energy technologies. However, the way the energy is produced, distributed and valued also contributes to the overall process sustainability. An economic screening method was developed to compare the potential energy and economic value of three waste-to-energy technologies; incineration, anaerobic digestion, and biodiesel. A St. Paul, MN wastewater treatment facility producing 3,175 “wet” kilograms of scum per day was used as a basis of the comparison. After applying all theoretically available subsidies, scum to biodiesel was shown to have the greatest economic potential, valued between $491,949-$610,624/year. The incineration of scum yielded the greatest reclaimed energy potential at 29 billion kilojoules/year. The use of vacuum distillation for biodiesel production has become a reliable post-treatment method for removing multiple impurities, to consistently produce commercial-grade biodiesel. The waste produced from biodiesel distillation, vacuum distillation bottoms (VDB), is a mixture of higher molecular weight methyl esters (84%) and derivatives. Microwave-assisted pyrolysis (MAP) has been researched as a methyl ester recovery process for VDBs leaving vacuum distillation. Two types of MAP processing, dMAP and fMAP, were developed and tested to determine the optimal reaction conditions for producing a biodiesel analogue. The results indicate that after dMAP, 85.9% wt/wt of the VDBs were recovered as a transparent bio-oil then blended back into B100 biodiesel and certified for sale using ASTM D6751. Blending dMAP bio-oil (10% wt/wt) with B100 biodiesel met all certification requirements and demonstrated that MAP processing could be a significant yield improvement technology for any commercial biodiesel producer utilizing vacuum distillation.
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    Study of Oleaginous Fungi Screened from Oil-Rich Plants for Improved Lipid Production
    (2016-11) Yang, Yan
    Biodiesel generated from lipid transesterification can be used as a replacement or blended with for petroleum diesel in any proportion. Current processes to produce biodiesel mostly use plant oil as feedstocks, which keep the costs at high levels and result in a shortage of edible oil in food market. Lipids created via microbial biosynthesis are a potential raw material to replace plant-based oil for biodiesel production. The production of biodiesel from lignocellulosic biomass and other waste materials would have both economic and environmental benefits. This research focused on the screening and identifying novel oleaginous fungal strains with both high lipid content and capability of cellulase enzyme production, the study of the characteristics of selected strain in lipid accumulation process, and the utilization of selected strain in converting lignocellulosic biomass to fungal lipids for biodiesel production. The first step of this research is the screening and identifying fungi from soybean and soil surrounding to soybean plants, and analyzing fungal community of the screened isolates. From two sets of screenings, 33 fungal isolates were obtained from soybean samples collected in August and 17 fungal isolates were obtained from soybean samples collected in October. Meanwhile, the screening from soil surrounding to soybean plant roots obtained 38 fungal isolates. Soybean samples and soil samples showed a great difference in the isolated fungal community, and difference of fungal diversity was also detected from soybean samples collected in August and samples collected in October. Also, different sampling locations had differences in fungal community. These results demonstrated an impact of environment on fungal community, and also indicated a change of plant-associated fungal community through time in soybean samples. For soybean samples, Fusarium and Alternaria were the dominant genera, and other frequently detected genera included Penicillium, Nigrospora, Cercospora and Epicoccum. For soil samples, Trichoderma, Fusarium, Mucor and Talaromyces were most frequently isolated genera. The second step of this research is the bioprospecting of fungal strains isolated from soybean and soil for lipid accumulation to identify strains with high lipid content and cellulase production. Among 33 fungal isolates screened from soybean plant, 13 were oleaginous fungi (lipid content>20% dry biomass weight); among 38 fungal isolates screened from the surrounding soil, 14 were oleaginous fungi. A considerable amount of fungi were identified as oleaginous fungi, and fungi with highest lipid content (>40%) belong to Fusarium genus. One of the strains was selected as the most promising strain was Fusarium equiseti UMN-1 strain. This strain has high lipid content (>56%) and high fatty acid methyl ester (FAME) content (98% in total lipid), also produces cellulase. In addition, it can utilize a wide range of substrates and has promising oil composition for biodiesel production. The F. equiseti UMN-1 strain offers great potential for biodiesel production by directly utilizing lignocellulosic biomass as feedstocks, and was used in the following studies. The third step of this research is the investigation on the characteristic of F. equiseti UMN-1 strain and optimization of cultivation conditions for higher lipid production. Characteristic study of this strain determined the optimal temperature as 27 °C and agitation speed as 150 rpm. The best C:N ratio for lipid accumulation was 80, strong light during cultivation was not suggested, and 6 to 8 day’s culture was sufficient for this strain to reach a high level of lipid production. This fungal strain obtained higher lipid production when using fructose and mannose as carbon source, but it also can grow well on a variety of carbon sources. Most suitable nitrogen source for lipid production was the combination of (NH4)2SO4 and yeast extract. According to the response surface analyses results of the central composite design (CCD), the optimal growth condition for flask culture was 23.7 °C, 37.39 g/L glucose and 0.236 g/L nitrogen (N). The maximum lipid production was predicted as 3.91 g/L, and 3.89 g/L lipid production was verified from flask culture under the optimized conditions. The fourth step of research is to explore the application of F. equiseti UMN-1 strain in lignocellulosic lipid production and study different fermentation process to improve lipid accumulation. When directly using lignocellulosic biomass for lipid production, this strain achieved a lipid yield of 59.1±2.7 mg/g from soybean hulls and 61.1±2.6 mg/g from corn stover through solid state fermentation with 90% moisture content. Application of pretreatment and cellulase hydrolysis further increased the lipid yield to 69.2±5.0 mg/g from corn stover in integrated fermentation. F. equiseti UMN-1 strain was shown to have the capability of lipid accumulation from a variety of materials, and it could be a potential candidate as a lipid source in the production of lignocellulosic biodiesel.