Design and Analysis of Flexible Biodiesel Processes with Multiple Feedstocks

With the growing interest in converting a wide variety of biomass-based feedstocks to biofuels, there is a need to develop effective procedures for the design and optimization of multi-feedstock biorefineries. The unifying goal of this work is the development of systematic methodologies and procedures for designing flexible multifeedstock biorefineries. This work addresses four problems that constitute building blocks towards achieving the unifying goal of the dissertation. The first problem addresses the design and techno-economic analysis of an integrated system for the production of biodiesel from algal oil. With the sequestration of carbon dioxide from power plant flue gases, algae growth and processing has the potential to reduce greenhouse gas emissions. Algae are a non-food oil feedstock source and various pathways and technologies for obtaining algal oil were investigated. Detailed economic and sensitivity analysis reveal specific scenarios that lead to profitability of algal oil as an alternative feedstock. In the second problem, a new safety metric is introduced and utilized in process design and selection. A case study was solved to assess the potential of producing biodiesel from sewage sludge. The entire process was evaluated based on multiple criteria including cost, technology and safety. The third problem is concerned with incorporating flexibility in the design phase of the development of multi-feedstock biofuel production processes. A mathematical formulation is developed for determining the optimal flexible design for a biorefinery that is to accommodate the use of multiple feedstocks. Various objective functions may be utilized for the flexible plant depending on the purpose of the flexibility analysis and a case study is presented to demonstrate one such objective function. Finally, the development of a systematic procedure for incorporating flexibility and heat integration in the design phase of a flexible feedstock production process is introduced for the fourth problem. A mathematical formulation is developed for use in determining the heat exchange network design. By incorporating the feedstock scenarios under investigation, a mixed integer linear program is generated and a flexible heat exchange network scheme can be developed. The solution provides for a network that can accommodate the heating and cooling demands of the various scenarios while meeting minimum utility targets

Foodstuffs And Cancer: Analysis Of Radionuclides And Its Radiation Levels In Common Ghanaian Maize.

By gamma spectroscopic measurement, content of natural and anthropogenic radionuclides and their activity levels were determined in selected common Ghanaian maize. The purpose was to establish whether these levels and subsequently their annual effective doses from the intake of these radionuclides were within the internationally acceptable limits. Six different maize varieties were collected, processed and data on each sample analyzed using a High Purity Germanium Detector. The activity levels and annual effective doses were calculated for the samples. The most significant radionuclides obtained from the analysis were; Potassium (40K), Uranium (238U), Caesium (134Cs), and Thorium (232Th). The average annual effective doses obtained from this study were 0.0039 mSv and 0.0012 mSv for dried and ashed samples respectively. This study concluded that the radionuclide activities and the annual effective doses were within acceptable standard levels and hence these Ghanaian maize varieties suitable for human consumption

Investigation of the Impact of Mycogenic Titanium and Selenium Nanoparticles on Fusarium Wilt Infection of Tomato Plant

We applied biosynthesized titanium and selenium nanoparticles, prepared using a fungal water extract of Trichoderma harzianum (T. harzianum), to eradicate tomota wilt infection. Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy Dispersive X-Ray analysis, and Transmission electron microscopy/X-ray diffraction (TEM/XRD) techniques were used to characterize the spherical metal nanoparticles, whose diameters were 16.0 nm for selenium nanoparticles (SeNPs) and 50.0 nm for titanium nanoparticles (TiNPs). This confirmed the efficient biosynthesis of the nanoparticles. Under greenhouse conditions, the effectiveness of TiNPs and SeNPs produced by nonpathogenic fungi (T. harzianum) against the pathogen responsible for the tomato wilt disease, Fusarium oxysporum (F. oxysporum), was studied. Based on the results, the most efficient method for combating the pathogen that causes tomato wilt was used in open fields, whereas pot studies were conducted in greenhouse conditions. All tested treatments considerably lowered tomato plant wilt disease in both the greenhouse and the open field. The disease severity was reduced by 20.4% using TiNPs at high concentrations of 150 ppm and by 41.5% using SeNPs. Compared to conventional antibiotics, the antibacterial activity assessment of the biosynthesized TiNPs and SeNPs revealed a significant effect versus pathogenic bacteria and fungi, with a negligible influence on the examined human and animal microflora. The findings showed that biosynthesized TiNPs and SeNPs can be applied to suppress the plant pathogen F. oxysporum in a way that is safe for the microflora of humans and animals. This is the first instance where the nanocidal activity of biological TiNPs and SeNPs has been used against the pathogen that causes tomato wilt

A Study on Amorphous Silicon Electronic Portal Imaging Device (A-Si EPID) Response to Delivered Radiation Doses

The use of amorphous silicon flat panel-type electronic portal imaging device (a-Si EPID) as dosimeters in radiotherapy has seen gradual increase in recent times. This research study has assessed dosimetric response of a-Si EPID (Elekta iViewGT) with respect to photon beam qualities on Elekta Synergy Platform linac. Images acquired under reference conditions of 10×10 cm² open field with the a-Si EPID at source to EPID distance (SED) of 159 cm and varying dose of 1-3 Gy in polymethyl methacrylate (PMMA) solid water phantom slabs were used. The experiment was repeated with Farmer-type PTW ionization chamber (IBA 30010) in position and measurement taken at 10 cm in the solid water phantom. Set up conditions for EPID and IC remained same throughout the study. The study observed similar and proportional increases in EPID and IC signals with increasing dose. Maximum deviation of 7.2 % was recorded between EPID and IC measurements. Outcome of the study demonstrates that the a-Si EPID is appropriate for dosimetric verification purposes on the Elekta linac. Comprehensive evaluation of dosimetric properties of EPIDs is thus necessary to ensure reliability in dose measurements on different linac systems

ESolvent-free, enzyme-catalyzed biodiesel production from mango, neem, and shea oils via response surface methodology

Mango, neem and shea kernels produce non-conventional oils whose potentials are not fully exploited. To give an added value to these oils, they were transesterified into biodiesel in a solvent-free system using immobilized enzyme lipozyme from Mucor miehei. The Doehlert experimental design was used to evaluate the methyl ester (ME) yields as influenced by enzyme concentration—EC, temperature—T, added water content—AWC, and reaction time—RT. Biodiesel yields were quantified by (1)H NMR spectroscopy and subsequently modeled by a second order polynomial equation with interactions. Lipozyme enzymes were more tolerant to high temperatures in neem and shea oils reaction media compared to that of mango oil. The optimum reaction conditions EC, T, AWC, and RT assuring near complete conversion were as follows: mango oil 7.25 %, 36.6 °C, 10.9 %, 36.4 h; neem oil EC = 7.19 %, T = 45.7 °C, AWC = 8.43 %, RT = 25.08 h; and shea oil EC = 4.43 %, T = 45.65 °C, AWC = 6.21 % and RT = 25.08 h. Validation experiments of these optimum conditions gave ME yields of 98.1 ± 1.0, 98.5 ± 1.6 and 99.3 ± 0.4 % for mango, neem and shea oils, respectively, which all met ASTM biodiesel standards

Recent developments in the production of liquid fuels via catalytic conversion of microalgae: experiments and simulations

Due to continuing high demand, depletion of non-renewable resources and increasing concerns about climate change, the use of fossil fuel-derived transportation fuels faces relentless challenges both from a world markets and an environmental perspective. The production of renewable transportation fuel from microalgae continues to attract much attention because of its potential for fast growth rates, high oil content, ability to grow in unconventional scenarios, and inherent carbon neutrality. Moreover, the use of microalgae would minimize ‘‘food versus fuel’’ concerns associated with several biomass strategies, as microalgae do not compete with food crops in the food chain. This paper reviews the progress of recent research on the production of transportation fuels via homogeneous and heterogeneous catalytic conversions of microalgae. This review also describes the development of tools that may allow for a more fundamental understanding of catalyst selection and conversion processes using computational modelling. The catalytic conversion reaction pathways that have been investigated are fully discussed based on both experimental and theoretical approaches. Finally, this work makes several projections for the potential of various thermocatalytic pathways to produce alternative transportation fuels from algae, and identifies key areas where the authors feel that computational modelling should be directed to elucidate key information to optimize the process

Effects of Feeding Varying Levels of DL-Methionine on Live Performance and Yield of Broiler Chickens

This study was designed to evaluate the effects of dietary supplemental DL-methionine (MET) on live performance and meat yield for broilers raised to a common weight. A total of 1552 one-day old Ross 708, sexed broilers were randomly distributed to 32 pens resulting in eight treatments (TRT) of four replicates with 44 male or 53 female/pen. A randomized complete block with a 2 × 4 (sex × 4 MET levels 0, 0.5, 1, and 2 g/kg) factorial arrangement of TRT was used. A common weight of 2400 g was approached by day 46 (1 and 2 g MET/kg feed) and day 48 (0 and 0.5 g MET/kg feed). Supplementation of MET at 1, and 2 g/kg had a lower (p < 0.01) feed conversion ratio (FCR) at day 46/48 than broilers fed 0.5 g MET/kg. Broilers without supplemental MET had the worst (p < 0.01) feed conversion and average daily gain (ADG) at day 46/48. Birds fed 0 g MET/kg of feed had lower (p < 0.05) whole eviscerated carcass without giblets (WOG), yield than birds fed 2 g MET/kg of feed. Additionally, birds fed 0 g MET/kg of feed had lower (p < 0.05) breast fillet and tender percent yields than birds fed supplemental MET. Elimination of MET from organic broiler diets resulted in reduced ADG, breast fillet yield and feed efficiency of meat yield of broilers raised to day 46/48. Reduction in MET supplementation below current levels reduced the efficiency of meat production of organic broilers raised to day 46/48