Development of an effective High Temperature Fischer-Tropsch Synthesis (HTFTS) catalyst is of interest in process intensification that combines methane reforming with long chain hydrocarbon production. Literature indicates iron catalysts supported on mesoporous silica performed relatively well in high temperature applications. In this work, we investigated the effect of manganese promoter on iron catalysts for FTS at 430 °C as it was known from previous studies that manganese promotion could enhance the CO conversion with higher hydrocarbon yields. Also, the effect of temperature on FTS activity was evaluated by testing the base and promoted Fe/SBA-15 catalysts for temperature ranging from 370 to 430 °C. Incipient wetness impregnation method was used to prepare the catalysts. The catalysts used in this work were un-promoted iron (15 wt%) and Mn promoted (1.4, 2.8, 4.2, 5.6, 11.2 wt%) iron (15 wt%) catalysts supported on SBA-15. The catalysts were characterized using XRD, TPR, N2 Physisorption, and SEM. These catalysts were first activated in synthesis gas (H2: CO = 2:1) at 430 °C and then tested for their catalytic performance at the same temperature and atmospheric pressure. Prior work with SBA-15 supported iron catalysts showed that manganese promotion could improve the CO conversion when compared to copper and potassium. The main goal of this work was to study the effect of varying the manganese content on SBA-15 supported iron catalysts to determine the optimum loading of Mn along with the effect of temperature. It was found that CO conversion increases from 27% to74% with increasing the amount of manganese. The yield of CO2 increased substantially with higher Mn loadings. When different Mn promoted iron catalysts were compared, the catalysts with 2.8 wt% Mn loading showed the best performance in terms of the CO conversion and yield of C2+ hydrocarbons. Catalyst with 2.8 wt% of manganese loading yielded a CO conversion of 54%, with a methane yield of 17%, 32% (carbon) yield of C2- C4 and 9%(carbon) yields of C5+ hydrocarbon products, respectively. The effect of operating temperature on the catalytic performance of both the base catalyst 15Fe/SBA-15 and the promoted 2.8Mn/15Fe/SBA-15 catalyst was also examined. The unpromoted iron catalyst showed an improved catalytic activity at 400 °C with the total CO conversion of 38% and a higher yields of C5+ hydrocarbons. A significant decrease was also observed in the yields of CH4 and CO2. The methane and carbon dioxide yield increased from 11% and 8% to 25% and 40%, respectively, as the temperature increased from 400 to 450 °C. The catalyst with 2.8 wt% of manganese promotion gave better CO conversion and hydrocarbon product yields at 430 °C. Lower temperature showed negative effect on hydrocarbon product yield for manganese promoted catalysts.

[pt] A integração e o desenvolvimento das cadeias de suprimento representam um diferencial competitivo no ambiente corporativo. No mercado de biocombustíveis, essa análise torna-se ainda mais significativa, visto as baixas margens operacionais que o setor tem apresentado. Nessa dissertação, é proposta a análise do nível de maturidade entre cadeias de suprimentos agrícolas com o foco na produção de biocombustíveis no Brasil. Para realizar essa análise, foi desenvolvido um quadro analítico composto por indicadores com dois irecionadores principais, sendo o primeiro deles representando o nível de integração da rede de fornecedores, e o segundo representando o nível de desenvolvimento das operações logísticas. O resultado dessa análise demonstra, através de um gráfico de dispersão, como as cadeias da soja e da cana-de-açúcar estão em níveis de maturidade superiores a outras duas cadeias analisas, que são a palma e a mamona. / [en] The integration and development of the supply chain is a competitive advantage in the corporate environment. In the biofuels market, this analysis becomes even more significant, given the low operating margins that the sector has shown. In this dissertation we propose the analysis of the level of maturity between agricultural supply chains with a focus on producing biofuels in Brazil. For this analysis we have developed an analytical framework consisting of indicators with two main drivers, the first one represents the integration level of the supply chain, and the second one represents the development of logistics operations level such as transportation and industrial operation. The result of this analysis demonstrates, through a scatter plot, that the soybean and sugarcane chains are in maturity levels above than two other chains analyzed, the palm and castor bean.

The increasing demand for transportion fuels has led most countries around the world to look for alternatives to the predominant fossil fuels in the sector. Furthermore, the needs for security of energy supply, social – economic and sustainable development are among the factors driving the search for alternative fuels with regard to the fact that most oil producing countries are politically unstable. Developing countries are not an exception and are also formulating policies that will enhance development of alternatives to fossil fuels.   This study analyses the opportunities and consequences of the development of the biofuels industry in Zambia from a local, regional and global perspective with regard to policy, technical, socio – economic, environment and sustainability considerations. From analysis of global, regional and local situation, the development of biofuels in Zambia is simulated using Long – range Energy Alternatives Planning system (LEAP) under different policy assumptions with consideration of current and future demands. Furthermore, the socio – economic and environmental consequences are modelled in LEAP using these policies and other assumptions which include demand – cost projections. The environmental loadings are also simulated for the period with the assumption that biofuels are zero net emitters of green house gases. Land requirements are then estimated from these results for the simulated period. A model of illustrative scenarios for implementation of different biofuels policies is developed which can be used to monitor and analyse their consequences by adjusting the major parameters depending on varying circumstances.   The results of this study show that there is considerable potential for feedstock, land, water and mature technology for production of both biodiesel and bioethanol to meet blending demands for the simulated period. There is considerable potential for production of bioethanol from sugar cane and sweet sorghum using the well established fermentation processes. Biodiesel can be produced from jatropha and other oil bearing plants. Most of the current fleet of vehicles in Zambia was manufactured after 1990, thus there is little or no modification required on engines to run on low biofuel blends considered in the simulations. It is clear from the results of the simulation that biofuel demand for blends of 5% in 2015 rising to 10% in 2030 with current yields required for both can be achieved with the available land ad water resources. To achieve the 10% blending target set in the simulated period for bioethanol and biodiesel from sugar cane and jatropha, land required is 4,480Ha and 47,000Ha respectivey for growing this feedstock at current yields for the region. The GHG reduction would be equivalent to the 10% in 2030 if we assume that biofuels are zero net emitters. However, policies have to be formulated and implemented which should include manadatory blending targets and incentives on tax and investments.

Switchgrass (Panicum virgatum L.) is a promising bioenergy crop for biofuel production. However, the effects of biosolids application on biomass yield, nitrogen (N) concentration, feedstock quality and theoretical ethanol yield (TEY) are rarely reported in the literature. The objectives of this research were: 1) to compare the effects of biosolids application on biomass yield, N concentration, feedstock quality and TEY, and 2) to compare the effects of harvest frequency on biomass yield, N concentration, feedstock quality and TEY. This experiment began in 2010 and tested four plant available N (PAN) rates of biosolids (0, 153, 306, 459 kg ha-1), one urea rate (180 kg ha-1), and two harvest frequencies (cut once in November or cut in July and November) on a Davidson soil at Orange, VA. Biosolids and urea applications increased biomass yield and TEY across years relative to control, but had no effects on measures of feedstock quality. Inconsistent biomass yield responses to harvest frequency were observed during three years. Cutting once per year consistently increased biomass lignin, cellulose, and hemicellulose concentrations, theoretical ethanol potential (TEP), and reduced N and ash concentrations compared to two cuts. Across years one cut increased TEY by 11% over the two cuts. The results demonstrate that biosolids can be applied as an N source to increase biomass yield and TEY. Two cuts increased biomass yield but reduced TEP, and had inconsistent effects on TEY. / Master of Science

A current discussion of winner and loser is the issue of low-carbon development toward sustainability. Biofuel, as granted an important role to curtail the carbon emission and secure energy supply, has been also involved in this discussion. However, unfortunately, a biofuel potential has been raising fear worldwide since the surge of its development favors large-scale patterns, which are bringing widely social-economical and environmental impacts. How to foster strengths and circumvent weaknesses to plan this sector is the core of this paper. China has emerged to be the second economic entity with huge appetite for energy. This study is expected to explain China’s experiences in this field with guidance of effective biofuel planning.

The production of biofuels in South Africa has evolved very slowly and at present there are only a handful of plants producing some derivative of biofuel. The lack of commitment from government and the utter information distortion under which the current policy framework was developed have largely contributed to the current state of affairs. The manner in which the current policy framework was formulated based on the available information has impacted negatively on the development of the industry and it is hypothesised that had a better and more comprehensive analysis process been followed, the framework would be of such a nature that the industry could be sustainable in the long run. The study examines the policies and policy development process that have taken place in other biofuel producing countries and investigates the various policy instruments that are in use in these industries. The study further explores the interactions of industry role players at both government and producer level while attempting to explain the factors that could have caused their deviation from the rational and expected path of strategies and actions. In both games, each at a different level, the resultant Nash Equilibrium changes and prevailing strategies indicate that it is not in the role player's interest to commit to the industry. The government departments involved in formulating the biofuel policy seem to be uninformed and hence choose a low support route while oil companies consistently choose not to invest in capacity and biofuel refiners find their Nash Equilibrium at high levels of investment. A decision tree is formulated to conduct an in-depth review of the current level of profitability of proposed and current projects with specific reference to current legislation. The decision tree unpacks the current economic environment in the industry and identifies various factors that are crucial to the long-term development and growth of the industry. Based on this comprehensive survey of the industry and a detailed comparison of various production costs, together with the design of the game theoretic framework, a conceptual policy framework is designed and it is proposed that this replaces the current biofuel strategy. The new policy framework establishes its sustainable structure based on facts, detailed figures and existing project information. The framework is based on a more sustainable policy structure that combines elements of rural development with the economics that are required in order for the industry to be sustainable in the long run. Unlike the official government biofuels policy, the Industrial Biofuels Strategy, this proposed policy framework takes the industry's and role players' requirements into account and is designed in such a way that government targets and goals are accomplished. It is hypothesised that the implementation of this comprehensive policy framework will assist in the establishment of a successful and sustainable biofuels industry. Copyright / Thesis (DCom)--University of Pretoria, 2010. / Agricultural Economics, Extension and Rural Development / unrestricted

Thesis (Ph. D. (Microbiology)) -- University of Limpopo, 2019 / In an effort to align the current research with the country’s biofuel strategy, the aim of the study was to utilize banana pseudostem in the production of fungal cellulolytic enzymes and bioethanol through fermentation of the banana pseudostem hydrolysate. The selection of microorganisms was based on the ability of the fungi to grow on agar containing Avicel (microcrystalline cellulose) followed by assaying for cellulases in the form of endoglucanase and total cellulase activity. Ten fungal isolates obtained from screening process showed positive endoglucanase activity on carboxymethyl cellulose – Congo Red agar plate. The six fungal isolates selected based on high cellulase activity belonged to Trichoderma and Aspergillus genera. In submerged fermentation (SmF), the maximum cellulase and endoglucanase production under optimal conditions by all fungal isolates was achieved in media with an initial of pH 6.5 at 30 °C. Under these conditions, the total cellulase activity was 9.79 filter paper units (FPU)/mL and endoglucanase activity 45.2 U/mL for Trichoderma longibrachiatum LMLUL 14-1 and total cellulase activity of 7.7 FPU/mL and endoglucanase activity of 32.7 U/mL for Trichoderma harzianum LMLUL 13-5. These cellulase activities were higher than in the crude enzymes system for all Aspergillus fumigatus. The production conditions for maximum β-glucosidase varied amongst the Aspergillus spp. For example, Aspergillus fumigatus LMLUL 13-4 had produced higher β-glucosidase activity in a medium with an initial pH of 6.5 and at an incubation temperature of 30 °C whereas A. fumigatus LMLUL 13-1 had produced higher β-glucosidase activity at an initial pH of 7.0 and at 35 °C. Solid state fermentation (SSF) to produce cellulase enzymes system was influenced by temperature, nature of the substrate (i.e. moisture, modification) and culturing technique/strategy (i.e. monoculture versus co-culture). Higher cellulase enzymes system was produced under the conditions of 30 °C, 75% moisture content of untreated (native) BPS and pH 6.5. All the fungi investigated, produced thermotolerant and acidophilic cellulase and endoglucanase, whilst β-glucosidase is both acidophilic and alkaliphilic. The cellulase enzymes complex of T. harzianum LMLBP07 13-5 is most stable, followed by A. fumigatus LMLPS 13-4 and the least stable cellulase enzymes complex was for T. longibrachiatum LMLULSA 14-1. For the pretreatment of BPS, the material was first subjected to three different pretreatment conditions; namely alkaline (3% NaOH), acid (5% H2SO4) and hot water (autoclave method) pretreatment to remove lignin and loosen the cellulose structure. After the pretreatments, alkaline method exposed more cellulose than other pretreatments methods. The alkaline pretreated BPS contained 52.3% cellulose, 10.8% hemicellulose and 8.7% lignin, which is 2.3-fold more cellulose and 0.48-fold less hemicellulose as well as 0.6-fold less lignin to the native BPS. The enzymatic saccharification of the alkaline pretreated BPS at different substrate loadings at 50 °C for 76 hours by an individual crude cellulase enzymes system from T. longibrachiatum LMLSAUL 14-1 and T. harzianum LMLBP07 13-5 cultures were used at a final concentration of 10 FPU/g. Saccharification released maximum glucose of 43.5 g/L and 20.1 g/L form alkaline pretreated BPS by crude cellulase enzymes from T. longibrachiatum LMLSAUL 14-1 and T. harzianum LMLBP07 13-5 measured at the highest solid loading. The production of bioethanol was carried out in separate hydrolysis and fermentation (SHF). Fermentation of nutrient supplemented BPS hydrolysate with an initial pH of 5.0 by S. cerevisiae UL01 occurred at 30 °C for 48 hours. The maximum ethanol concentration obtained after fermentation was 17.6 g/L corresponding to ethanol yield of 60% of the maximum theoretical yield. In conclusion, banana pseudostem is a suitable alternative substrate for the production of second-generation bioethanol. / National Research Foundation (NRF) and Vlaamse Interuniversitaire Raad (VLIR- UOS)

Ignition and combustion characteristics of n-butanol/air, 2-butanol.air and isobutanol/air mixtures at stoichiometric (ϕ = 1) and lean (ϕ = 0.5) conditions were investigated in a micro flow reactor with a controlled temperature profile from 323 K to 1313 K, under atmospheric pressure. Sole distinctive weak flame was observed for each mixture, with inlet fuel/air mixture velocity set low at 2 cm/s. One-dimensional computation with comprehensive chemistry and transport was conducted. At low mixture velocities, one-stage oxidation was confirmed from heat release rate profiles, which was broadly in agreement with the experimental results. The weak flame positions were congruent with literature describing reactivity of the butanol isomers. These weak flame responses were also found to mirror the trend in Anti-Knock Indexes of the butanol isomers. Flux and sensitivity analyses were performed to investigate the fuel oxidation pathways at low and high temperatures. Further computational investigations on oxidation of butanol isomers at higher pressure of 5 atm indicated two-stage oxidation through the heat release rate profiles. Low temperature chemistry is accentuated in the region near the first weak cool flame for oxidation under higher pressure, and its impact on key species – such as hydroxyl radical, hydrogen peroxide and carbon monoxide – were considered. Both experimental and computational findings demonstrate the advantage of employing the micro flow reactor in investigating oxidation processes in the temperature region of interest along the reactor channel. By varying physical conditions such as pressure, the micro flow reactor system is proven to be highly beneficial in elucidating oxidation behavior of butanol isomers in conditions in engines such as those that mirror HCCI operations.

Microalgae have many desirable attributes as a renewable energy recourse. These include use of poor quality land, high yields, and it is not a food recourse. This research focusses on the energetic and environmental impact of processing microalgae into a renewable diesel. Two thermochemical bio-oil recovery processes are analyzed, pyrolysis and hydrothermal liquefaction (HTL). System boundaries include microalgae growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transportation to the pump. Two system models were developed, a small-scale experimental and an industrial-scale. The small-scale system model is based on experimental data and literature. The industrial-scale system model leverages the small scale system model with scaling and optimization to represent an industrial-scaled process. The HTL and pyrolysis pathways were evaluated based on net energy ratio (NER), defined here as energy consumed over energy produced, and global warming potential (GWP). NER results for biofuel production through the industrial-scaled HTL pathway were determined to be 1.23 with corresponding greenhouse gas (GHG) emissions of -11.4 g CO2 eq (MJ renewable diesel)-1. Biofuel production through the industrial-scaled pyrolysis pathway gives a NER of 2.27 and GHG emissions of 210 g CO2 eq (MJ renewable diesel)-1. For reference, conventional diesel has an NER of 0.2 and GHG emissions of 18.9 g CO2 eq MJ-1 with a similar system boundary. The large NER and GHG emissions associated with the pyrolysis pathway are attributed to feedstock drying requirements and combustion of co-products to improve system energetics. Process energetics with HTL and pyrolysis are not currently favorable for an industrial scaled system. However, processing of microalgae to biofuel with bio-oil recovery through HTL does produce a favorable environmental impact and a NER which is close to the breakeven point of one.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21132号 / 農博第2258号 / 新制||農||1056(附属図書館) / 学位論文||H30||N5106(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 加納 健司, 教授 小川 順, 教授 三芳 秀人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM