Energy demand is rapidly increasing due to the increase in population and rising living standards. Petroleum-based fuels account for the main source of energy consumed in the world. However, they are also considered to be the main source of the unwanted emissions to the atmosphere. In this context, chemical kinetic studies of combustion processes are essential for a better understanding of the underlying reactions and to achieve increased combustion efficiency and reduced pollutant emissions. In this study, ignition delay times, a global indicator of fuel reactivity, were measured for promising fuels for use in advanced combustion engines. Also, rate coefficients were measured for promising oxygenated hydrocarbons that can be used as additives to conventional fuels. Ignition delay time measurements of four primary reference fuel (PRF) blends, mixtures considered to be some of the simplest gasoline surrogates, were measured behind reflected shock waves to provide a large experimental dataset to validate PRF chemical kinetic models. The kinetic modeling predictions from four chemical kinetic models were compared with the experimental data. Ignition delay correlations were also developed to reduce the simulation cost of complicated models. Recently, naphtha, a low-octane distillate fuel, has been proposed as a low-cost refinery fuel. Likewise, a mid-octane blend which consists of low-octane (light and heavy naphtha) and high-octane (reformate) distillate fuels has been proposed to power gasoline compression ignition (GCI) engines. In this work, experimental and modeling studies were conducted on low and mid-octane distillate fuels (naphtha and GCI blend) and surrogate candidates to assess their autoignition characteristics for use in advanced internal combustion engines. Oxygenated molecules are considered to be promising additives to conventional fuels. Thermal decomposition of three esters (ethyl levulinate, ethyl propionate and diethyl carbonate ) and a five-member cyclic ketone (cyclopentanone) was investigated in this work. Laser absorption technique was employed to follow the reaction progress by measuring ethylene (C2H4) near 10.532 µm using a CO2 gas laser for the decomposition process of the three esters. The reaction progress of the decomposition of cyclopentanone was followed by monitoring CO formation using a quantum cascade laser at a wavelength near 4.556 µm.

China is a leading producer of alternative energy in the present day, while much of its economic rise under the CCP in the late 20th century was driven by the successful development of domestic coal and gas resources in the 1960s and 70s. But the drive to secure autonomous sources of energy to propel economic development and protect national security well predates China’s transition to socialism at midcentury. This dissertation explores the emergence of technocratic state rule in 20th century China by investigating the development of a biofuel industry designed to ensure energy security during war with imperial Japan. During the early to mid-1930s, Chiang Kai-Shek’s KMT government began supporting scientific research on ethanol-based biofuel production as a means of preserving fuel supplies should Japanese forces successfully blockade supply routes into the country during wartime. As exactly this scenario came to pass in the late 1930s, a network of more than 100 private and state-run ethanol plants were constructed along new roadways spanning the country’s southwestern interior. By 1945, millions of gallons a year of ethanol-based “dongli jiujing” fueled the logistical chains of both Chinese and US troops stationed throughout the China theater. The fusion of statecraft and science manifested in the dongli jiujing program both points forward to state-led energy and heavy industrial development in the 1950s and 1960s under Mao’s CCP, and represents one of the top accomplishments of KMT agencies like the National Resources Commission, a powerful technocratic agency which held up the wartime biofuel industry as a paradigmatic example of successful state-led economic development. While scholarship on heavy industry in China often focuses on the latter half of the 20th century, this dissertation demonstrates that by the mid 1930s, the development of the biofuel industry welded political visions for a sovereign, industrially powerful China with the technical expertise of chemists and microbiologists at the National Bureau of Industrial Research (NBIR), a state funded institution for applied science research oriented at developing heavy industries. And it points out that many of the scientists involved in the dongli jiujing program would continue development work in fields like agricultural chemistry and the biochemical industry under the CCP. Engaging with and contributing to recent scholarship on the history of science and technology in Asia, “Mobilizing Microbes” also traces the global circulation of fermentation-related knowledge that informed NBIR attempts to harness microbial life for the industrial production of alcohol. And finally, it explores connections that brought together in unexpected ways the craft knowledge and practices of China’s domestic brewing industry with modernizing visions for a powerful, fully sovereign China propounded by scientists and statesmen as the midpoint of the 20th century drew near.

Population growth and increasing standards of living have resulted in a rapid demand for energy. Our primary energy production is still dominated by fossil fuels. This extensive usage of fossil fuels has led to global warming, environmental pollution, as well as the depletion of hydrocarbon resources. The prevailing difficult situation offers not only a challenge but also an opportunity to search for alternatives to fossil fuels. Hence, there is an urgent need to explore environmentally friendly and cost-effective renewable energy sources. Oxygenates (alcohols, ethers) and ammonia are among the potential renewable alternative fuels of the future. This thesis investigates the combustion characteristics of promising alternative fuels and their blends using a combination of experimental and modelling methodologies. The studied fuels include ethanol, diethyl ether, dimethyl ether, dimethoxy methane, γ-valerolactone, cyclopentanone, and ammonia. For the results presented in this thesis, the studies may be classified into three main categories: 1. Ignition delay time measurements of ethanol and its blends by using a rapid compression machine and a shock tube. The blends studied include binary mixtures of ethanol/diethyl ether and ternary mixtures of ethanol/diethyl ether/ethyl levulinate. A chemical kinetic model has been constructed and validated over a wide range of experimental conditions. The results showed that a high-reactivity fuel, diethyl ether, may be blended with a low-reactivity fuel, ethanol, in varying concentrations to achieve the desired combustion characteristics. A ternary blend of ethanol/diethyl ether/ethyl levulinate may be formulated from a single production stream, and this blend is shown to behave similarly to a conventional gasoline. 2. Ignition delay time and flame speed measurements of ammonia blended with combustion promoters by utilizing a rapid compression machine and a constant volume spherical reactor. The extremely low reactivity of ammonia makes it unsuitable for direct use in many combustion systems. One of the potential strategies to utilize ammonia is to blend it with a combustion promoter. In this work, dimethyl ether, diethyl ether, and dimethoxy methane are explored as potential promoters of ammonia combustion. Chemical kinetic models were developed and validated in the high temperature regime by using flame speed data and in the low-to-intermediate temperature regime by using ignition delay time data. The results showed that even a small addition (~ 5 – 10%) of combustion promoters can significantly alter ammonia combustion, and diethyl ether was found to have the highest propensity to enhance ammonia ignition and flame propagation. Blends of combustion promoters with ammonia can thus be utilized in modern downsized turbo-charged engines. 3. Octane boosting and emissions minimization effects of next generation oxygenated biofuels. These studies were carried out using a cooperative fuel research engine operating in a homogenous charge compression ignition (HCCI) mode. The oxygenated fuels considered here include γ-valerolactone and cyclopentanone. The results showed that γ-valerolactone and cyclopentanone can be effective additives for octane boosting and emission reduction of conventional fuels. Overall, the results and outcomes of this thesis will be highly useful in choosing and optimizing alternative fuels for future transportation systems.

<div>Due to the depletion of fossil fuel reserves and emission challenges associated with its usage, there is a need for alternative aviation fuels for future propulsion. The alternative fuels with handling, storage and combustion characteristics similar to conventional fuels can be used as “drop-in” fuels without significant changes to the existing aviation infrastructure. Fire safety characteristics of alternative aviation fuels have not been studied intensively and therefore research is needed to understand these characteristics. In this study, fire safety characteristics namely hot surface ignition (HSI) and flame spread phenomena are investigated for alternative aviation fuels. </div><div><br></div><div>HSI is defined as the process of a flammable liquid coming in contact with a hot surface and evaporating, mixing and reacting with the surrounding oxidizer with self-supporting heat release (combustion). If all the conditions are adequate, the fuel may completely turn into combustion products following the ignition process. This work presents results from more than 5000 ignition tests using a newly developed reproducible test apparatus. A uniform surface temperature stainless steel plate simulating the wall of a typical exhaust manifold of an aircraft engine is used as the hot surface. Ignition tests confirmed that the ignition event is transient and initiates at randomly distributed locations on the hot surface. The results show many significant differences and some similarities in the ignition characteristics and temperatures of the different fuels. In this work, hot surface ignition temperatures (HSITs) are measured for nine hydrocarbon liquids. Five of these fuels are piston engine based, three fuels are turbine-engine based and one fuel is a pure liquid, heptane. The piston engine based fuels are given by FAA and are confidential and hence labeled as test fuels A, B, C, D for this study. The HSITs of these fuels are measured and compared against a baseline fuel 100 LL aviation gasoline (100LL Avgas). HSITs of conventional turbine engine based fuels namely Jet-A, JP-8, and JP-5 are also measured. </div><div><br></div><div>Flame spread along liquid fuel has been one of the important combustion phenomena that still requires more in-depth research and analysis for the deep understanding of the chemical processes involved. Flame spread rate determines how fast the flame spreads along the fuel surface and it is an important parameter to study for fire safety purposes. For the flame spread rates study, a novel experimental apparatus is designed and fabricated. The experimental apparatus consists of a rectangular pan, a fuel heating system, an autonomous lid actuation system, a CO2 fire extinguisher system, and a laser ignition system. The flame spread phenomenon is studied for a conventional aviation fuel namely, Jet-A and three alternative aviation fuels namely, hydro-processed ester fatty acids (HEFA-50), Fischer-Tropsch – IPK (FT-IPK) and synthetic iso-paraffin (SIP). The experiments are conducted for a wide range of initial fuel temperatures ranging from 25°-100°C for Jet-A, HEFA-50, FT-IPK and from 80-140°C for SIP as the flash-point of SIP is 110°C and is ~3 times higher than that of other three fuels. The flame spread rate of all fuels increases exponentially with increasing fuel’s initial temperature. Flame spread rate is as low as ~5 cm/sec for Jet-A, HEFA-50, FT-IPK for 25°C initial fuel temperature and goes to as high as 160 cm/sec for 80°C initial fuel temperature. For SIP based jet fuel, flame spread rate is ~160 cm/sec for initial fuel temperature of 140°C. Additionally, it was also found that the flame propagation consists of two types of flames: a precursor blue flame located ahead of the main yellow flame. These flames are more evident over the fuels’ surface with initial fuel temperatures higher than their respective flash-points. The precursor blue flame propagates like a premixed flame and the main yellow flame propagates like diffusion combustion.</div><div><br></div><div>This dissertation includes eight chapters. Chapter 1 gives an overview of the work done until now in the field of hot surface ignition. Following this review, the experimental apparatus designed and fabricated for this study are discussed in Chapter 2. This chapter also talks about the test matrix, data acquisition tools and concludes with the data analysis method. In Chapter-3, HSITs of 3 turbine engine based fuels and 5 piston engine based fuels are reported. This chapter also discusses the effect of drop height and curvature (flat v/s cylindrical) for two fuels, Jet-A, and heptane. This concludes the work done in the field of HSI in this dissertation. Chapter 4 talks about the past work reported by various researchers in the field of flame spread phenomenon and key learnings from their work. Chapter 5 discusses the experimental apparatus designed and fabricated for flame spread phenomenon study. In chapter-6, flame spread rates of 4 alternative aviation fuels are reported. This chapter also discusses the flame spread mechanism associated with slower (liquid-phase controlled) and faster (gas-phase controlled) flame propagation. Chapter 7 discusses flame propagation which consists two types of flames: a precursor blue flame and a main yellow flame. Chapter 8 concludes the key findings of the hot surface ignition and flame spread phenomenon study in this research work </div><div><br></div>

<p>The main accomplishments of this research are </p> <p>(1) developed a high fidelity computational methodology based on large eddy simulation to capture lean blowout (LBO) behaviors of different fuels; </p> <p>(2) developed fundamental insights into the combustion processes leading to the flame blowout and fuel composition effects on the lean blowout limits; </p> <p>(3) developed artificial intelligence-based models for early detection of the onset of the lean blowout in a realistic complex combustor. </p> <p>The methodologies are demonstrated by performing the lean blowout (LBO) calculations and statistical analysis for a conventional (A-2) and an alternative bio-jet fuel (C-1).</p> <p>High-performance computing methodology is developed based on the large eddy simulation (LES) turbulence models, detailed chemistry and flamelet based combustion models. This methodology is employed for predicting the combustion characteristics of the conventional fuels and bio-derived alternative jet fuels in a realistic gas turbine engine. The uniqueness of this methodology is the inclusion of as-it-is combustor hardware details such as complex hybrid-airblast fuel injector, thousands of tiny effusion holes, primary and secondary dilution holes on the liners, and the use of highly automated on the fly meshing with adaptive mesh refinement. The flow split and mesh sensitivity study are performed under non-reacting conditions. The reacting LES simulations are performed with two combustion models (finite rate chemistry and flamelet generated manifold models) and four different chemical kinetic mechanisms. The reacting spray characteristics and flame shape are compared with the experiment at the near lean blowout stable condition for both the combustion models. The LES simulations are performed by a gradual reduction in the fuel flow rate in a stepwise manner until a lean blowout is reached. The computational methodology has predicted the fuel sensitivity to lean blowout accurately with correct trends between the conventional and alternative bio-jet fuels. The flamelet generated manifold (FGM) model showed 60% reduction in the computational time compared to the finite rate chemistry model. </p> <p>The statistical analyses of the results from the high fidelity LES simulations are performed to gain fundamental insights into the LBO process and identify the key markers to predict the incipient LBO condition in swirl-stabilized spray combustion. The bio-jet fuel (C-1) exhibits significantly larger CH₂O concentrations in the fuel-rich regions compared to the conventional petroleum fuel (A-2) at the same equivalence ratio. It is observed from the analysis that the concentration of formaldehyde increases significantly in the primary zone indicating partial oxidation as we approach the LBO limit. The analysis also showed that the temperature of the recirculating hot gases is also an important parameter for maintaining a stable flame. If this temperature falls below a certain threshold value for a given fuel, the evaporation rates and heat release rated decreases significantly and consequently leading to the global extinction phenomena called lean blowout. The present study established the minimum recirculating gas temperature needed to maintain a stable flame for the A-2 and C-1 fuels. </p> The artificial intelligence (AI) models are developed based on high fidelity LES data for early identification of the incipient LBO condition in a realistic gas turbine combustor under engine relevant conditions. The first approach is based on the sensor-based monitoring at the optimal probe locations within a realistic gas turbine engine combustor for quantities of interest using the Support Vector Machine (SVM). Optimal sensor locations are found to be in the flame root region and were effective in detecting the onset of LBO ~20ms ahead of the event. The second approach is based on the spatiotemporal features in the primary zone of the combustor. A convolutional autoencoder is trained for feature extraction from the mass fraction of the OH ( data for all time-steps resulting in significant dimensionality reduction. The extracted features along with the ground truth labels are used to train the support vector machine (SVM) model for binary classification. The LBO indicator is defined as the output of the SVM model, 1 for unstable and 0 for stable. The LBO indicator stabilized to the value of 1 approximately 30 ms before complete blowout.

This dissertation examines the explosion of the cultural field in Venezuela during the 1970s oil boom through the lens of nature-society relations. I argue that cultural production was an agent of state-led ecological transformation and, at the same time, a space where artists and intellectuals negotiated spaces of autonomy that nonetheless were entangled with oil-funded projects of environment-making. By analyzing the cultural politics, visual arts, institutions, and infrastructure projects that blossomed during this era, I seek to uncover the role of cultural and aesthetic forms in processes of rapid urbanization and large-scale resource extraction. In doing so, I situate my work within recent efforts in the environmental humanities aimed at picking apart the cultural narratives that sustain or challenge the power of extractive regimes, particularly in the global South. My chapters analyze the cultural policies that oil-money made possible, the visual art that intersected with energy infrastructure projects, and the photography and film that dealt with the shocks of accelerated development and oil-led globalization. Supported by archival research and close examinations of understudied examples, I focus on the debates and cultural politics that defined the transition from the Instituto National de Cultura y Bellas Artes (Inciba) to the more powerful Centro Nacional de la Cultura (Conac); the role of the kinetic artworks of Carlos Cruz-Diez and Alejandro Otero in urbanization projects and the construction of the Guri hydroelectric dam in South-Eastern Venezuela; the photographic making of Caracas during the 1970s construction boom in the books of Soledad Mendoza and Ramón Paolini; and, finally, the crisis and breakdown of the dream of unlimited wealth in two film pieces by Carlos Oteyza and Antonio Llerandi. While studies about oil and cultural production usually trace the relations between fossil fuels and the formation of modernity in the global North, I contend that a vision from the nature-exporting societies of the global South is fundamental to understand the cultural logics of nature extraction at a planetary scale. Similarly, I propose that the relationship between culture and petroleum will not be clarified by tracking its representations in literary or artistic works, but rather by looking at how often the realm of culture is already intertwined with a global ecology of nature, capital, and power. Finally, in arguing this, I seek to highlight the cultural work of states in the extractive peripheries as an essential object of analysis for the environmental humanities, as well as for a broader rethinking of the uneven ecology of capitalism and the geopolitics of socioecological change.

Current global demands for energy resources along with continuous global population growth have placed natural environments and societies under great stress to fulfill such a need without disrupting economic and social structures. Policy and decision-making processes hold some of the most important keys to allow safe paths for societies towards energy security and safeguard of the environment. Brazil has played a lead role within renewable energy production and use during the last decades, becoming one of the world’s leading producer of sugarcane based ethanol and adapting policies to support renewable energy generation and use. Although it is true that Brazil has historic experience with managing development of renewables and its further integration into the consumer market, there is still a lot to do to impulse new technologies that could further reduce emissions, increase economic stability and social welfare. Throughout this thesis project a sustainability assessment of hydrogen production technologies in Brazil is conducted through Multi-Criteria Analysis. After defining an initial framework for decision-making, options for hydrogen production were reviewed and selected. Options were evaluated and weighted against selected sustainability indicators that fitted the established framework within a weighting matrix. An overall score was obtained after the assessment, which ranked hydrogen production techniques based on renewable energy sources in first place. Final scoring of options was analyzed and concluded that several approaches could be taken in interpreting results and their further integration into policy making. Concluding that selection of the right approach is dependent on the time scale targeted for implementation amongst other multi-disciplinary factors, the use of MCA as an evaluation tool along with overarching sustainability indicators can aid in narrowing uncertainties and providing a clear understanding of the variables surrounding the problem at hand.

Ship exhausts contain high levels of sulphur oxides, nitrogen oxides, carbon dioxide and particles dueto the heavy fuel oil, HFO, used for combustion and the combustion characteristics of the engine.As a result of upcoming stricter regulations for shipping pollution, as well as growing attentionto greenhouse gas emissions, air pollution and uncertainty of future petroleum oil supply, a shifttowards a cleaner burning fuel is needed.This work explores potential alternative fuels, both conventional and unconventional, and abatementtechnologies, to be used by tankers in the worldwide spot market to comply with upcomingenvironmental regulations in the near and coming future. As a reference the product tanker M/TGotland Marieann is used and recommendations for which fuel that shall be used by the referenceship in 2015 and 2020 are presented.The environmental assessment and evaluation of the fuels are done from a life cycle perspective usingresults from Life Cycle Assessment, LCA, studies.This study illustrates that, of the various alternatives, methanol appears to be the best candidatefor long-term, widespread replacement of petroleum-based fuels within tanker shipping. It does notemit any sulphur oxides nor particles and the nitrogen oxides are shown to be lower than those ofmarine gas oil, MGO. The global warming potential of the natural gas produced methanol is notlower than that of MGO, but when gradually switching to bio-methanol the greenhouse gas emissionsare decreasing and with methanol the vision of a carbon free society can be reached.For 2015 a switch towards methanol is not seen as realistic. Further research and establishment ofregulations and distribution systems are needed, however there are indications that a shift will bepossible sometime between 2015 and 2020. For 2015 a shift towards MGO is suggested as it involveslow investment costs and there is no need for infrastructure changes. As MGO is more expensivethan methanol, a shift is preferable as soon as the market, technology and infrastructure are ready.

Globally, transport accounts for a significant part of the total energy utilization and is heavily dominated by fossil fuels. The main challenge is how the greenhouse gas emissions in road transport can be addressed. Moreover, the use of fossil fuels in road transport makes most countries or regions dependent on those with oil and/or gas assets. With that said, the question arises of what can be done to reduce the levels of greenhouse gas emissions and furthermore reduce dependency on oil? One angle is to study what source of energy is used. Biomass is considered to be an important energy contributor in future transport and has been a reliable energy source for a long time. However, it is commonly known that biomass alone cannot sustain the energy needs in the transport sector by far. This work presents an alternative where renewable electricity could play a significant role in road transport within a relatively short time period. Today the amount of electricity used in road transport is negligible but has a potential to contribute substantially. It is suggested that the electricity should be stored, or “packaged” in a chemical manner, as a way of conserving the electrical energy. One way of doing so is to chemically synthesize fuels. It has been investigated how a fossil free transport system could be designed, to reach high levels of self-sufficiency. According to the studies, renewable electricity could have the single most important role in such a system.    Among the synthetic fuels, synthetic methane (also called synthetic biogas) is the main focus of the thesis. Hydrogen is obtained through water electrolysis, driven by electricity (preferable renewable), and reacted with carbon dioxide to produce synthetic methane. The concept of the mentioned process goes under the name Power to Gas. The electricity to fuel efficiency of such a process reaches about 50 %, but if utilizing excess heat produced during the electrolysis and the reaction, the total process efficiency can reach much higher levels. The economics of the process is as important as the technology itself in terms of large scale implementation. The price of electricity and biogas are the most important influences on the economic viability. The minimum “spread” between purchase and selling price can be determined to obtain a general perception of the economic feasibility. In this case biogas must be sold about 2.6 times higher than purchased electricity per kWh. / <p>QC 20130111</p>

With limited indigenous conventional energy resources, Mauritius imports over 80% of its energy supply from foreign countries, mostly from the Middle East. Developing independent renewable energy resources is thus of priority concern for the Mauritian government. A tropical island surrounded by the Indian Ocean, Mauritius has enormous potential to develop various renewable energies, such as solar energy, biomass energy, wind power, geothermal energy, hydropower, etc. However, owing to the importance of conventional fossil energy in generating remarkably cheap electricity, renewable energy has not yet fully developed in Mauritius, resulting from a lack of market competition. So, in order to reduce the external dependency of fuel, and also to cut down the expenses involved in the imported fuels, the Mauritius Government introduced attractive policies and invited investors of the homeland and abroad to invest in renewable energy technologies. Consequently, numerous promotional and subsidy programs have recently been proclaimed by the Mauritian government, focused on the development of various renewable energies. Thus, the Government of Mauritius has a long-term vision of transforming Mauritius into a sustainable Island. One important element towards the achievement of this vision is to increase the country’s renewable energy usage and thereby reducing dependence on fossil fuels. Democratisation of energy production is determined to be the way forward. A step in this direction is to transfer citizens the ability and motivation to produce electricity via small-scale distributed generation (SSDG), i.e. wind, photovoltaic, Hydropower. As a stepping stone the Government and the Central Electricity Board, with the help of the UNDP, established a grid code in May 2009 which encompasses tariffs and incentive schemes that have in many countries proved essential in order to achieve any substantial development in renewable electricity production based on SSDG.   In line with the government’s vision on renewable energy, the University of Mauritius is working as a partner with DIREKT team to promote renewable energy infrastructure locally. The DIREKT (Small Developing Island Renewable Energy Knowledge and Technology Transfer Network) is a teamwork scheme that involves the participation and collaboration of various universities from Germany, Fiji, Mauritius, Barbados and Trinidad &amp; Tobago.  The aim of the DIREKT project is to reinforce the science and technology competency in the domain of renewable energy through technology transfer, information exchange and networking, targeting ACP (Africa, Caribbean, Pacific) Small Island developing states. This study was therefore initiated to investigate the main renewable energy technologies that stakeholders, institutions as well as businesses and organizations would like to invest in Mauritius based in the attracting incentive schemes provided by the Government.   From the study it was found that the majority of the Organizations, Institutions, Businesses and stakeholders are ready to accept and invest in the solar photovoltaic technology. Moreover, the economic evaluation for the implementation of the photovoltaic technology revealed that within a period of 4.3 years (payback period), the total capital invested can be recovered and after that, the capital generated from the excess electricity produced will contribute to the profit of the organization, Business or Institution.