Download or read book Fuels Combustion Research Supercritical Fuel Pyrolysis written by and published by . This book was released on 2002 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercritical pyrolysis experiments were conducted with toluene, methyl cyclohexane, and n-heptane at temperatures up to 585 C, pressures up to 100 atm, and residence times up to 550 sec Analysis, by HPLC/UV, of the toluene reaction products led to the unequivocal identification of 27 individual PAH, up to 10 rings in size. The experiments showed that PAH yields increased exponentially with pressure. For each of the product PAH, values of the preexponential factor. A arid the activation volume V ̂were determined for the pressure-dependent global first-order kinetic rate constant. PAH yields were also extremely sensitive to temperature. At 100 atm and 480 C, PAH of only up to 2 rings were observed; at 535 C, PAH up to 10 rings were formed; at 585 C, solid deposits formed, plugging the reactor. Similar pressure and temperature sensitivities were exhibited by the PAH produced by methyl cyclohexane. The nature of the PAH product distributions suggested that condensation reactions, involving the addition of aromatic structures and hydrogen loss, were a dominant mechanism for PAH formation in the supercritical environment.

Download or read book Supercritical Fuel Pyrolysis written by and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fuels used in the next generation of hypersonic aircraft will have to operate under very high pressures (beyond the critical pressures of most hydrocarbons) and will have to sustain very high heat loads in order to meet aircraft cooling requirements. Critical to the development of the fuel systems in these aircraft is an understanding of the fuel pyrolysis reaction mechanisms under the conditions that the fuels will be operating. Of particular interest are the reactions leading to polycyclic aromatic hydrocarbons (PAH), which can serve as precursors to fuel-line deposits [3,4], a problem of critical importance to avoid, for safe aircraft operation. In order to better elucidate the mechanisms and kinetics of the reactions of fuel pyrolysis and PAH formation under supercritical conditions, pyrolysis experiments are being conducted, under the present research program, with model fuels at temperatures of 300-600 C, pressures of 20-100 atm, and residence times of 30-1000 sec. The model fuels include the jet fuel components toluene, 1-methylnaphthalene, and mixtures of toluene and n-heptane-as well as the "endothermic" fuel methylcyclohexane. The supercritical pyrolysis experiments are conducted in an isothermal silica-lined stainless-steel coil reactor specially designed [4,5] for such experiments, and PAH reaction products are analyzed by high-pressure liquid chromatography with diode-array ultraviolet-visible absorbance and mass spectrometric detection (HPLC/UV/MS), an isomer-specific technique ideally suited for the analysis of PAH [6]. It is anticipated that the results from this research will provide information of critical importance to the design and development of fuel systems for high-speed aircraft.

Download or read book Understanding the Role of Multifunctional Nanoengineered Particulate Additives on Supercritical Pyrolysis and Combustion of Hydrocarbon Fuels propellants written by Hyung Sim and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation aims to understand the fundamental effects of colloidal nanostructured materials on the supercritical pyrolysis, injection, ignition, and combustion of hydrocarbon fuels/propellants. As a fuel additive, functionalized graphene sheets (FGS) without or with the decoration of metal catalysts, such as platinum (Pt) or polyoxometalates (POM) nanoparticles, were examined against conventional materials including nanometer sized fumed silica and aluminum particles. Supercritical pyrolysis experiments were performed as a function of temperature, residence time, and particle type, using a high pressure and temperature flow reactor designed to provide isothermal and isobaric flow conditions. Supercritical pyrolysis results showed that the addition of FGS-based particles at a loading concentration of 50 ppmw increased the conversion rates and reduced apparent activation energies for methylcyclohexane (MCH) and n-dodecane (n-C12H26) fuels. For example, conversion rates, and formations of C1-C5 n-alkanes and C2-C6 1-alkenes were significantly increased by 43.5 %, 59.1 %, and 50.0 % for MCH decomposition using FGS19 (50 ppmw) at a temperature of 820 K and reduced pressure of 1.36. In addition, FGS decorated with 20 wt % Pt (20wt%Pt@FGS) at a loading concentration of 50 ppmw exhibited additional enhancement in the conversion rate of n-C12H26 by up to 24.0 % compared to FGS. Especially, FGS-based particles seem to alter initiation mechanisms, which could result in higher hydrogen formation. Hydrogen selectivities for both MCH and n-C12H26 decompositions were observed to increase by nearly a factor of 2 and 10, respectively. Supercritical injection and combustion experiments were conducted using a high pressure and temperature windowed combustion chamber coupled to the flow reactor through a feed system. Supercritical injection/combustion experiments indicated that the presence of a small amount of particles (100 ppmw) in the fuel affected the injection, ignition, and subsequent combustion for hydrocarbon fuels. For instance, the addition of Pt@FGS reduced the core lengths of the supercritical jets by up to 56.7 % (MCH) and 68.8 % (n-C12H26) depending on flow rate. Supercritical combustion studies demonstrated that the addition of 100 ppmw 20wt%Pt@FGS to n-C12H26 fuel reduced ignition delay times by nearly a factor of 3 (12.4 to 4.1 ms), increased spreading angles by approximately 32.0 % (15.4 to 20.3o), reduced the flame lift-off length by 54.0 % (1.74 to 0.8 mm), and demonstrated an increase in conversion by 35.0 % relative to the pure fuel baseline at a volumetric flow rate of 5.0 mL/min. The enhancing mechanisms of FGS-based materials on pyrolysis and combustion were studied using ReaxFF molecular dynamics (MD) simulation. The simulation results were in good agreement with the experimental observations, showing enhanced conversion rates and lowered activation energies in the presence of the particles. A combination of Pt and FGS facilitated catalytic dehydrogenation forming a n-C12H25 radical. Another catalytic initiation step is hydrogenation of the fuel molecule resulting in production of an alkanium ion, as a free hydrogen atom is donated to the fuel molecule. Furthermore, hydroxyl radical (OH), which is dissociated from FGS, was found to participate in dehydrogenation of the fuel forming water molecules. The recovery of the catalyst was observed, resulting from dissociation of H2 molecule from the surface of the Pt. Using the ReaxFF embedded with nudged elastic band (NEB) method, it was found that the bicomposite structure of Pt@FGS served to lower the reaction energy and energy barrier for dehydrogenation, which could result in the enhanced conversion rates and increased product yields. These results demonstrate that a low mass loading of a high surface area material employed either as an additive or a means of distributing another additive can significantly enhance, and be used to tailor, the conversion of liquid hydrocarbon fuels/propellants under supercritical conditions, resulting in reduced ignition delay time and improved combustion. Such enhancements benefit practical propulsion systems which require high conversion efficiency in a short residence time.

Download or read book Fundamentals of Thermochemical Biomass Conversion written by R.P. Overend and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout the world many projects have been underway to investigate the conversion of renewable biomass into energy and synthetic fuels by thermo chemical methods such as combustion, pyrolysis, gasification and lique faction. While many of these represent prior art used during the early 20th century, the recent decade since the 1970s oil shock has immeasurably increased the knowledge base for such processes. Much of the new knowledge has been gained by persons who were not trained in classical wood chemistry and there have not yet been many attempts to synthesize the knowledge into a corpus of systematic information. To bring this about the International Energy Agency's Forestry Energy collaboration, the Gas Research Institute, the National Research Council of Canada and the US Department of Energy jointly sponsored a conference on the Fundamentals of Thermochemical Biomass Conversion in Estes Park, Colorado which was held on October 18-22, 1982. The Conference, which was structured around invited plenary papers and contributions from researchers, served as the basis for the papers in this volume which reflect the substantial conclusions of the Conference. During the planning for the Conference, it was realized by the editors in their capacity as Co-chairmen that a major problem in biomass research was the lack of reproducibility between reported experiments and their inter comparison on account of the heterogeneity of biomass materials. A well known wood chemist, George M.

Download or read book The Effect of Reduced Extractive Content on the Burning Rate of Aspen Leaves written by Charles W. Philpot and published by . This book was released on 1969 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Review and Evaluation of the Air Force Hypersonic Technology Program written by National Research Council and published by National Academies Press. This book was released on 1998-09-05 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken in response to a request by the U.S. Air Force that the National Research Council (NRC) examine whether the technologies that underlie the concept of a hypersonic, air-launched, air-breathing, hydrocarbon-fueled missile with speeds up to Mach 81 can be demonstrated in time to be initially operational by 2015. To conduct the study, the NRC appointed the Committee on Review and Evaluation of the Air Force Hypersonic Technology Program, under the auspices of the Air Force Science and Technology Board.

Download or read book Supercritical Pyrolysis of the Endothermic Fuels Methylcyclohexane Decalin and Tetralin written by John Francis Stewart and published by . This book was released on 1999 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pyrolysis and Gasification written by G.L. Ferrero and published by Springer. This book was released on 1989-12-31 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Army Research Office and Air Force Office of Scientific Research 2002 Contractors Meeting in Chemical Propulsion written by David M. Mann and published by . This book was released on 2002 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstracts are given for 6.1 basic research in chemical propulsion sponsored by the Army Research Office and the Air Force Office of Scientific Research.

Download or read book Effect of Fuel Chemical Composition on Pyrolytic Reactivity and Deposition Propensity Under Supercritical Conditions written by Brian Philip McMasters and published by . This book was released on 2014 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: As modern hypersonic aircraft designs evolve, increasing heat sink capabilities are required. One potential approach is the use of endothermic fuels, which supplement fuel heat sink via sensible heating with endothermic chemical reactions. Endothermic reactions can proceed by thermal or catalytic decomposition of the fuel. Regardless of the specific methodology, thermal decomposition (pyrolysis) will occur at the expected reaction conditions. Improved understanding of the effect of chemical composition on supercritical pyrolytic reactivity and deposition propensity is needed to provide a basis of understanding for advanced fuel and system development. In this effort, a small-scale flow reactor system was developed to study the reactivity and deposition propensity of various hydrocarbon fuels and solvents of differing chemical composition. Experimental and computational studies were performed to investigate the relationship between fuel chemical composition and reactivity under supercritical conditions. Nine fuels and solvents of varying chemical composition were studied to evaluate pyrolytic reactivity and decomposition pathways. Chemical classes studied included normal paraffins, iso paraffins, and cycloparaffins in various combinations. Experimental studies were performed at reaction temperatures of 500-650℗ʻC and inlet flow rates of 0.50-3.00 mL/min, with a nominal system pressure of 500 psig. Corresponding equivalent residence times at these reaction conditions ranged from 0.2-11.4 sec. A fuel conversion metric was defined to allow comparison of the reactivity of multi-component fuels at equivalent inlet reaction conditions. Normal and iso-paraffinic solvents, as well as a blend of the two, had similar overall reactivities at equivalent inlet reactor conditions. Normal paraffins formed primarily lower-molecular weight normal paraffins and a-olefins, while iso-paraffins formed primarily lower-molecular weight iso-paraffins and branched olefins. It was observed that normal paraffins decomposed at a higher rate than iso paraffins in a blend of the two classes, indicating that iso-paraffins accelerate the relative decomposition rate of the linear compounds. Fuels and solvents with cycloparaffins had lower extents of conversion at equivalent reaction conditions. Aromatic species were formed at higher yields from fuels and solvents with higher cycloparaffin concentrations. It was observed that multi-component solvents decomposed under similar reaction pathways to single-component compounds; likewise, fully formulated fuels were found to decompose under similar pathways to multi component solvents of similar chemical compositions. The supercritical pyrolysis of the fuels and solvents was modeled as a first-order irreversible reaction to assist with reactivity comparisons among fuels and allow subsequent predictions. Supercritical pyrolysis was found to deviate from first-order reaction behavior at high conversion levels (> 30%), which limited the use of this simple kinetic analysis. The normal paraffinic solvent (Norpar-13) had estimated kinetic parameters of 60.7 kcal/mol activation energy and 1015· s−1 pre-exponential factor, while a specification JP-7 fuel sample was found to have kinetic parameters of 56.2 kcal/mol and 1013·5 s−1. Valid kinetic analysis is dependent upon accurate modeling of physical properties for estimation of residence times. A preliminary investigation of the deposition propensity of seven fuels and solvents was also performed in this effort. Significant differences in deposition rates were observed between fuels and solvents with similar chemical compositions, indicating that deposition propensity may not be solely determined by bulk chemical composition. Further investigation is needed to better understand the mechanisms of deposition formation in supercritical pyrolysis.

Download or read book Supercritical Fluid Technology for Energy and Environmental Applications written by Vladimir Anikeev and published by Newnes. This book was released on 2013-12-21 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercritical Fluid Technology for Energy and Environmental Applications covers the fundamental principles involved in the preparation and characterization of supercritical fluids (SCFs) used in the energy production and other environmental applications. Energy production from diversified resources — including renewable materials — using clean processes can be accomplished using technologies like SCFs. This book is focused on critical issues scientists and engineers face in applying SCFs to energy production and environmental protection, the innovative solutions they have found, and the challenges they need to overcome. The book also covers the basics of sub- and supercritical fluids, like the thermodynamics of phase and chemical equilibria, mathematical modeling, and process calculations. A supercritical fluid is any substance at a temperature and pressure above its critical point where distinct liquid and gas phases do not exist. At this state the compound demonstrates unique properties, which can be "fine-tuned," making them suitable as organic solvents in a range of industrial and laboratory processes. This volume enables readers to select the most appropriate medium for a specific situation. It helps instructors prepare course material for graduate and postgraduate courses in the area of chemistry, chemical engineering, and environmental engineering. And it helps professional engineers learn supercritical fluid-based technologies and use them in solving the increasingly challenging environmental issues. Relates theory, chemical characteristics, and properties of the particular supercritical fluid to its various applications Covers the fundamentals of supercritical fluids, like thermodynamics of phase and chemical equilibria, mathematical modeling, and process calculations Includes the most recent applications of supercritical fluids, including energy generation, materials synthesis, and environmental protection

Download or read book Biomass Gasification Pyrolysis and Torrefaction written by Prabir Basu and published by Academic Press. This book was released on 2013-07-18 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomass is the most widely used non-fossil fuel in the world. Biomass resources show a considerable potential in the long-term given the increasing proliferation of dedicated energy crops for biofuels. The second edition of Biomass Gasification and Pyrolysis is enhanced with new topics, such as torrefaction and cofiring, making it a versatile resource that not only explains the basic principles of energy conversion systems, but also provides valuable insight into the design of biomass conversion systems. This book will allow professionals, such as engineers, scientists, and operating personnel of biomass gasification, pyrolysis or torrefaction plants, to gain a better comprehension of the basics of biomass conversion. The author provides many worked out design problems, step-by-step design procedures and real data on commercially operating systems. With a dedicated focus on the design, analysis, and operational aspects of biomass gasification, pyrolysis, and torrefaction, Biomass Gasification, Pyrolysis and Torrefaction, Second Edition offers comprehensive coverage of biomass in its gas, liquid, and solid states in a single easy-to-access source. Contains new and updated step-by-step process flow diagrams, design data and conversion charts, and numerical examples with solutions Includes chapters dedicated to evolving torrefaction technologies, practicing option of biomass cofiring, and biomass conversion economics Expanded coverage of syngas and other Fischer-Tropsch alternatives Spotlights advanced processes such as supercritical water gasification and torrefaction of biomass Provides available research results in an easy-to-use design methodology

Download or read book The Resource Utilization of Plastic Waste with Supercritical Water Treatment written by Hui Jin and published by Elsevier. This book was released on 2022-11-29 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Resource Utilization of Plastic Waste with Supercritical Water Treatment discusses the types of plastic analysis, material characterization, technical principles of supercritical water treatment of waste plastics, the structure and process of the experimental platform, the selection of process parameters, and the establishment of kinetic models in professional areas of the field. Provides a clear understanding of the basic principles and processes of supercritical water treatment of waste plastics technology Enables the reader to develop a complete understanding of the experimental methods of supercritical water gasification plastics, liquefied plastics and collaborative treatments of pollutants Provides an overview of kinetic models, along with the accuracy of modeling results by comparing with experimental results

Download or read book Biomass Gasification and Pyrolysis written by Prabir Basu and published by Academic Press. This book was released on 2010-07-19 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers comprehensive coverage of the design, analysis, and operational aspects of biomass gasification, the key technology enabling the production of biofuels from all viable sources--some examples being sugar cane and switchgrass. This versatile resource not only explains the basic principles of energy conversion systems, but also provides valuable insight into the design of biomass gasifiers. The author provides many worked out design problems, step-by-step design procedures and real data on commercially operating systems. After fossil fuels, biomass is the most widely used fuel in the world. Biomass resources show a considerable potential in the long term if residues are properly handled and dedicated energy crops are grown. Includes step-by-step design procedures and case studies for Biomass GasificationProvides worked process flow diagrams for gasifier design. Covers integration with other technologies (e.g. gas turbine, engine, fuel cells)

Download or read book Handbook of Biomass Valorization for Industrial Applications written by Shahid ul-Islam and published by John Wiley & Sons. This book was released on 2022-01-05 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: HANDBOOK of BIOMASS VALORIZATION for INDUSTRIAL APPLICATIONS The handbook provides a comprehensive view of cutting-edge research on biomass valorization, from advanced fabrication methodologies through useful derived materials, to current and potential application sectors. Industrial sectors, such as food, textiles, petrochemicals and pharmaceuticals, generate massive amounts of waste each year, the disposal of which has become a major issue worldwide. As a result, implementing a circular economy that employs sustainable practices in waste management is critical for any industry. Moreover, fossil fuels, which are the primary sources of fuel in the transportation sector, are also being rapidly depleted at an alarming rate. Therefore, to combat these global issues without increasing our carbon footprint, we must look for renewable resources to produce chemicals and biomaterials. In that context, agricultural waste materials are gaining popularity as cost-effective and abundantly available alternatives to fossil resources for the production of a variety of value-added products, including renewable fuels, fuel components, and fuel additives. Handbook of Biomass Valorization for Industrial Applications investigates current and emerging feedstocks, as well as provides in-depth technical information on advanced catalytic processes and technologies that enable the development of all possible alternative energy sources. The 22 chapters of this book comprehensively cover the valorization of agricultural wastes and their various uses in value-added applications like energy, biofuels, fertilizers, and wastewater treatment. Audience The book is intended for a very broad audience working in the fields of materials sciences, chemical engineering, nanotechnology, energy, environment, chemistry, etc. This book will be an invaluable reference source for the libraries in universities and industrial institutions, government and independent institutes, individual research groups, and scientists working in the field of valorization of biomass.

Download or read book Supercritical Fluid Extraction written by Mark McHugh and published by Elsevier. This book was released on 2013-10-22 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supercritical Fluid Extraction is a technique in which CO2 is used under extremely high pressure to separate solution (e.g., removing caffeine from coffee). Separations is basic to all process industries and supercritical fluid extraction is a specific type which is receiving a high level of attention. The book will combine basic fundamentals with industrial applications. The second edition has been expanded and updated and includes new chapters on chromatography and food processing. "...this is an excellent book which is both instructive and amusing to read. Its true value is neatly summarised in one of the closing sentences: 'We have supplied you with the guidelines and criteria which you can now apply when considering supercritical fluids for your own needs.'' - Chemistry in Britain, February 1995

Download or read book Chemical Catalysts for Biomass Upgrading written by Mark Crocker and published by John Wiley & Sons. This book was released on 2020-03-09 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference to the use of innovative catalysts and processes to turn biomass into value-added chemicals Chemical Catalysts for Biomass Upgrading offers detailed descriptions of catalysts and catalytic processes employed in the synthesis of chemicals and fuels from the most abundant and important biomass types. The contributors?noted experts on the topic?focus on the application of catalysts to the pyrolysis of whole biomass and to the upgrading of bio-oils. The authors discuss catalytic approaches to the processing of biomass-derived oxygenates, as exemplified by sugars, via reactions such as reforming, hydrogenation, oxidation, and condensation reactions. Additionally, the book provides an overview of catalysts for lignin valorization via oxidative and reductive methods and considers the conversion of fats and oils to fuels and terminal olefins by means of esterification/transesterification, hydrodeoxygenation, and decarboxylation/decarbonylation processes. The authors also provide an overview of conversion processes based on terpenes and chitin, two emerging feedstocks with a rich chemistry, and summarize some of the emerging trends in the field. This important book: -Provides a comprehensive review of innovative catalysts, catalytic processes, and catalyst design -Offers a guide to one of the most promising ways to find useful alternatives for fossil fuel resources -Includes information on the most abundant and important types of biomass feedstocks -Examines fields such as catalytic cracking, pyrolysis, depolymerization, and many more Written for catalytic chemists, process engineers, environmental chemists, bioengineers, organic chemists, and polymer chemists, Chemical Catalysts for Biomass Upgrading presents deep insights on the most important aspects of biomass upgrading and their various types.