Download or read book Gasification Kinetics and Pore Development of a Highveld Coal Char at High Pressures written by S. F. Conradie and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Final year report -- Chemical and Minerals Engineering.
Download or read book Evaluation of Coal Char Gasification Kinetics and Pore Development in High Pressure Steam and Carbon Dioxide written by and published by . This book was released on 2020 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: High pressure steam and CO2 gasification kinetics -- Intrinsic reaction rates -- Pore development -- Highveld coal char.
Download or read book The Influence of Carbon Dioxide on the Gasification Rate of Highveld Coal Chars at Elevated Pressures written by and published by . This book was released on 2018 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 gasification -- Elevated pressure -- Highveld coal char -- Pore development.
Download or read book Kinetics of Coal Gasification written by James L. Johnson and published by John Wiley & Sons. This book was released on 1979-12-20 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides the best description of coal gasification reactions available today, presenting a series of publications by the late James Lee Johnson that trace his work on the development of coal gasification kinetics. Puts gasification kinetics into perspective for reactor design by discussing gasification thermodynamics, fluidized beds, and the physical characteristics of coals and coal chars for estimating this gasification reactivity. An outstanding reference based on a chaper contributed by Dr. Johnson to CHEMISTRY OF COAL UTILIZATION SUPPLEMENTARY VOLUME 2 (edited by Martin A. Elliot).
Download or read book Carbon Dioxide Gasification Kinetics of a Highveld Coal at Elevated Pressures written by J. S. Pienaar and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Final year project report -- Chemical Engineering.
Download or read book Kinetics of Gasification of Coal Chars at High Pressure written by Stuart Maxwell and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Characteristics and CO2 Reactivity of Partially Gasified Pittsburgh No 8 Coal Chars Generated in a High pressure High temperature Flow Reactor written by Vijayaragavan Krishnamoorthy and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrated gasification combined cycle (IGCC) is an advanced power generation technology based on gasification of coal or solid fuels. Despite many commercial operations, the knowledge of char gasification rates at high pressures and temperatures, crucial to the design and troubleshooting of the gasifiers, are relatively unknown. While many kinetic studies have been performed at atmospheric pressure and low heating rates, there are few studies that examined the reactivity of chars generated at high temperatures and elevated pressuresGasification rate of chars in entrained-flow gasifiers is dependent on both intrinsic reactivity and the gas diffusion rate of reactants into pores. Therefore, the knowledge of intrinsic reaction rate and the structural features of the char are necessary for developing a kinetic model. The aim of the thesis is to determine the intrinsic reactivity and the structural features of the chars generated at elevated pressures and temperatures pertinent to conditions of the entrained-flow gasifiers. A series of interrelated studies were conducted to characterize the gasification behavior of a widely used Pittsburgh No,8 coal. To generate chars under conditions similar to that of the gasifier, a 20 kW high-pressure, high-temperature flow reactor (HPHTFR) was designed to operate up to 1650C and 30 bar. The chars obtained at various temperatures, pressures, and pyrolysis atmospheres were characterized for physical and chemical structure using surface area analyzer, XRD, Raman, and morphological analysis. The CO2 kinetics on chars were obtained using a high pressure thermogravimetric analyzer (HPTGA). The structural properties and intrinsic kinetics of chars widely reported in the literature were generated in inert atmospheres. However, the pyrolysis of feedstock occurs in the presence of reaction gas. This difference can affect char structural properties and intrinsic reactivity. To determine the role of pyrolysis atmosphere, chars were generated in three different atomspheres-CO2/N2, Ar and N2- at 1100C and 6.2 bar. The chars generated in the CO2/N2 atmosphere showed higher conversion compared to that of chars generated in N2 and Ar atmospheres. The increased conversion in the CO2/N2 atmosphere was attributed to increased gasification of tar/soot. While the volatile yield showed some difference, char properties such as surface area, swelling ratio, defects to graphitic band ratio and crystallite sizes showed no difference. The kinetic parameters of the chars were obtained using the nth order model. The activation energy was found to be independent of pyrolysis atmospheres. The order of reaction was found to be significantly affected by the pyrolysis atmosphere. The order of reaction followed the trend: CO2/N2> N2 Ar. The order of the reaction was found to correlate with surface area evolution.Gasification of coal can be impacted by the organic and inorganic compositional heterogeneity, which further impact the char morphology, and the intrinsic reactivity. To account for the compositional heterogeneity, chars were generated from various size fractions (-106+75, -150+106, -212+150, -420+212 m at 1300C and 11.3 bar) and density fractions (1.3 g/cc, 1.3-1.6 g/cc, 1.6g/cc of -106+75 m at 1300C and 11.3 bar). Chars were also generated over a range of temperatures (1100, 1300, and 1400C at 11.3 bar for the -150+106 m fraction), pressures (3.4, 6.2, 11.3, 15.5, and 21.7 bar at 1300C for -150+106 m fraction) to study the effect of temperature and pressure on char structures and reactivity. Chars were characterized for morphology, pore structure (i.e. surface area and pore volume), reflectance, and reactivity using oil immersion microscopy, N2 adsorption technique, reflectance microscopy, and thermogravimetric analyzer, respectively. The swelling ratio, pore volume, and surface area increased up to certain pressure while these parameters decreased with particle size and density fraction. The intrinsic reactivity of chars increased with inorganic matter and feed particle size, while it decreased with increase in char generation temperature. The intrinsic gasification rate is an important parameter for designing a kinetic model. Chars were obtained by partially gasifying Pittsburgh No.8 coal in CO2 atmosphere at 1300C and over a range of pressures (3.4, 6.2, 11.3, 15.5, and 21.7 bar) in the HPHTFR. The intrinsic reaction rate of those chars with CO2 was obtained at the char generation pressure using the HPTGA. The kinetic parameters were obtained using the nth order model. The intrinsic reaction rate, and activation energy were found to be independent of the char generation pressure. The order of reaction was obtained by varying CO2 partial pressures. The order of reaction decreased with increase in char generation pressure. The comparison of initial char with the char obtained at ~20% conversion in the HPTGA for surface area and pore volume showed that the reaction primarily occurs in microporous regions. The order of reaction also closely followed the surface area during gasification in the HPTGA.Through this research, a comprehensive assessment of the entrained-flow gasification behavior of Pittsburgh No.8 coal has been performed using proven experimental techniques under conditions of industrial interest. The structural features and kinetics were obtained. The generated data provide optimum, and trends that can be used as direct inputs to kinetic modelling and gasifier design applications.
Download or read book Investigation of High temperature and High pressure Steam Gasification Kinetics of a Coal derived Char Surrogate written by Madison A. Kelley and published by . This book was released on 2017 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Steam Partial Pressure on Coal Char Gasification of Highveld Coal written by P. P. Maré and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Final year report -- Chemical and Minerals Engineering.
Download or read book Carbon and Coal Gasification written by J.L. Figueiredo and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 649 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon gasification reactions form the basis of many important industrial processes, such as the combustion of coal and the produc tion of synthesis gas, fuel gases and activated carbons. They are also involved in metallurgical processes and in the regeneration of coked catalysts. Thus, understanding the fundamentals of carbon gasification is of vital importance for further technological development. Moreover, the subject is of interdisciplinary nature, involving chemistry, ma terials science and chemical engineering. Therefore, it was thought that an Advanced Study Institute would be fruitful in establishing the state of the art, in bringing together experts from the various sectors involved and in identifying areas of required research and industrial development. Such a meeting was held at Alvor, Portugal, from the 20th to the 31st May 1985, and the lectures presented the reof are collected in this volume. The present volume is organized in seven chapters. The Intro duction presents the carbon gasification reactions an~ their rele vance for particular processes and industrial uses. In the second chapter, the structures of carbon and coal are reviewed, together with methods of structural, chemical and textural characterization.
Download or read book Coal Gasification Existing Processes New Developments written by Hans-Dieter Schilling and published by Springer. This book was released on 1981-08 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pressure Carbonization of a High volatile A Bituminous Coal to Produce High BTU Gas written by and published by . This book was released on 1964 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Kinetics of High Temperature Gasification of Highveld Coal written by M. Longland and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Final year report -- Chemiese en Mineraalingenieurswese.
Download or read book Integration of Random Pore Model Langmuir Hinshelwood Kinetics To Study High Temperature Coal Gasification written by Krishnaswami Rajendren and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Random pore model (Bhatia and Perlmutter, 1980; 1981; 1983) has been applied extensively to both char oxidation systems (Su and Perlmutter, 1985) and char gasification systems with CO2 (Bhatia, 1981) and H2O (Chi and Perlmutter, 1989). The model solutions developed in these works assume the reaction to be first order with respect to the reactant gas. But it is well known that coal char systems are highly porous and the gasification reactions follow the Langmuir-Hinshelwood (LH) kinetics (Ergun, 1955).There have been attempts to combine random pore model with LH kinetics for competing CO2 and H2O gasification reactions (Umemoto et. al., 2013). But these efforts are restricted to the low temperature kinetically controlled regime. There is a need to extend the combined model to systems at higher temperature that are pore diffusion controlled to better understand the industrial systems of coal gasification.In this study, we extend the random pore model with transport and diffusion effects and Stefan-Maxwells multi-component diffusion modeling framework to incorporate LH kinetics to CO2 gasification systems with varying amounts of CO. We finally explore the possibility of extending the framework to the combined CO2 and H2O gasification systems in presence of H2O, CO and H2 to syngas synthesis.
Download or read book Brown Coal Char CO2 gasification Kinetics with Respect to the Char Structure Part I Char Structure Development written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT written by and published by . This book was released on 2005 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No. 8 and Illinois No. 6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No. 8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical reaction mechanism for the NBFZ tests.
Download or read book Kinetics of Coal Gasification written by James Lee Johnson and published by . This book was released on 1979 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
