Download or read book Computational Fluid Dynamics Simulations of Oxy coal Combustion for Carbon Capture at Atmospheric and Elevated Pressures written by Lei Chen (Ph. D.) and published by . This book was released on 2013 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxy-fuel combustion of solid fuels, often performed in a mixture of oxygen and wet or dry recycled carbon dioxide, has gained significant interest in the last two decades as one of the leading carbon capture technologies in power generation. The new combustion characteristics in a high-O2 environment raise challenges for furnace design and operation, and should be modeled appropriately in CFD simulation. Based on a comprehensive literature review of the state-of-the-art research on the fundamentals of oxy-coal combustion, sub-models for the critical physical processes, such as radiation and char combustion, have been properly modified for the O2-rich environment, and the overall performance of CFD simulation on oxy-coal combustion has been validated using Large-Eddy Simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) approaches. The predicted distributions on velocity, species, and temperature were compared with experimental results from the literature in order to validate the CFD simulation. Results show that although agreeing reasonably with the measured mean axial and tangential velocity, all the RANS turbulence models used in this study underestimate the internal recirculation zone size and the turbulence mixing intensity in the char combustion zone, while LES improves the predictions of internal recirculation zone size, the entrainment of oxygen from the staging stream, and the overall flame length than the RANS approaches. Special attention was given to the CO2's chemical effects on CO formation in oxy-fuel combustion, and its modeling approaches in CFD simulations. Detailed reaction mechanism (GRI-Mech 3.0) identifies that the reaction H+CO2 -->/

Download or read book Studies in Advanced Oxy combustion Technologies written by Fei Xia and published by . This book was released on 2014 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2013, approximately 87 percent of the total world energy came from combustion sources. While combustion is of critical significance, it poses serious issues. The rapid increase in energy consumption, primarily from increased fossil fuel use, has raised strong concerns over the current energy infrastructure, the emissions of particulate matter, CO, SO2, and NOx, as well as global warming due to the emission of CO2. Improving combustion efficiency and reducing combustion emissions are essential. This dissertation focuses on two areas: (1) Computational fluid dynamics simulations of a novel burner design for a new oxy-fuel technology with relatively high efficiency and low emissions, and (2) numerical studies of flame structure and soot inception, interpreted in the carbon-to-oxygen atom ratio space for laminar diffusion flames. Part I. Oxy-fuel combustion is considered a promising technology for carbon capture, utilization, and storage (CCUS). One of the primary limitations on full-scale implementation of this technology is the significant increase in the cost of electricity due to a large reduction in plant efficiency and high capital costs. The fact that the CO2 captured must ultimately be pressurized for geo-sequestration or Enhanced Oil Recovery (EOR) enables pressurized oxy-combustion to be implemented at no net pumping cost because the energy to pump oxygen is comparable to that to pump CO2. At higher pressure the latent heat of condensation of the moisture in the flue gas can be utilized in the Rankine cycle, increasing the plant efficiency. A new pressurized oxy-combustion technology, namely staged, pressurized oxy-combustion (SPOC) has been developed in which the flue gas recycle is minimized by means of fuel-staged combustion. As determined through ASPEN Plus modeling, this process increases the net plant efficiency by more than 5 percentage points, compared to first-generation oxy-combustion plants. In the SPOC process, pulverized coal is combusted at high-pressure with negligible recycle. A unique burner and boiler have been designed via computational fluid dynamics (CFD) to effectively and safely burn coal under SPOC conditions. CFD is used to model the process and to determine the effects of operating conditions on the radiative and convective heat transfer in the boiler. It is shown through the simulations that a manageable wall heat flux can be achieved even with very high local gas temperatures. The system is also designed to minimize particle deposition to avoid slagging, fouling, and corrosion, and simulations of ash deposition indicate negligible deposition on the furnace wall. Radiation behavior is also studied to demonstrate radiative trapping effects. It is demonstrated, through both analytical and numerical studies, that the system pressurize is a critical tool to obtain an optically thick medium capable of trapping heat inside the furnace. It is further shown that for a sufficiently large optical thickness radiative trapping can occur, and this, combined with the diffusive-convective profiles of the temperature and absorption coefficient, allow us manage the wall heat flux. An average-temperature method is developed to approximate the heat flux and to study the dynamic relations of temperature and the absorption coefficient. The effects of ash particle size on radiative trapping are systematically studied. It is concluded that the wall heat flux is controlled by particle size as well as particle number concentration, in other words, by particle porosity and fragmentation. Ultimately, burners and boilers are designed to minimize the boiler heat transfer surface area, ash deposition, and fire-side corrosion for the SPOC system. Part II. Understanding the structure of diffusion flames is often complicated by the dependence of flame structure on the boundary conditions, such as composition, temperature, and flow field (e.g., strain rate in a counterflow flame.) The utility of interpreting flame results in the carbon-to-oxygen atom ratio (C/O ratio) space, as opposed to physical space or mixture fraction space, is evaluated. Flame and soot zone structures of counterflow diffusion flames are studied for C2H4 and C3H8 and interpreted in C/O ratio space as a function of the stoichiometric mixture fraction (Zst). The Burke-Schumann results expressed in C/O ratio space demonstrate how a clear and direct understanding of how structure is affected by Zst can be realized. In C/O ratio space, unlike physical or mixture fraction space, the flame location is independent of the stoichiometric mixture fraction. Numerical results with detailed chemical kinetics also indicate that C/O ratio space is a fundamental variable in the sense that, for a given fuel, the location of the flame zones and critical reactions is invariant with Zst and strain rate. Two zones are clearly observed, the radical pool zone and the soot precursor zone which is located on the fuel side of the flame. The onset threshold of soot precursors (C6H5 and C6H6) on the high temperature side of the soot precursor zone is characterized by the depletion of radicals. The role of the hydrogen radical in flame structure and soot inception is demonstrated by studying its production and consumption channels in C/O ratio space, as are the roles of C2H2 in soot precursor depletion and boundary coincidence. The kinetic ratio is used to study the characteristics of key chemical reactions and to identify regions of equilibrium for these reactions. Finally, a modified C/O ratio ((C/O)*) is given to interpret the physical meaning of C/O ratio. The numerical results in this work indicate and explain the advantages of applying C/O ratio space in the analysis of flame structure and soot precursor chemistry.

Download or read book Energy Conversion Engineering written by Ahmed F. Ghoniem and published by Cambridge University Press. This book was released on 2021-11-11 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover the fundamentals and tools needed to model, design, and build efficient, clean low-carbon energy systems with this unique textbook.

Download or read book Simulation and Techno economic Analysis of Pressurized Oxy fuel Combustion of Petroleum Coke written by Hachem Hamadeh and published by . This book was released on 2018 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research presented in this thesis was part of the International Partnership for Carbon Neutral Combustion, which was sponsored by King Abdulla University of Science and Technology. The thesis focuses on oxy-fuel combustion under pressurized conditions and assesses the technical and economic viability of combusting petroleum coke (petcoke) for electricity generation, while capturing CO2. The technical evaluation was conducted through simulating, in Aspen PlusTM, an oxy-combustion power plant that uses petcoke as fuel. The basis for all simulations was a constant heat input of 1877 MWth, while a 3% (on dry basis) excess oxygen was maintain in the flue gas along with an adiabatic flame-temperature of 1866ʻC. Comparisons with the oxy-combustion of Illinois No. 6 coal showed that oxy-coal combustion was 0.6% points (on HHV basis) more efficient than oxy-petcoke combustion (29.0% versus 29.6%). However, operating oxy-petcoke combustion at elevated pressures improved the net efficiency to a maximum of just over 29.8% (on HHV basis) at 10 bar. A sensitivity analysis on the impact of operating pressure was conducted on the fuel intake, O2 required, recycle ratio and removal ratio of SOx and NOx via flash distillation; along with how the operating pressure within the carbon capture unit affects the recovery and purity of the CO2 being separated. The sensitivity analysis showed that pressure had minimal impact on the fuel intake and O2 required but affected recycle ratio by up to 3% points, while increasing pressure improved the removal ratio of SOx and NOx. As for the operating pressure of the carbon capture unit, the recovery and purity of the CO2 produced was preferred at 35 bar. In addition, a modification to the steam cycle is presented that utilizes the latent heat of the flue gas to heat the feed water, which improves the net efficiency of the power plant at all pressures by 1.9% points. As for the economic evaluation, the oxy-petcoke combustion power plant was assumed to be built in the US and in KSA. The levelized cost of electricity (LCOE) for oxy-coal combustion was 11.6 [cent]/kWh (in 2017 USD) compared to 10.4 [cent]/kWh and 6.5 [cent]/kWh for atmospheric oxy-petcoke combustion in the US and in KSA, respectively. The LCOE further drops to a minimum of 9.2 [cent]/kWh in the US, or 5.7[cent]/kWh in KSA, when oxy-petcoke combustion takes place at 10 or 15 bar. However, based on a profitability analysis, operating at 10 bar has the highest net profit, highest net present value and lowest discounted payback period, compared to the plants operating at 1, 5 and 15 bar, whether in the US or in KSA. A sensitivity analysis was also conducted that showed that the cost of manufacturing (COM), LCOE and costs of CO2 avoided and CO2 capture are most sensitive to total capital cost, and to a lesser extent the cost of the fuel, which in this case is petcoke. Overall, the technical and economic evaluation help conclude that using petcoke as a fuel to generate electricity is viable in oil-refining countries like the US or KSA, in which pressurized oxy-petcoke combustion is better than atmospheric as the highest net efficiency and lowest LCOE are achieved at an operating pressure of 10 bar.

Download or read book Temperature Trends in Coal Char Combustion Under Oxy fuel Conditions for the Determination of Kinetics written by and published by . This book was released on 2014 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Formation and Removal of SOx and NOx in Pressurized Oxy fuel Coal Combustion written by Muhammad Jahangir Malik and published by . This book was released on 2019 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growing concerns over greenhouse gas emissions have driven extensive research in carbon capture, storage and sequestration. Oxy-fuel combustion is a promising technology in CO2 capture, as the combustion products consists primarily of CO2 and H2O with contaminants like NOx and SOx. More recently, oxy-fuel combustion under pressurized conditions has gained attention due to its overall higher net efficiency, while decreasing the auxiliary power consumption in the process. The need for a better understanding of the coal combustion in oxy-fuel conditions under elevated pressures and the formation of SOx and NOx in such conditions inspired this research project. In this thesis, the effect of pressurized oxy-fuel combustion on SOx and NOx formation from coal combustion and their removal from the flue gas was investigated. The combustion modelling for lignite coal was conducted in ANSYS Fluent, under oxy-fuel environment at atmospheric pressure and elevated pressures (5 atm, 10 atm, 15 atm). The results showed an increase in SO3 formation and rapid decrease in NO in the flue gas as the pressure was increased in the combustor. At 15 atm, the NOx emissions were found to be below 100 ppm, which is an acceptable concentration of NOx for CO2 transport and storage. In order to investigate the influence of pressure on SOx and NOx in the flue gas in the post-combustion zone, the system was subjected to a temperature profile representative of an actual plant boiler, where the residence time is around 2 seconds. The results showed that the rate of SO2 and NO oxidation to SO3 and NO2, respectively, were influenced by the rate of temperature decrease, and the effect of pressure was not as significant. It was observed that flue gas composition remained constant below 550 K, as all SO3 present in the flue gas converted to gaseous H2SO4. Lastly, simulations for SOx and NOx removal from flue gas via absorption were performed at 15 atm to purify the flue gas to meet the requirements for CO2 transportation. The results showed complete removal of SOx in the form of H2SO4 and SO42- and around 30% NOx removal, mostly in the form of HNO3. A sensitivity analysis was performed on the reflux ratio of liquid in the absorber and the results showed increased NOx removal at lower reflux ratio. The investigation helped conclude that pressurized oxy-fuel combustion results in lower SOx and NOx emissions, and require less sophisticated separation techniques to meet the pipeline threshold for CO2 transportation in storage and sequestration.

Download or read book Numerical and Experimental Investigation of the Oxy coal Combustion in Carbon Capture Technologies written by Maryam Gharebaghi and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oxy Fuel Combustion for Power Generation and Carbon Dioxide CO2 Capture written by L Zheng and published by Elsevier. This book was released on 2011-02-26 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxy-fuel combustion is currently considered to be one of the major technologies for carbon dioxide (CO2) capture in power plants. The advantages of using oxygen (O2) instead of air for combustion include a CO2-enriched flue gas that is ready for sequestration following purification and low NOx emissions. This simple and elegant technology has attracted considerable attention since the late 1990s, rapidly developing from pilot-scale testing to industrial demonstration. Challenges remain, as O2 supply and CO2 capture create significant energy penalties that must be reduced through overall system optimisation and the development of new processes.Oxy-fuel combustion for power generation and carbon dioxide (CO2) capture comprehensively reviews the fundamental principles and development of oxy-fuel combustion in fossil-fuel fired utility boilers. Following a foreword by Professor János M. Beér, the book opens with an overview of oxy-fuel combustion technology and its role in a carbon-constrained environment. Part one introduces oxy-fuel combustion further, with a chapter comparing the economics of oxy-fuel vs. post-/pre-combustion CO2 capture, followed by chapters on plant operation, industrial scale demonstrations, and circulating fluidized bed combustion. Part two critically reviews oxy-fuel combustion fundamentals, such as ignition and flame stability, burner design, emissions and heat transfer characteristics, concluding with chapters on O2 production and CO2 compression and purification technologies. Finally, part three explores advanced concepts and developments, such as near-zero flue gas recycle and high-pressure systems, as well as chemical looping combustion and utilisation of gaseous fuel.With its distinguished editor and internationally renowned contributors, Oxy-fuel combustion for power generation and carbon dioxide (CO2) capture provides a rich resource for power plant designers, operators, and engineers, as well as academics and researchers in the field. - Comprehensively reviews the fundamental principles and development of oxy-fuel combustion in fossil-fuel fired utility boilers - Provides an overview of oxy-fuel combustion technology and its role in a carbon-constrained environment - Introduces oxy-fuel combustion comparing the economics of oxy-fuel vs. post-/pre-combustion CO2 capture

Download or read book Advanced Combustion Technologies for Low Carbon Emissions written by Jun Li and published by Frontiers Media SA. This book was released on 2023-07-10 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermofluid Modeling for Energy Efficiency Applications written by Mohammad Masud Kamal Khan and published by Academic Press. This book was released on 2015-09-01 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermofluid Modeling for Sustainable Energy Applications provides a collection of the most recent, cutting-edge developments in the application of fluid mechanics modeling to energy systems and energy efficient technology. Each chapter introduces relevant theories alongside detailed, real-life case studies that demonstrate the value of thermofluid modeling and simulation as an integral part of the engineering process. Research problems and modeling solutions across a range of energy efficiency scenarios are presented by experts, helping users build a sustainable engineering knowledge base. The text offers novel examples of the use of computation fluid dynamics in relation to hot topics, including passive air cooling and thermal storage. It is a valuable resource for academics, engineers, and students undertaking research in thermal engineering. - Includes contributions from experts in energy efficiency modeling across a range of engineering fields - Places thermofluid modeling and simulation at the center of engineering design and development, with theory supported by detailed, real-life case studies - Features hot topics in energy and sustainability engineering, including thermal storage and passive air cooling - Provides a valuable resource for academics, engineers, and students undertaking research in thermal engineering

Download or read book Combustion of Pulverised Coal in a Mixture of Oxygen and Recycled Flue Gas written by Dobrin Toporov and published by Elsevier. This book was released on 2014-05-30 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion of Pulverised Coal in a Mixture of Oxygen and Recycled Flue Gas focuses on a niche technology, combustion of coal in an oxygen rich environment, which is one approach to obtaining 'clean coal,' by making it easier to capture carbon that is released in the combustion process. Toporov's book breaks ground on covering the key fundamentals of oxycoal technologies, which have not yet been covered in this depth. Combustion of Pulverised Coal in a Mixture of Oxygen and Recycled Flue Gas summarizes the main results from a pioneering work on experimental and numerical investigations of oxyfuel technologies. It provides the theoretical background of the process, the problems to be faced, and the technical solutions that were achieved during these investigations. - Summarizes results from investigations of oxyfuel technologies performed at Aachen University, Germany - Provides theoretical background, as well as the primary problems of these technologies and how they can be solved

Download or read book Pulverized Coal Combustion and Gasification written by L. Smoot and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: viii and approaches could be adapted to other coal conversion and combustion problems, we have not considered combustion or gasification in fluidized or fixed beds or in situ processes. In addition, we have not considered other fossil-fuel combustion problems associated with oil shale, tar sands, etc., even though many aspects of pulverized-coal combustion would relate to these problems. For the case of pulverized-coal models, we have attempted to provide a detailed description of the model foundations. Parts I and II of this book emphasize general principles for describing reacting, turbulent or laminar, multiphase systems. General conservation equations are developed and summarized. The basis for computing thermochemical equilibrium in complex, heterogeneous mixtures is presented, together with techniques for rapid computation and reference to required input data. Rate processes are then discussed, including pertinent aspects of turbulence, chemical kinetics, radiative heat transfer, and gas-particle convective-diffusive interactions. Much of Part II deals with parameters and coefficients for describing these complex rate processes. This part of the book provides recommended values of coefficients and parameters for treating complex reacting flows. Parts I and II may well be suitable for use in an advanced course in reacting flows, and have been written partly with that in mind. Part III deals with more specific aspects of pulverized-coal characteristics and rate processes. Following a general description of coal structure and constitution, coal pyrolysis and char oxidation processes are considered.

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 Coal Energy Conversion Integrated with Deep Saline Aquifer Carbon Storage Via Combustion in Supercritical Water written by John Russell Heberle and published by Stanford University. This book was released on 2011 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon capture and sequestration (CCS) technologies aim to allow the continued use of fossil fuels by outputting carbon in a form other than atmospheric CO2. Several types of geologic reservoirs are considered as alternatives; of these, deep saline aquifers have the largest potential storage capacity worldwide. Unfortunately, neat CO2 injected into an aquifer is less dense than the native brine. The resulting buoyancy presents a potential for leakage from the storage formation, and, ultimately, to the atmosphere. This work describes a method for using coal to produce electricity that creates a pre-equilibrated brine/CO2 solution for injection into a saline aquifer. Such solutions are more dense than the original brine, and present no potential for buoyancy-driven leakage. A concept is introduced in which coal is oxidized in high-pressure, high-temperature water drawn from a saline aquifer in a process known as supercritical water oxidation (SCWO). Combustion in supercritical water and subsequent aquifer storage of all coal-derived fluid effluent removes the need for CO2 separation and compression steps common in other coal-fired designs with CCS. The properties of supercritical water (T > 647 K, P > 221 bar) are described that make it a suitable combustion medium---in contrast to water at ambient conditions. A conceptual plant is developed that includes systems to manage brine and coal (a solid, complex fuel). The system uses a heat engine for work extraction from hot combustion products, and so may be called a supercritical water oxidation, indirectly-fired combined cycle, or SCWO/IFCC. Next, a thermodynamic model is developed to evaluate the performance of this plant and compare it to other coal-fired designs with CCS. Next, a laboratory-scale combustor, constructed to study flames in supercritical water, is described. This apparatus follows from previous supercritical water reactors that were built to study the destruction of hazardous wastes, but is targeted toward the development of a combustor suitable for use in a power plant. Challenges encountered operating systems that are simultaneously high-pressure and high-temperature are discussed, including the use of several types of metal seals. Autoignition results from initial combustion experiments are presented and compared to previous work.

Download or read book Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide CO2 Capture written by Paul Fennell and published by Elsevier. This book was released on 2015-05-21 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to chemical looping and combustion. Chapters review the market development, economics, and deployment of these systems, also providing detailed information on the variety of materials and processes that will help to shape the future of CO2 capture ready power plants. - Reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to calcium and chemical looping - Provides a lucid explanation of advanced concepts and developments in calcium and chemical looping, high pressure systems, and alternative CO2 carriers - Presents information on the market development, economics, and deployment of these systems

Download or read book Coal Combustion and Gasification written by L.Douglas Smoot and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of coal is required to help satisfy the world's energy needs. Yet coal is a difficult fossil fuel to consume efficiently and cleanly. We believe that its clean and efficient use can be increased through improved technology based on a thorough understanding of fundamental physical and chemical processes that occur during consumption. The principal objective of this book is to provide a current summary of this technology. The past technology for describing and analyzing coal furnaces and combus tors has relied largely on empirical inputs for the complex flow and chemical reactions that occur while more formally treating the heat-transfer effects. GrOWing concern over control of combustion-generated air pollutants revealed a lack of understanding of the relevant fundamental physical and chemical mechanisms. Recent technical advances in computer speed and storage capacity, and in numerical prediction of recirculating turbulent flows, two-phase flows, and flows with chemical reaction have opened new opportunities for describing and modeling such complex combustion systems in greater detail. We believe that most of the requisite component models to permit a more fundamental description of coal combustion processes are available. At the same time there is worldwide interest in the use of coal, and progress in modeling of coal reaction processes has been steady.

Download or read book Fuel Residence Times for Clean Combustion of Coal in a Pressurized Fluidized Bed Cold Flow Study written by Marc-André Séguin and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic Climate Change is amongst the greatest challenges of human civilization. A key area that will play a large role in mitigating its effects are clean fossil fuel applications. Clean coal combustion is one such application with an urgent timeline. This can be achieved with an oxygen-fired pressurized fluidized bed combustor with downstream carbon capture and sequestration. In relation to pressurized fluidization processes, understanding the influence of pressure on bed hydrodynamics and in turn their effect on parameters including fuel residence time is essential. For the proposed combustor, the heat exchanger boiler tubes are submerged in the fluidized bed such that the effect of a horizontal tube bank on the fuel residence time is also of great importance. The main focus of present work was to evaluate the impact of gas velocity, pressure, presence of a tube bank and fuel feed rate on the average fuel residence time. Experiments were conducted under cold flow conditions in a pilot-scale pressurized fluidized bed with an inner diameter of 0.15 m. The fluidization material was relatively large glass beads (1.0 mm in diameter) while the fuel particles were simulated with smaller glass beads (40 to 138 ?m in diameter), susceptible to entrainment. Operating pressures and superficial gas velocities tested were between 101.3 and 1200 kPa and 0.4 and 1.1 m/s respectively. To simulate coal combustors, experiments were then conducted in a continuous mode where the fuel particles were continuously fed to the fluidized bed of large particles over a desired period of time. Downstream, entrained particles were continuously captured to determine the entrainment rate and mass of fuel particles inside the fluidized bed at steady state, which yielded the average fuel residence time. The combination of elevated pressure with the tube bank present was found to enhance gas bubble break up and reduce the average gas bubble size. In turn, this increased the average fuel residence time of 83 ?m particles by nearly 3 fold to a value of 77 s in comparison to 27 s at atmospheric pressure. The effect of gas velocity was not found to be statistically significant under the range tested. Similarly the effect of increased fuel feed rate by 50% neither had a statistically significant impact.