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Oxy-Fuel Combustion for Power Generation and Carbon Dioxide (CO2) Capture

Oxy-Fuel Combustion for Power Generation and Carbon Dioxide (CO2) Capture
A Book

by L Zheng

  • Publisher : Elsevier
  • Release : 2011-02-26
  • Pages : 400
  • ISBN : 0857090984
  • Language : En, Es, Fr & De
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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

Oxy-fuel Combustion

Oxy-fuel Combustion
Fundamentals, Theory and Practice

by Chuguang Zheng,Zhaohui Liu

  • Publisher : Academic Press
  • Release : 2017-09-14
  • Pages : 384
  • ISBN : 0128123222
  • Language : En, Es, Fr & De
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Oxy-fuel Combustion: Fundamentals, Theory and Practice provides a comprehensive review of various aspects of oxy-fuel combustion technology, including its concept, fundamental theory, pilot practice, large-scale feasibility studies and related practical issues, such as the commissioning and operation of an oxy-fuel combustion plant. Oxy-fuel combustion, as the most practical large-scale carbon capture power generation technology, has attracted significant attention in the past two decades. As significant progress has been achieved in worldwide demonstration and the oxy-combustion concept confirmed by Schwartze Pump, CUIDEN, Callide, Ponferrada and Yingcheng projects in the past five years, this book provides a timely addition for discussion and study. Covers oxy-fuel combustion technology Includes concepts, fundamentals, pilots and large-scale feasibility studies Considers related practical issues, such as the commissioning and operation of an oxy-fuel combustion plant Focuses on theories and methods closely related to engineering practice

Oxy-fuel Combustion Study of Biomass Fuels in a 20kWth Fluidized Bed Combustor

Oxy-fuel Combustion Study of Biomass Fuels in a 20kWth Fluidized Bed Combustor
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2018
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Highlights: 3 biomass fuels were tested in a BFB under air and oxy-fuel combustion conditions. Similar temperature profiles found for combustion in air and in 30% O2 /70% CO2 . Lower CO emission found for oxy combustion when O2 in O2 /CO2 mixture is over 25%. Similar NOx emissions found for biomass combustion in air and in 30% O2 /70% CO2 . Freeboard temperature plays a major role influencing both CO and NOx emissions. Abstract: Oxy-fuel combustion is one of the promising carbon capture technologies considered to be suitable for future commercial applications with stationary combustion plants. Although more and more biomass and waste are now being burned in stationary combustion plants, research on oxy-fuel combustion of biomass has received much less attention in comparison to oxy-fuel combustion of coal. In this work, a series of tests was carried out in a 20kWth fluidized bed combustor under oxy-fuel conditions firing two non-woody fuels (miscanthus and straw pellets) and one woody fuel (domestic wood pellet). The effects of the combustion atmosphere (air and oxy-fuel) and oxygen concentration in the oxidant of the oxy-fuel combustion on gas emissions and temperature profiles were systematically studied with the overall excess oxygen coefficient in the combustor being maintained roughly constant throughout the tests. The experimental results showed that replacing the air with an oxy-fuel oxidant of 21vol% O2 and 79vol% CO2 resulted in a significant decrease in combustion temperature and ultimately led to the extinction of the biomass flame due to the larger specific heat of CO2 compared to N2 . To keep a similar temperature profile to that achieved under the air combustion conditions, the oxygen concentration in the oxidant of O2 /CO2 mixture had to be increased to 30vol%. A drastic decrease in CO emissions was observed for all three biomass fuels (up to 80% reduction when firing straw) under oxy-fuel combustion conditions providing that the oxygen concentration in the oxidant of O2 /CO2 mixture was above 25vol%. NOx emissions were found to decrease with the oxygen concentration in the oxy-fuel oxidant, due to i) the increase of bed temperature, which implies more volatile-N released and converted in the dense bed zone and ii) the less dilution of the gases inside the dense bed zone, which leads to a higher CO concentration in this region enhancing the reduction of NOx. Similar NOx emissions to those obtained with air combustion were found when the oxygen concentration in the oxy-fuel oxidant was kept at 30vol%. Further analysis of the experimental results showed that the gas emissions when firing the non-woody fuels were controlled mainly by the freeboard temperature instead of the dense bed region temperature due to the characteristically high volatile matter content and fines of this kind of biomass fuels.

Oxy-fuel Combustion of Estonian Oil Shale: Kinetics and Modeling

Oxy-fuel Combustion of Estonian Oil Shale: Kinetics and Modeling
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2016
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Abstract: In this work, non-isothermal thermal analysis (TA) methods combined with Fourier transform infrared (FTIR) spectroscopy were applied to investigate specifics of different stages of oxy-fuel (OF) combustion of Estonian oil shale (EOS) and its char. Kinetics of EOS and its char oxidation were analyzed in different atmospheres in order to understand the complex mechanism of oil shale (OS) OF combustion. Additionally, the OF combustion of OS in circulating fluidized bed (CFB) was simulated with the recently released Aspen Plus fluidized bed (FB) reactor which treats bottom zone and freeboard hydrodynamics. Particular attention was given to the determination of the required elutriated mass flows to maintain the heat balance of the system for OF combustion cases. Four case studies were simulated including: Case 1: Air combustion, Case 2: 21%O2 /flue gas, Case 3: 23%O2 /flue gas and Case 4: 30%O2 /flue gas. The results of TA experiments show that the pyrolysis behavior is very similar in Ar and CO2 until 500°C and there is no visible char carbon and CO2 reaction under OF conditions. The emissions of CO2 from mineral part of OS can be diminished as decomposition of calcite takes place at higher temperatures in OF combustion. Activation energies calculated for oxidation of OS and its char in CO2 /O2 are notably less than activation energies calculated for Ar/O2 atmosphere. Modeling results show that higher fuel mass flow rate and higher O2 concentration in the oxidizer have to be considered in the set of conditions for OF in order to extract the same amount of heat as in air combustion. The Case 3 with 23% inlet O2 concentration has a similar behavior as compared to air combustion in terms of temperature of the boiler and recirculation rate of the particles. The data obtained from experimental measurements and models is valuable for the possible implementation of OF combustion of EOS in CFB boilers.

Laser-based Investigation of Gas and Solid Fuel Combustion under Oxy-Fuel Atmosphere

Laser-based Investigation of Gas and Solid Fuel Combustion under Oxy-Fuel Atmosphere
Laserbasierte Untersuchung von Feststoff-und Gasverbrennung unter Oxy-Fuel-Atmosphäre

by Sebastian Bürkle

  • Publisher : BoD – Books on Demand
  • Release : 2019-03-04
  • Pages : 188
  • ISBN : 3748145144
  • Language : En, Es, Fr & De
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Oxy-fuel combustion has the potential to reduce the atmospheric CO2-emissions of fossil fuel power plants by burning gaseous or solid fuels under an atmosphere of carbon dioxide and oxygen. The combustion under oxy-fuel operating conditions, however, is accompanied by major changes in the combustion behavior. The underlying chemical and physical processes are complex and highly coupled, which impedes investigations and modeling. Since tactile and most of the optical measurement techniques fail under the sensitive and simultaneously harsh environments of oxy-fuel combustion, an optical in-situ measurement system based on tunable diode laser absorption spectroscopy is developed in this work. This system allows to investigate the thermochemical state of combustion gases with respect to the quantitative concentrations of multiple combustion-relevant gases and the gas temperature. In combination with a newly developed and applied measurement strategy, the system even allows for a measurement of the gas residence time distribution. To improve the measurement accuracy, multiple absorption line parameters are experimentally determined. The measurement system is applied to three oxy-fuel combustion systems. First, the thermochemical state of the laminar, non-premixed methane combustion under oxy-fuel atmosphere is studied. The turbulent, premixed combustion of the same fuel under air and two oxy-fuel atmospheres is studied in a 20 kWth swirled combustor. Measurements of the residence time distribution of fluids in the combustion chamber provide insights into mixing and transport properties of the flow. The thermochemical state reveals insights into the reaction progess and flow mixing. Co-firing of three different solid fuels in an assisting gas flame is investigated for a combined thermal power up to 40 kWth. Here, the char burnout of the particles is investigated. The thermochemical state of the combustion of pure torrefied biomass under air and oxy-fuel combustion atmosphere is investigated in a 60 kWth close-to-application facility and compared to equillibrium calculations.

NO and N2O Emissions in Oxy-fuel Combustion of Coal in a Bubbling Fluidized Bed Combustor

NO and N2O Emissions in Oxy-fuel Combustion of Coal in a Bubbling Fluidized Bed Combustor
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2015
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Highlights: NO and N2 O emissions follow the same trend with temperature under oxy-fuel and air-firing combustion. Higher rank coals generate higher N-coal conversion to NO and N2 O. An increase in the coal moisture content decreases NO emissions and hardly affects N2 O emissions. The presence of Ca-based sorbent affects the NO and N2 O chemistry. The high levels of CO2 seem not to affect the catalytic activity of the sorbent. Abstract: Emissions from coal oxy-fuel combustion are receiving significant attention during the last years. This paper is focused on the analysis of fuel-N emissions in fluidized bed combustion systems. Experiments were carried out in a bubbling fluidized bed unit in the temperature interval 850–950 °C. Different coals (anthracite, bituminous and lignite) were used as fuels and different sorbents were employed for in-bed sulfur retention. In the experiments, NO, N2 O and NO2 were measured. NO2 was not detected in any of the operating conditions. The influence of temperature on NO and N2 O emissions was the same as in conventional combustion: NO emission increased as temperature increased while N2 O emission decreased. Nevertheless, the total fuel-N conversion to nitrogenous species seemed to be lower than in combustion with air. As in air-firing combustion, the highest levels of NO and N2 O were registered with the highest rank coals. The Ca-sorbent was found to have a key role on NO reduction via catalytic reaction and this catalytic effect seemed not to be affected by the high CO2 levels present in oxy-fuel combustion. Also, the moisture content in the coal affected the NO formation, which decreased with an increase in the coal moisture content. A similar effect was observed by increasing the oxygen concentration fed to the combustor.

Online Alkali Measurement During Oxy-fuel Combustion

Online Alkali Measurement During Oxy-fuel Combustion
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2017
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Abstract: Coal has been the main fuel in the generation of heat and power for many years and will continue to be so for years to come. Global warming awareness has led to the Kyoto Protocol, which targets the abatement of six greenhouse gases, including carbon dioxide (CO2 ). For the abatement of CO2 emissions, co-combustion of coal and biomass is an attractive solution. Other mitigation solutions include oxy-fuel combustion followed by Carbon Capture and Storage (CCS). However, co-combustion with coal and biomass in oxy-fuel atmosphere has been found to be conducive to chlorine-induced corrosion, slagging and fouling due to the use of complex fuel mixtures rich in alkali metals and chlorine. In order to address problems such as high-temperature corrosion, slagging and fouling caused by the use of these types of fuel mixtures, an alkali-measuring device is needed. The In-situ Alkali Chloride Monitor (IACM) utilizes UV light and Differential Optical Absorption Spectroscopy to measure gas-phase potassium chloride (KCl). This device has been successfully employed during biomass (wood chips and demolition wood) combustion and waste incineration. To investigate its performance in oxy-fuel combustion, the instrument was mounted on a 100 kW oxy-fuel combustion test unit equipped with a propane burner and a system for seeding of aqueous potassium chloride solution. The unit was operated in air- and oxy-fuel mode and the experiments substantiated the feasibility of online monitoring of gas-phase KCl in the flue gas during oxy-fuel combustion. The employment of an online alkali monitoring device during oxy-fuel combustion has the potential to increase the understanding of the release and capture of alkali chlorides, which in turn opens up for mitigation methods to reduce high temperature corrosion, slagging and fouling. This is a cost-efficient, sustainable solution because it extends the operational time of the boiler, reducing related maintenance costs.

Fireside Corrosion in Oxy-fuel Combustion of Coal

Fireside Corrosion in Oxy-fuel Combustion of Coal
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2012
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Oxy-fuel combustion is burning a fuel in oxygen rather than air. The low nitrogen flue gas that results is relatively easy to capture CO2 from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N2 with CO2 and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe-Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions.

GRH 12-01 Fireside Corrosion in Oxy-fuel Combustion Poster 0108

GRH 12-01 Fireside Corrosion in Oxy-fuel Combustion Poster 0108
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2012
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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The goals are to: (1) Achieve 90% CO2 capture at no more than a 35% increase in levelized cost of electricity of post-combustion capture for new and existing conventional coal-fired power plants; (2) Provide high-temperature corrosion information to aid in materials development and selection for oxy-fuel combustion; and (3) Identify corrosion mechanism and behavior differences between air- and oxy-firing.

Simulation and Techno-economic Analysis of Pressurized Oxy-fuel Combustion of Petroleum Coke

Simulation and Techno-economic Analysis of Pressurized Oxy-fuel Combustion of Petroleum Coke
A Book

by Hachem Hamadeh

  • Publisher : Unknown Publisher
  • Release : 2018
  • Pages : 260
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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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.

Investigation on Flame Characteristics of Oxy-fuel Combustion

Investigation on Flame Characteristics of Oxy-fuel Combustion
A Book

by Md. Rafiqul Islam

  • Publisher : Unknown Publisher
  • Release : 2011
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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The Fate of Mercury in Fluidized Beds Under Oxy-fuel Combustion Conditions

The Fate of Mercury in Fluidized Beds Under Oxy-fuel Combustion Conditions
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2016
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Highlights: Mercury speciation in an oxy-fuel fluidized bed combustor has been analyzed. Sulfated Ca-based sorbent enhances the Hg uptake as particle-bound mercury. The higher SO2 concentration the lower mercury oxidation from Hg 0 to Hg 2+ . NO and H2 O recycled hardly affect mercury speciation at these operating conditions. Abstract: Among the different pollutant gases released from oxy-coal combustion, mercury is the responsible for important operational issues in the CO2 processing unit, being able to cause material corrosion. Some studies concerning the fate of mercury during oxy-coal combustion are referred to pulverized coal (PC) boilers. However, the fate of mercury emissions in fluidized bed (FB) combustors has yet to be elucidated. In this work, mercury emissions from a 3 kWth bubbling FB combustor operating under oxy-fuel combustion conditions have been evaluated. For this purpose, two Spanish Ca-based sorbents and two Spanish coals were used. The effects of type of Ca-based sorbent, the Ca/S molar ratio, temperature and recycled gases (NO, SO2 and H2 O) typical in oxy-fuel combustion process on the distribution of mercury species have been analyzed. It was observed that the presence of Ca-based sorbents in the combustor favored mercury fixation as particle-bound mercury which exhibited a maximum at a temperature about 925 °C corresponding to the highest degree of limestone sulfation. SO2 recirculation inhibited the Hg 0 oxidation and thus the mercury fixation as particle-bound mercury decreased. However, neither NO nor steam recirculation affected mercury speciation.

Numerical Modeling and Simulation of Oxy-Fuel Combustion Processes

Numerical Modeling and Simulation of Oxy-Fuel Combustion Processes
A Book

by Sima Farazi

  • Publisher : Unknown Publisher
  • Release : 2019
  • Pages : 329
  • ISBN : 9783844070323
  • Language : En, Es, Fr & De
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Investigation of Oxy-fuel Combustion Behind Reflected Shock Waves

Investigation of Oxy-fuel Combustion Behind Reflected Shock Waves
A Book

by Owen Marcus Pryor

  • Publisher : Unknown Publisher
  • Release : 2018
  • Pages : 109
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Supercritical carbon dioxide has brought about new questions on the chemical kinetics of several small hydrocarbon fuels and the effects of carbon dioxide as the primary diluent on the different fuels. This report presents work on the ignition delay times and several species time-histories of methane, ethylene and syngas over a range of conditions. All experiments were conducted behind reflected shock waves using two different shock tubes. The ignition delay times were measured using a GaP photodetector to measure the emission of light. The species time-histories were measured using single laser spectroscopy. The effect of CO2 as a diluent on the fluid dynamics of the system were also examined using high-speed camera images. It was determined that the ignition delay times and fuel time-histories were able to be accurately predicted by mechanisms in the literature for pressures up to 30 atm but the literature mechanisms were unable to predict the carbon monoxide time-histories beyond qualitative trends for the various fuels. It was also determined that the carbon monoxide had a string effect on the fluid dynamics of the experiments resulting in a significantly smaller chemical reaction zone. Experiments were also performed to examine the effects of water as a diluent with a ratio up to 66% of the total diluent on the ignition delay times. Using the experimental data, a global kinetic mechanism was created for methane and syngas to predict the ignition delay times and the carbon monoxide time-histories for pressures up to 300 atm.

Experimental and Modelling Studies of Coal/biomass Oxy-fuel Combustion in a Pilot-scale PF Combustor

Experimental and Modelling Studies of Coal/biomass Oxy-fuel Combustion in a Pilot-scale PF Combustor
A Book

by Nelia Jurado Pontes

  • Publisher : Unknown Publisher
  • Release : 2014
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Formation and Removal of SOx and NOx in Pressurized Oxy-fuel Coal Combustion

Formation and Removal of SOx and NOx in Pressurized Oxy-fuel Coal Combustion
A Book

by Muhammad Jahangir Malik

  • Publisher : Unknown Publisher
  • Release : 2019
  • Pages : 136
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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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.

Assess of Biomass Co-firing Under Oxy-fuel Conditions on Hg Speciation and Ash Deposit Formation

Assess of Biomass Co-firing Under Oxy-fuel Conditions on Hg Speciation and Ash Deposit Formation
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2018
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Highlights: In coal case, oxy-firing enhances Hg capture on the finest particles. Main affection of oxy-conditions on Hg fate is observed for cofiring processes. Oxy-cofiring increases Hg oxidation in the flue gas phase. At low temperatures, HCl(g) fraction is decreased in oxy-cofiring vs air. Oxy-fuel combustion reduces chloride deposition versus sulphates formation. Abstract: In the last years oxy-fuel combustion has been seen as an attractive method for oxygenated fuels, such as biomass, for controlling simultaneously the excess of heat arising from coal combustion and flue gas emissions (CO2, NOx, SO2 ...). However there is a lack of information with respect to the fate of other toxic pollutants found in trace concentrations, such as mercury, in oxy-fuel processes operating with biomass fuels. In addition, the modified conditions and flue gas composition leads to more corrosive environments which needs of previous evaluation to minimize possibly damaging processes in the boilers, furthermore in case of employing biomass of high alkaline compounds contents. The present work evaluates the effect of oxy-combustion processes of sub-bituminous coal and coal/ biomass (thistle) blends on mercury partitioning and speciation, under both air and different oxy-fuel combustion atmospheres, by means of a bubbling fluidized bed combustor at laboratory scale. HSC Chemistry 6.1 was supplemented for the interpretation of the experimental results and for the analysis of ash deposits formation. Hg speciation was seen to be more affected by oxy-fuel combustion during the co-firing tests than in coal combustion, with an increment in Hg oxidation at low temperatures (T

Oxyfuel Combustion for Clean Energy Applications

Oxyfuel Combustion for Clean Energy Applications
A Book

by Medhat A. Nemitallah,Mohamed A. Habib,Hassan M. Badr

  • Publisher : Springer
  • Release : 2019-02-11
  • Pages : 368
  • ISBN : 3030105881
  • Language : En, Es, Fr & De
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This book aims to be the reference book in the area of oxyfuel combustion, covering the fundamentals, design considerations and current challenges in the field. Its first part provides an overview of the greenhouse gas emission problem and the current carbon capture and sequestration technologies. The second part introduces oxy-fuel combustion technologies with emphasis on system efficiency, combustion and emission characteristics, applications and related challenges. The third part focuses on the recent developments in ion transport membranes and their performance in both oxygen separation units and oxygen transport reactors (OTRs). The fourth part presents novel approaches for clean combustion in gas turbines and boilers. Computational modelling and optimization of combustion in gas turbine combustors and boiler furnaces are presented in the fifth part with some numerical results and detailed analyses.

Contribution to CFD Modeling of Lignite Oxy-fuel Combustion with Special Focus on Radiation Properties

Contribution to CFD Modeling of Lignite Oxy-fuel Combustion with Special Focus on Radiation Properties
A Book

by Tanin Kangwanpongpan

  • Publisher : Unknown Publisher
  • Release : 2013
  • Pages : 281
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Atomistic Simulation of Coal Char Isothermal Oxy-fuel Combustion: Char Reactivity and Behavior

Atomistic Simulation of Coal Char Isothermal Oxy-fuel Combustion: Char Reactivity and Behavior
A Book

by Anonim

  • Publisher : Unknown Publisher
  • Release : 2016
  • Pages : 329
  • ISBN : 9876543210XXX
  • Language : En, Es, Fr & De
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Graphical abstract: Highlights: Atomistic combustion simulation (simplistic) using large-scale coal char models. Increased pore volume (micro- and mesoporosity) increased burn-off rate. Char transitions and burning modes were evaluated. Abstract: Here a new automated and inexpensive atomic simulation approach including sequential oxygen diffusion and simplified reaction was created to explore the char reactivity and combustion behavior during oxy-fuel combustion. Two large-scale (>40, 000 carbon atoms) coal chars (higher- and lower-porosity chars) that differ primarily in pore volume and pore size distribution were evaluated against graphite with similar number of carbon atoms. The structural transformations, total atoms, reactive atoms, their location, conversion, rate (number of atoms reacting), size of the char, and apparent density were captured. Post analysis evaluated the total porosity, micro/mesoporosity volume, and atomic surface area. The higher porosity char burn-off was ∼38% more rapid than the graphite (number of steps), similar to the lower porosity char (∼33% faster). The peak reactivity followed the maximum atomic surface area (with a delay of 5–10% conversion) than decreased—as there were fewer reactive carbons. Porosity volume increases with conversion until 50–70% where the porosity declines. For both chars the microporosity contribution increased until 30–35% conversion then the pores either grow or coalesce into the mesoporous classification. The chars burning modes are initially changing density (pore growth accompany mass loss) until ∼50% conversion when the mode became a combination of changing density and shrinking core. Graphite was less reactive and followed a shrinking core consistent with the simulation restrictions. This approach is likely to aid in the exploration of the influence of char structure and conversion conditions upon reactivity and char behavior in combustion and gasification.