Analysis of Chemical-looping Combustion Systems for Power Generation PDF Download

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Publisher:
ISBN:
Category :
Languages : en
Pages : 53

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Author: Samuel C. Bayham
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The significant increase in the average global temperature has been determined to be the result of anthropogenic release of greenhouse gases, such as carbon dioxide, into the atmosphere. With this in mind, nations have considered a carbon tax for emission of carbon dioxide into the atmosphere from point sources, such as power plants. However, carbon capture from power plants has proven to be expensive both economically and in terms of energy penalty due to endergonic nature of molecular separation. A number of technologies have been developed, such as oxycombustion, and gasification combined cycle that are able to capture carbon. However, these technologies require a means of providing either providing pure oxygen to oxidize the fuel or a molecular means to separate the carbon dioxide from nitrogen, both of which have the potential to be prohibitively expensive, in terms of capital expense and parasitic load. Chemical looping combustion has been considered a transformational technology for simultaneous carbon capture and electricity generation. The technology consists of providing oxygen to the fuel using a metal oxide in one reactor, producing pure carbon dioxde as the product, and combusting the metal oxide in a separate reactor to produce heat for steam and electricity generation. This configuration has been extensively studied by researchers around the world in small-scale pilot units. Furthermore, the iron-based CDCL technology has been demonstrated at Ohio State in a 25-kWth subpilot unit with reasonable success, with high conversions of solid fuels such as sub-bituminous coal and waste products such as metallurgical coke fines. Furthermore, the carbon dioxide purity in the flue gas is around 99%, with low values of carbon monoxide, methane, and hydrogen impurities. As of this writing, over 680 hours of operation have been performed in this unit, with a successful 200 hour continuous campaign. Furthermore, extensive laboratory bench unit studies have been performed that were used to verify the carbon char and volatile kinetics. This work attempts to review state-of-the-art chemical looping combustion systems for power generation. Designs and experimental results from pilot-scale chemical looping combustion demonstration units are discussed in relation to parameters relevant for a practical commercial unit. Furthermore, the work also reviews the design and experimental results from the Coal Direct Chemical Looping Unit developed at Ohio State. An extensive mass and energy balance has been performed to determine the system efficiency. Finally, further analysis shows the effects of sulfur, nitrogen and alkali materials on the oxygen carrier.

Author: Ronald W. Breault
Publisher: John Wiley & Sons
ISBN: 3527342028
Category : Business & Economics
Languages : en
Pages : 488

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This comprehensive and up-to-date handbook on this highly topical field, covering everything from new process concepts to commercial applications. Describing novel developments as well as established methods, the authors start with the evaluation of different oxygen carriers and subsequently illuminate various technological concepts for the energy conversion process. They then go on to discuss the potential for commercial applications in gaseous, coal, and fuel combustion processes in industry. The result is an invaluable source for every scientist in the field, from inorganic chemists in academia to chemical engineers in industry.

Author: Liang-Shih Fan
Publisher: John Wiley & Sons
ISBN: 1118063139
Category : Technology & Engineering
Languages : en
Pages : 353

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This book presents the current carbonaceous fuel conversion technologies based on chemical looping concepts in the context of traditional or conventional technologies. The key features of the chemical looping processes, their ability to generate a sequestration-ready CO2 stream, are thoroughly discussed. Chapter 2 is devoted entirely to the performance of particles in chemical looping technology and covers the subjects of solid particle design, synthesis, properties, and reactive characteristics. The looping processes can be applied for combustion and/or gasification of carbon-based material such as coal, natural gas, petroleum coke, and biomass directly or indirectly for steam, syngas, hydrogen, chemicals, electricity, and liquid fuels production. Details of the energy conversion efficiency and the economics of these looping processes for combustion and gasification applications in contrast to those of the conventional processes are given in Chapters 3, 4, and 5.Finally, Chapter 6 presents additional chemical looping applications that are potentially beneficial, including those for H2 storage and onboard H2 production, CO2 capture in combustion flue gas, power generation using fuel cell, steam-methane reforming, tar sand digestion, and chemicals and liquid fuel production. A CD is appended to this book that contains the chemical looping simulation files and the simulation results based on the ASPEN Plus software for such reactors as gasifier, reducer, oxidizer and combustor, and for such processes as conventional gasification processes, Syngas Chemical Looping Process, Calcium Looping Process, and Carbonation-Calcination Reaction (CCR) Process. Note: CD-ROM/DVD and other supplementary materials are not included as part of eBook file.

Author: Edward Frederic Obert
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Paul Fennell
Publisher: Elsevier
ISBN: 0857097601
Category : Technology & Engineering
Languages : en
Pages : 467

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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

Author: Tianjiao Chen (S.M.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 117

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Chemical looping combustion (CLC) is one of the most promising technologies to achieve carbon capture in fossil fuel power generation plants. A novel rotary-bed reactor concept was proposed by Zhao et. al. [1] in 2013. It is a compact gas fueled CLC reactor that could achieve high fuel conversion and carbon separation efficiencies. It is different from the widely applied and tested fluidized-bed reactor that employs metal oxides coated on particle shaped support materials as the reaction median. In the new reactor, the active metal oxidizes are coated on the surfaces of channel shaped structural material in the new reactor. Due to the different reaction mechanism, an alternative experimental platform with the capability of performing reaction kinetic analysis for disk or channel shaped samples was required needed. The sample selection, characterization and preparation methods are discussed, followed by the introduction of the experimental system design and initial calibration and tuning results. Preliminary oxidation kinetic studies are carried out using the real-time gas analysis system to obtain the concentration contours of the effluent gas species. Commercial 13 wt% copper(II) oxide particles prepared through impregnation method are used as the reaction median. The reactant gas used in the oxidation cycles is 8%, 13% and 21% oxygen in argon, operated at 700 - 800 *C; and 10% hydrogen in argon is used for the reducing cycles.

Author: Calin-Cristian Cormos
Publisher: Elsevier Inc. Chapters
ISBN: 0128085320
Category : Science
Languages : en
Pages : 18

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Reducing greenhouse gas emissions generated from energy sector in the following years is a compulsory step to the transition to low carbon resource efficient economy. Among various methods to reduce CO2 emissions, Carbon Capture and Storage (CCS) technologies have a special importance. A promising carbon capture method to be applied in energy conversion processes for reducing the energy penalty associated with carbon capture is based on chemical looping systems. This paper investigates CO2 capture based on chemical looping systems suitable to be applied in an IGCC plant for energy vectors poly-generation with emphasis on hydrogen and power co-generation case. The coal-based IGCC cases produce about 400 – 600 MW net electricity and a flexible hydrogen output from zero up to 150 MW hydrogen (based on hydrogen lower heating value) with almost total carbon capture rate of the used fossil fuel. A particular accent is put in the paper on the assessment of process integration issues of gasifier island and syngas conditioning line with the chemical looping unit, mathematical modeling and simulation of whole plant, thermal and power integration of chemical looping unit in the whole IGCC plant (using pinch analysis) and discussing quality specifications for captured CO2 stream considering storage in geological formations or using for EOR.

Author: Yitao Zhang
Publisher:
ISBN:
Category : Chemical engineering
Languages : en
Pages :

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With the rising concern of climate change, extensive research has been conducted in recent years on the mitigation of global warming. Greenhouse gas emissions are considered as the key driver of global warming. Among the various greenhouse gases, CO2 is the major contributor to the greenhouse effect. Therefore, mitigation of CO2 emission is the key to address global warming. Chemical looping is an energy conversion technology that can directly produce a concentrated CO2 stream, ready for sequestration and utilization, without the need for an individual CO2 separation step, and thus, has the potential to drastically reduce the energy consumption and cost associated with CO2 capture in carbonaceous fuel energy conversion systems. In this dissertation, process modeling and analysis are conducted on solid fuel power production processes to quantify the energy penalty and exergy losses associated with CO2 capture technologies, including state-of-the-art solvent-based CO2 absorption, oxy-combustion using high purity oxygen, and chemical looping combustion technology. Following the comparison of various power production processes using solid fuel with and without CO2 capture, a comprehensive analysis is performed to investigate the effect of varying operation conditions on the performance of chemical looping combustion reactor system. The coal-direct chemical looping process is a chemical looping combustion technology using moving bed reducer configuration that can directly use coal as the feedstock without requiring upstream gasification steps. An integrated 250 kWth coal-direct chemical looping pilot unit using iron-based oxygen carriers has been constructed and demonstrated for long-term continuous operations. The principles for the design and operation of the primary reactor system are discussed in this dissertation. The results of a successful 288-hour continuous demonstration with pulverized bituminous coal are reported. The results from the pilot unit highlight the concept of the chemical looping combustion process as a promising solid fuel combustion technology with CO2 capture. To investigate chemical looping technology for hydrogen production, process simulation and analysis is performed on two distinct configurations for chemical looping H2 generation process. The simulation results of two chemical looping H2 generation configurations are compared with the conventional steam-methane reforming system to underscore the attractiveness of the chemical looping configurations.

Author: Chen Chen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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To address the issues caused by CO2 emissions from the fossil-fueled combustion process by the power generation system, the comprehensive analysis of large-scale dynamic power plant systems with varying power load and supervisory control architecture that include carbon footprint constraints is presented. Model-based, system-scale dynamic simulation and optimization are useful tools for assessment and prediction of plant performance, decisions on the design configuration, and the tuning of operating procedures and control strategies. Efficiency estimates are provided for all the scenarios studied, and these estimates are optimal in terms of design configuration, control architecture and process sequencing. Moreover, the need to mitigate CO2 emissions leads power plant operators to explore advanced options for efficiency optimization and integration of power plants with carbon capture and storage (CCS) technologies. Process intensification options are explored for near-carbon-neutral, natural-gas-fueled combined cycle power plants, wherein the conventional combustor is replaced by a series of chemical-looping combustion reactors. Integrated power plant models are presented in this work, such as models of steam thermal power plants and combined cycle power plants. This work shows a complete workflow of data collection, model development, validation, control tuning, dynamic optimization formulation and solution, and supervisory control architectures for power generation systems. With the consideration of further reducing CO2 emissions, dynamic modeling and optimization are deployed to design chemical-looping combustion integrated with combined cycle power plants with optimal configuration and performance. The overall plant efficiency is improved by optimizing the chemical-looping reactor design and operation, and modifying the combined plant configuration and design. Moreover, process intensification for chemical-looping combustion reactors was explored in the form of reactor modularization. Specifically, fixed bed reactors were explored that are split into small reactor modules emulating the performance of a simulated moving bed reactor. The scheduling of the reactor modules was solved as a dynamic optimization problem that decides process variables and time intervals for the operation of each module at different chemical looping stages. The optimal scheduling of semi-batch reactors in cyclic arrangement revealed more complex patterns of gas switching that improve the thermodynamic efficiency of the process.