Download or read book NOx formation and reduction by a coal a lignite an anthracite and a petroleum coke in conditions of cement plant calciner written by Julien Cances and published by . This book was released on 2006 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'industrie cimentière est extrêmement consommatrice d'énergie. Cette énergie est principalement fournie par la combustion de solides carbonés pulvérisés. Jusqu'à 60 % de cet apport en combustible peut être injecté dans le précalcinateur. La combustion de solides carbonés produit des polluants, au premier rang desquels on trouve les NOx. Plusieurs techniques de réduction de NOx existent à l'heure actuelle. L'une des plus prometteuses en terme d'efficacité, conjuguée à son coˆut, est le “reburning” qui consiste en une injection secondaire de combustible, créant ainsi une zone riche et favorable à la réduction des NOx. L'injection de combustibles solides dans les précalcinateurs de cimenteries s'apparente à cette technique. Ces solides interagissent avec les NOx par différents mécanismes : par l'intermédiaire de réactions dans la phase gaz avec les matières volatiles dégagées lors de la pyrolyse ; par l'intermédiaire de réactions hétérogènes entre le résidu solide et son environnement gazeux : l'oxydation du char qui produit des espèces azotées et la réduction du NO sur le char. Une démarche couplée d'expérimentations et de modélisation a été développée pour déterminer l'influence relative de ces différents phénomènes. Les combustibles utilisés sont de quatre types distincts et sont communément utilisés dans les cimenteries : lignite, charbon, anthracite et petcoke. Ainsi, les réactions hétérogènes élémentaires – dévolatilisation, oxydation du char et réduction du NO sur le char – ont-elles été caractérisées individuellement par des expériences et des modélisations spécifiques. On observe une forte disparité entre les quatre combustibles, autant sur les paramètres cinétiques des réactions hétérogènes que sur la quantités de matières volatiles dégagées. Enfin, les expériences et modélisations représentatives de l'ensemble des réactions qui se déroulent simultanément lors du reburning dans les conditions précalcinateur de cimenteries ont été conduites. Il apparaît que l'effet de la réduction du NO dans la phase gaz est du même ordre de grandeur que l'effet de la réduction sur le char après un temps de séjour des particules de 2 s. La réduction du NO sur le char croît continuellement avec la température alors que la réduction dans la phase gaz présente des singularités en fonction de la température pour les combustibles : la réduction du NO est plus faible à 900C dans le cas du lignite et du charbon qu'à 800 et 1000C. L'étude détaillée de ces singularités a été menée et a permis de déterminer les chemins réactionnels intervenant dans la formation et réduction de NOx dans la phase gazeuse
Download or read book Formation of NOx and Other Products from Chemically Bound Nitrogen in Coal Combustion written by David W. Blair and published by . This book was released on 1981 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Carbonisation of Coal written by Vivian Byam Lewes and published by . This book was released on 1912 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Changes During Calcination of Coke and Anthracite written by Svein Richard Brandtzæg and published by . This book was released on 1985 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book How Coal Properties Influence Emissions written by Robert M. Davidson and published by . This book was released on 2000 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aspects of NOx Formation and Reduction in Coal Fired Combustion Systems written by R. Payne and published by . This book was released on 1981 with total page 42 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 The Use of Petroleum Coke in Coal fired Plants written by Rohan Fernando and published by . This book was released on 2001 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Combustion Conditions on the Formation of NOx in Brown Coal Flames written by G. J. Byrne and published by . This book was released on 1983 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coal and Coke written by Frederick Henry Wagner and published by . This book was released on 1916 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cement Production Technology written by Anjan Kumar Chatterjee and published by CRC Press. This book was released on 2018-04-27 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is an outcome of the author’s active professional involvement in research, manufacture and consultancy in the field of cement chemistry and process engineering. This multidisciplinary title on cement production technology covers the entire process spectrum of cement production, starting from extraction and winning of natural raw materials to the finished products including the environmental impacts and research trends. The book has an overtone of practice supported by the back-up principles.
Download or read book NOx Formation in Coal Utilisation written by British Coal and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nox Formation in Coal Utilisation written by British Coal Corporation Staff and published by . This book was released on 1994-12-01 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The reduction of NOx emissions by staged combustion for a range of diverse coal fired under boiler simulated conditions written by W. Phelan and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Feasibility and NOx Reduction Potential of Flameless Oxidation in Pulverised Coal Combustion written by Dragisa Ristic and published by Cuvillier Verlag. This book was released on 2012-10-30 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the 1990, the flameless oxidation technology has been successfully proven as low-NOx combustion technology for gaseous hydrocarbon fuels, and the recent application of this technology to solid fuels such as pulverised coal has also become an area of interest. The objective of this thesis is to evaluate the feasibility and the potential of the flameless oxidation technology in the pulverised coal combustion. Firstly, the experimental studies on pulverised coal flameless oxidation process are conducted at a bench-scale test facility (5 to 10 kWth). In the next step, a suitable burner design in a pilot scale of approximately 300 kWth is developed, built up and experimentally studied. Detailed exhaust gas and inflame measurements of the temperature and, main species are carried out in order to address the specific aspects of pulverised coal flameless oxidation. Furthermore, to indicate the relevant NOx reduction mechanisms in the pulverised coal flameless oxidation process. In contrast to the conventional pulverised coal combustion, which has luminous and aerodynamically stabilised flames, the flameless oxidation combustion process has been achieved without a clearly visible flame. In the pulverised coal flameless oxidation mode, intensive internal recirculation is enhanced by a high injection velocity of the combustion air, and thus dilutes the combustion zone and heats up the coal particles in the primary pyrolysis zone. Once the coal particles are rapidly heated up, the processes of pyrolysis and volatile matter release are facilitated. Consequently, local reducing zone is formed, devolatilisation is enhanced, ignition delay is suppressed, combustion stability is improved and NOx emissions are reduced remarkably. A high internal recirculation of the oxygen-lean hot combustion products into the primary pyrolysis zone promotes an early devolatilisation and a decrease in ignition delay, which are two important factors for NOx reduction processes. Hence, a valuable potential of pulverised coal flameless oxidation is in the improved homogeneous gas phase kinetics and an enhanced homogeneous NO reburning mechanism. Besides NO reduction in the homogeneous gas phase, it is indicated that the NO reduction on the char surface in the heterogeneous and homogeneous gas phases is important as well, i.e. char NO reduction reaction and catalytic reduction of NO by CO on the char surface, in the pulverised coal flameless oxidation. As an overall conclusion, the PC FLOXTM (Pulverised Coal Flameless Oxidation) burner technology generally is evaluated as a perspective technology to provide low cost low NOx burners for utility boilers. Moreover, the PC FLOXTM burner technology offers the possibility of a lower cost alternative to the current approach of utilising SCR to enable power plants to meet current and future specific requirements on NOx emissions. However, despite all the advantages of this technology, it has been recognised that there are considerable technical challenges to the implementation of PC FLOXTM burners in utility boilers. High pressure loss in the main combustion air supply, boiler and burner design, arrangement of burners, start-up and shutdown procedures, etc. all require significant further work in order to bring the PC FLOXTM burner technology closer to the utility scale boilers.
Download or read book NOx reduction in coal combustion written by G. J. Hesselman and published by . This book was released on 1992 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NOx formation from Different Coal Types in a Bench Scale Reactor Under Excess Air and Staged Combustion Conditions written by S. L. Chen and published by . This book was released on 1982 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:
