Download or read book Modeling and Simulation of SOx and NOx Reduction Processes in Pulverized Coal Furnaces written by and published by Cuvillier Verlag. This book was released on 2003-12-18 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT The current work briefly reviews the formation mechanisms and reduction approaches of the pollutants SOx and NOx in coal combustion and focuses on the simulation of the lower-cost in-furnace measures ƒ{ the dry additive process (DAP) for SOx reduction and the reburning as well as the advanced reburning (hybrid reburning/SNCR) techniques for NOx reduction. In addition, the influence of sulfur compounds on NOx formation is investigated. The major workings include: Simulation of the dry additive desulfurization process (DAP): Different models ƒ{ shrinking core model (SCM), pore model (PM) and grain model (GM) ƒ{ are implemented to describe the gas-particle reaction. Relevant processes such as the sintering of the additive, the self-retention by coal ash, the thermal equilibrium of the sulfation reaction are accounted for and modeled. A comprehensive model for the DAP with calcium based additives is subsequently established and integrated into a combustion CFD (computational fluid dynamics) code AIOLOS, in both Eulerian and Lagrangian schemes. The model is verified with experiments on a test reactor. Mechanism reduction and simulation of reburning/SNCR Processes: A method for reduction of kinetic mechanisms is introduced. A program tool is developed for automatic reduction of detailed reaction mechanisms. Reduced mechanisms for reburning and hybrid reburning/SNCR processes are developed and implemented into the CFD code. CFD-calculations with the reduced mechanisms are performed and compared with experimental measurements to comprehensively evaluate the simulation approach. It is shown that the detailed simulation is capable of modeling the complex reburning and SNCR processes with acceptable computing time and achieves reasonable results in wide parameter ranges. Study of the influence of sulfur compounds on NOx formation: The effect of SO2 on NOx formation is experimentally investigated and analysed with kinetic mechanisms. It is indicated that the presence of SO2 inhabits the NOx formation and reduce the NOx emissions in normal air-rich combustion. Under air-staging conditions, SO2 addition has no obvious influence on the final NOx emissions.
Download or read book Emissions Reduction written by A. Tomita and published by Elsevier. This book was released on 2001-12-18 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade the topic of emissions reduction and control has remained an important area of research due to the enforcement of various Government policies in an attempt to minimize the impact on the environment. One area in which a great deal of research has been conducted to address this policy is NOx/SOx suppression. However, despite the progress that has been made over this time period, further research into the most effective method of reducing NOx/SOx emissions is still urgently required. In developed countries, a more stringent requirement in the level of emissions (such as is NOx/SOx component of less than 10ppm) will be enforced in the near future. Developing countries will also need a new technology that is effective and that is suited to each countries needs. Additional research and development efforts are thus necessary to meet such requirements. This compendium contains a collection of key papers themed around NOx/SOx emissions from combustion of hydrocarbon resources and the attempts to secure an efficient and effective method for reducing these emissions. These key papers are taken from the journals Fuel, Fuel Processing Technology and Progress in Energy and Combustion Science.
Download or read book Reduction of NOx Emissions from Pulverized Coal Furnaces written by Kenneth Leroy Nielsen and published by . This book was released on 1973 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling and Simulation of SOx and NOx Formation Under Oxy Coal Combustion Conditions written by Michael Müller and published by . This book was released on 2015 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predictions of NOx Emissions in Pulverized Coal Combustion written by Niko Hachenberg and published by . This book was released on 2014 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this research work was to develop a transferable mathematically simple model which gives the possibility to make fast and easy predictions regarding the NOx emission behavior of a broad-spectrum of coals within a certain combustion environment. In this context, this thesis is a further step of a common ongoing investigation focused on predicting NOx emissions from self-sustaining, pulverized coal combustion in dry bottom firing systems. A comprehensive literature research focused on already published NOx prediction approaches from scientific publications based on fundamental quantitative relationships or empirical algorithms and statistical relationships was also carried out in this context. This research concentrated on three specific areas which were found to constitute a major gap in the knowledge of NOx formation in industrial full-scale applications: the fuel properties; the dependence of furnace geometry factors; and the specific operating conditions. The developed model shows a strong statistical significance with a coefficient of determination of 0.9876 and a standard error of 28 mg / m3 STPdry at 6 % O2 based on 142 observations coming from 28 utility boilers. Direct comparisons between model history and observations reported by other researchers have also shown very good conformities. For that background, this thesis form a good basis for identifying individual factors which contributes to system related NOx emissions in order to investigate how variations in the process parameters affect the emission level. Perhaps, as contribution to the understanding of NOx formation during coal combustion what is still an imperfectly understood phenomenon, or as basis for possible process optimization which might find application on pulverized coal-fired boilers to make the world a little bit more green.
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 Modelling and Prediction written by Ruksana Moreea-Taha and published by . This book was released on 2000 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kitten Tales written by and published by . This book was released on 1961 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book COMPUTATIONAL MODELING AND EXPERIMENTAL STUDIES ON NOx REDUCTION UNDER PULVERIZED COAL COMBUSTION CONDITIONS written by and published by . This book was released on 1998 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, both computer simulation and experimental studies were conducted to investigate several strategies for NO(subscript x) reduction under pulverized coal combustion conditions with an aim to meet the stringent environmental standards for NO(subscript x) control. Both computer predictions and reburning experiments yielded favorable results in terms of NO(subscript x) control by reburning with a combination of methane and acetylene as well as non-selective catalytic reduction of NO(subscript x) with ammonia following reburning with methane. The greatest reduction was achieved at the reburning stoichiometric ratio of 0.9; the reduction was very significant, as clearly shown in Chapters III and V. Both the experimental and computational results favored mixing gases: methane and acetylene (90% and 10% respectively) and methane and ammonia (98% and 2%) in order to get optimum reduction levels which can not be achieved by individual gases at any amounts. Also, the above gaseous compositions as reburning fuels seemed to have a larger window of stoichiometric ratio (SR2 0.9) as opposed to just methane (SR2=0.9) so as to reduce and keep NO(subscript x) at low ppm levels. From the various computational runs, it has been observed that although there are several pathways that contribute to NO(subscript x) reduction, the key pathway is NO -- HCN --> NH3 --> N2 + H2. With the trends established in this work, it is possible to scale the experimental results to real time industrial applications using computational calculations.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book REDUCTION OF NOx EMISSION FROM COAL COMBUSTION THROUGH OXYGEN ENRICHMENT written by University of Wyoming Research Corporation. Western Research Institute and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: BOC Process Gas Solutions and Western Research Institute (WRI) conducted a pilot-scale test program to evaluate the impact of oxygen enrichment on the emissions characteristics of pulverized coal. The combustion test facility (CTF) at WRI was used to assess the viability of the technique and determine the quantities of oxygen required for NOx reduction from coal fired boiler. In addition to the experimental work, a series of Computational Fluid Dynamics (CFD) simulations were made of the CTF under comparable conditions. A series of oxygen enrichment test was performed using the CTF. In these tests, oxygen was injected into one of the following streams: (1) the primary air (PA), (2) the secondary air (SA), and (3) the combined primary and secondary air. Emission data were collected from all tests, and compared with the corresponding data from the baseline cases. A key test parameter was the burner stoichiometry ratio. A series of CFD simulation models were devised to mimic the initial experiments in which secondary air was enriched with oxygen. The results from these models were compared against the experimental data. Experimental evidence indicated that oxygen enrichment does appear to be able to reduce NOx levels from coal combustion, especially when operated at low over fire air (OFA) levels. The reductions observed however are significantly smaller than that reported by others (7-8% vs. 25-50%), questioning the economic viability of the technique. This technique may find favor with fuels that are difficult to burn or stabilize at high OFA and produce excessive LOI. While CFD simulation appears to predict NO amounts in the correct order of magnitude and the correct trend with staging, it is sensitive to thermal conditions and an accurate thermal prediction is essential. Furthermore, without development, Fluent's fuel-NO model cannot account for a solution sensitive fuel-N distribution between volatiles and char and thus cannot predict the trends seen in the experiment.
Download or read book ORD Publications Announcement written by Center for Environmental Research Information (U.S.) and published by . This book was released on 1982 with total page 774 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamental Study of NOx Reduction Processes During Staged Combustion of Pulverized Coal written by R. J. Yang 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 Energy Research Abstracts written by and published by . This book was released on 1994 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1989 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advancements in Low NOx Tangential Firing Systems written by and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most cost effective method of reducing nitrogen oxide emissions when burning fossil fuels, such as coal, is through in-furnace NOx reduction processes. ABB Combustion Engineering, Inc. (ABB CE), through its ABB Power Plant Laboratories has been involved in the development of such low NOx pulverized coal firing systems for many years. This development effort is most recently demonstrated through ABB CE's involvement with the U.S. Department of Energy's (DOE) {open_quotes}Engineering Development of Advanced Coal Fired Low-Emission Boiler Systems{close_quotes} (LEBS) project. The goal of the DOE LEBS project is to use {open_quotes}near term{close_quotes} technologies to produce a commercially viable, low emissions boiler. This paper addresses one of the key technologies within this project, the NOx control subsystem. The foundation for the work undertaken at ABB CE is the TFS 2000{trademark} firing system, which is currently offered on a commercial basis. This system encompasses sub-stoichiometric combustion in the main firing zone for reduced NOx formation. Potential enhancements to this firing system focus on optimizing the introduction of the air and fuel within the primary windbox to provide additional horizontal and vertical staging. As is the case with all in-furnace NOx control processes, it is necessary to operate the system in a manner which does not decrease NOx at the expense of reduced combustion efficiency.
Download or read book Technical and Economic Evaluation of NOx Control for Coal fired Cyclone Furnaces written by Kenneth E. Noll and published by . This book was released on 1976 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
