Download or read book Computational Modeling and Experimental Studies on NO subscript X Reduction Under Pulverized Coal Combustion Conditions Technical Progress Report Sixth Quarter April 1 June 30 1996 written by and published by . This book was released on 1996 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter, the experiments for nitric oxide reburning with a combination of methane and acetylene were conducted successfully. With the failure of ozonator lamp in the NOx analyzer shortly thereafter, the experimental study of nitric oxide reburning with a combination of methane and ammonia could not be completed. In the meantime, a coal feeder was designed and a purchase order was sent out for the building of the coal feeder. Presented herein are the experimental results of NO reburning with methane/acetylene. The results are consistent with model predictions.
Download or read book Summary of Meetings 14 October 1998 written by and published by . This book was released on 1998 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Modeling and Experimental Studies on NO subscript X Reduction Under Pulverized Coal Combustion Conditions Technical Progress Report Second Quarter April 1 1995 June 30 1995 written by and published by . This book was released on 1995 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented in this second quarterly report are the computational results of NO reburning with (a) a combination of methane and acetylene (i) with the reaction mechanism listed in the first quarterly report and (ii) with the updated reaction mechanism (Table 1 of this report); and (b) a combination of methane and ammonia. The impact of the updated reaction scheme was not significant on the results of NO reburning with methane/acetylene; however, the reaction scheme needed changes to improve the accuracy of some reactions of crucial intermediates in methane/ammonia reburning. An extensive literature survey was made in order to update the mechanism.
Download or read book Computational Modeling and Experimental Studies on NOsub X Reduction Under Pulverized Coal Combustion Conditions Third Quarterly Technical Progress Report written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Modeling and Experimental Studies on NOsub X Reduction Under Pulverized Coal Combustion Conditions Technical Progress Report Second Quarter April 1 1995 June 30 1995 written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Modeling and Experimental Studies on NO x Reduction Under Pulveerized Coal Combustion Conditions Quarterly Technical Progress Report July 1 September 30 1997 written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several experiments were conducted during this quarter to study the NO(subscript x) reduction effectiveness of lignite coal, activated carbon and catalytic sites such as calcium sulfide and calcium carbide. While some of the coals/chemicals could be fed easily, some needed the mixing with silica gel to result in a uniform flow through the feeder. Several trial runs were performed to ensure proper feeding of the material before conducting the actual experiment to record NO(subscript x) reduction. The experimental approach has been the same as presented in the past two quarterly reports with the coal reburning experiments. Partial reduction is achieved through methane addition for SR2=0.95 conditions and then coal or the catalyst is introduced to see if there is further reduction. Presented below are the results of the experiments conducted during this quarter.
Download or read book Computational Modeling and Experimental Studies on NO x Reduction Under Pulverized Coal Combustion Conditions written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter efforts were made to conduct reburning experiments with coal. Our efforts met with partial success but there arose persistent problems with the operation of the coal feeder. This entire quarter has been the most challenging time for the research team in terms of solving the problems and carrying out the intended experiments. Discussed below are some of the results as well as challenges. We hope to overcome the problems in due time. At the writing of this report, some parts of the coal feeder are being rebuilt by MK Fabrication.
Download or read book Computational Modeling and Experimental Studies on NO sub X Reduction Under Pulverized Coal Combustion Conditions Progress Report February 1 1995 March 31 1995 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first quarterly report of this three-year program which began on February 1, 1995. This program involves computer simulation studies to aid in planning and conducting a series of experiments that will extend our knowledge of reburning process. The objective of this work is to find nitric oxide reduction effectiveness for various reburning fuels and identify both homogeneous and heterogeneous reaction mechanisms characterizing NO reduction. To begin with, computer simulation studies have been undertaken. The updated version of CHEMKIN II (1994) package has been acquired from Sandia National Laboratories and put to use for the preliminary runs involving reburning of nitric oxide with methane. This report presents results from these computations.
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 Computational Modeling and Experimental Studies on NOsub X Reduction Under Pulverized Coal Combustion Conditions Progress Report Fevruary 1 1995 March 31 1995 written by and published by . This book was released on 1995 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 Technical Progress Report Fifth Quarter 1 January 1996 31 March 1996 written by and published by . This book was released on 1996 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter, the focus was on getting the experimental facility ready for operation. Upon receiving all the pieces of equipment, the research team first spent a great deal of time in calibration of various instruments and then began assembling the pieces for the experimental work. The use of Swage-lock fittings helped in arresting the gas leaks fairly easily. The entire assembly consisted of teflon tube connections (a) from gas cylinders to the flow meters, manifold and buffer vessel, (b) from buffer vessel to the inlet of the reactor enclosed in the middle, by a furnace, (c) from the exhaust end of the reactor to the NOx analyzer via gas dryer and (d) from the analyzer to the vent. Details of the experimental setup are given in the subsequent section. Once the setup was checked for leaks and the leaks were arrested, the facility was operational. Several experiments on NO reburning with methane were undertaken. The flow rates for various gases were calculated for five reburning stoichiometric ratios and the experiments were conducted for three different reaction temperatures. The results are presented later on in this report. These results indicate favorable reduction of NO by reburning with methane, consistent with their computer projections, and hence, present a good base for investigating further on nitric oxide reburning with other fuels as well. Experiments on nitric oxide reburning with (1) a combination of methane and acetylene, and (2) a combination of methane and ammonia, will be considered in the next quarter. The computer simulation results submitted in the Second Quarterly Report indicate further reduction of NO with the addition of acetylene/ammonia to methane as reburn fuel. These results will be verified experimentally in the ensuing quarter.
Download or read book Computational Modeling and Experimental Studies on NO3 Reduction Under Pulverized Coal Combustion Conditions Progress Report February 1 1995 March 31 1995 written by and published by . This book was released on 1995 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first quarterly report of this three-year program which began on February 1, 1995. This program involves computer simulation studies to aid in planning and conducting a series of experiments that will extend our knowledge of reburning process. The objective of this work is to find nitric oxide reduction effectiveness for various reburning fuels and identify both homogeneous and heterogeneous reaction mechanisms characterizing NO reduction. To begin with, computer simulation studies have been undertaken. The updated version of CHEMKIN II (1994) package has been acquired from Sandia National Laboratories and put to use for the preliminary runs involving reburning of nitric oxide with methane. This report presents results from these computations.
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 Kinetics and Mechanisms of NO subscript X written by and published by . This book was released on 1995 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project is concerned with the mechanism of reduction of both NO and N2O by carbons. It was recognized some years ago that NO formed during fluidized bed coal combustion can be heterogeneously reduced in-situ by the carbonaceous solid intermediates of combustion. This has been recently supplemented by the knowledge that heterogeneous reaction with carbon can also play an important role in reducing emissions of N2, but that the NO-carbon reactions might also contribute to formation of N2. The precise role of carbon in N2 reduction and formation has yet to be established. Interest in the N2 and N2O-char reactions has been significant in connection with both combustor modeling, as well as in design of post-combustion NO(subscript x) control strategies. In our studies, a DuPont thermogravimetric analyzer (TGA) is used for the char reactivity studies. The temperature and mass are recorded as function of time, using a Macintosh computer and software for simultaneous apparatus control and data acquisition. Specific surface areas of char samples were determined by the N2 BET method at 77 K.A standard flow-type adsorption device (Quantasorb) was used for the measurements. Prior to surface area analysis, all samples were outgassed in a flow of nitrogen at 573 K for 3 hours. The carbonaceous solids used were resin char, graphite, coconut char and a Wyodak coal char. As was noted in the last report, carbons derived from different original materials show quite similar behaviors, in terms of the trends, but there are significant differences in actual reaction rates. It was shown that the spread of the reaction rate data from different studies, when expressed on a mass of carbon reactant- or surface area-basis, was almost the same.
Download or read book DEVELOPMENT OF A VALIDATED MODEL FOR USE IN MINIMIZING NOx EMISSIONS AND MAXIMIZING CARBON UTILIZATION WHEN CO FIRING BIOMASS WITH COAL written by and published by . This book was released on 2002 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the sixth Quarterly Technical Report for DOE Cooperative Agreement No. DE-FC26-00NT40895. A statement of the project objectives is included in the Introduction of this report. Two additional biomass co-firing test burns were conducted during this quarter. In the first test (Test 10), up to 20% by weight dry hardwood sawdust and switchgrass was compiled with Galatia coal and injected through the dual-register burner. Galatia coal is a medium-sulfur Illinois Basin coal ((almost equal to)1.0% S). The dual-register burner is a generic low-NO(subscript x) burner that incorporates two independent wind boxes. In the second test (Test 11), regular ((almost equal to)70% passing 200 mesh) and finely ground ((almost equal to)90% passing 200 mesh) Pratt Seam coal was injected through the single-register burner to determine if coal grind affects NO(subscript x) and unburned carbon emissions. The results of these tests are presented in this quarterly report. Significant progress has been made in implementing a modeling approach to combine reaction times and temperature distributions from computational fluid dynamic models of the pilot-scale combustion furnace with char burnout and chemical reaction kinetics to predict NO(subscript x) emissions and unburned carbon levels in the furnace exhaust. No additional results of CFD modeling have been received as delivery of the Configurable Fireside Simulator is expected during the next quarter. Preparations are under way for continued pilot-scale combustion experiments with the single-register burner and a low-volatility bituminous coal. Some delays have been experienced in the acquisition and processing of biomass. Finally, a project review was held at the offices of Southern Research in Birmingham, on February 27, 2002.
Download or read book Formation and Destruction of Nitrogen Oxides in Coal Combustion Second Quarterly Report April 1 1988 June 30 1988 written by and published by . This book was released on 1988 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of stoichiometric constraints under equilibrium conditions provides us with the following information related to reburning as a NO reduction technology: (1) The stoichiometry of air to fuel is the most important stoichiometry of air to fuel is the most important stoichiometric variable for reburning; (2) based on equivalent energy production, the comparative reduction efficiencies of the reburning fuels follow the trend: methane> ethane, ammonia> butane> aromatics, coal> CO; (3) the nitrogen in burning coals causes increases in equilibrium NO; (4) equilibrium TFN is not very sensitive in inlet NO concentration; (5) the heat carried by the flue gas in reburning could push the NO reduction toward equilibrium. If so, reburning has a strong correlation with air staging with air preheat. Further experimental verification is required.
Download or read book Investigation of Mineral Transformations and Ash Deposition During Staged Combustion Quarterly Technical Progress Report April 1 1995 June 30 1995 written by and published by . This book was released on 1995 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress during the seventh quarter of a three-year study was made in four task areas: (1) analysis of coals, (2) improvements to the reactor system, (3) parametric testing of the target coals, and (4) analysis of samples from the combustion tests. A problem with our analysis system was discovered and corrected. Recent analyses of the Pittsburgh {number_sign}8 coal (after repulverizing) were redone and results are reported. A new design of the deposit probe and an air preheater were added this quarter. Parametric testing of the Pittsburgh {number_sign}8 coal continued this quarter. Analytical results from these tests show sulfur release and iron transformations as a function of test conditions and sampling location. Deposit samples were also collected from the Pittsburgh coal at three different stoichiometric ratios. Operating conditions appeared to have a significant effect on deposit formation. Finally, specific tasks for the next quarter have been identified and reported.
