1,720,973 research outputs found
Developments of a modeling tool for problem solving in industrial boilers: Application of Reactor Network Analysis for the evaluation of fireside corrosion of heat exchangers by H2S
No full textAn algorithm for extracting chemical reactor network models from CFD simulation of industrial combustion systems
No full textChemical engineering models significantly reduce the amount of computational time for detailed chemical kinetics with respect to the direct implementation of a three-dimensional CFD code, but to be of real aid in dealing with industrial problems, they should be generated from CFD outputs in an automatic and objective way that does not depend on the specific case to be modeled. In the present study, the features of an algorithm developed and encoded for this purpose are shown: The criteria and logical steps adopted in generating chemical reactor networks (CRNs) from CFD simulation of industrial combustion devices are presented, and a method for evaluating the accuracy of the simplification is discussed. The assessment of the algorithm focuses on its performance in yielding CRNs capable of reproducing the concentration of main species calculated by CFD. This is a necessary condition for the subsequent use of comprehensive and detailed reaction schemes for the prediction of pollutant and harmful species involved in combustion
Modelling practical combustion systems and predicting NOx emissions with an integrated CFD based approach
No full textAn integrated methodology for the simulation of practical combustion systems and NOx prediction is presented. It is based on 3D CFD simulation coupled to a postprocessor which yields reactor networks, extracted from 3D fields, as 'equivalent' simplified flow models for which it is possible to use a detailed reaction kinetics. The study of two glass melting furnaces is presented to illustrate the methodology. The furnaces were experimentally characterised, then CFD simulations were performed, setting the suitable boundary conditions for the radiative heat exchange and the sub-model for the chemistry. From each CFD simulation, a chemical reactor network was extracted to perform the computation of the secondary product combustion species by means of a complex kinetics mechanism. An evaluation of the models was given comparing the measurements with the temperature of the CFD field and the NOx prediction. Finally, an estimate of the effect of some NOx reducing techniques was given. (C) 2002 Elsevier Science Ltd. All rights reserved
Reactor network analysis: An integrated methodology for the modeling of combustion chemistry in industrial systems
No full textPrediction Of Rapid Biomass Devolatilization Yields With An Upgraded Version Of The Bio-CPD Model
Full text linkAnalysis of syngas reburn technology for industrial boilers with advanced chemical engineering models
No full textThe outcome of an integrated methodology for analysis of combustion processes applied to technical feasibility of controlling NOx emissions and unburned carbon in ash from industrial scale plants was presented. The modeling methodology was based on an integrated use of furnace probing measurements coupled with different simulation tools: CFD code (IPSE) for 3D simulation of combustion chambers, PROATES for the convection pass, and Chemical Engineering Models (RNA) for pollutant emissions and burnout predictions. The solid phase included heterogeneous NO reduction by char and heterogeneous char oxidation with a detailed population balance (800 size burnout classes) keeping track of size, density change and burnout. As working case, to better explain the potentiality offered by this analytical approach, a study addressed to evaluate the best firing configuration for a tangentially-fired utility boiler supplied with pulverized coal by employing synthesis gas (syngas) as secondary fuel is presented. The case studied was chosen as increasing attention to the use of renewable and sustainable energy resources has led to consider, as near term option, the possibility of co-firing syngas (i.e. synthetic gas produced by gasification of biomass or waste) with coal in the existing large-scale pulverized coal power plants. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004)
CFD plus reactor network analysis: an integrated methodology for the modeling and optimisation of industrial systems for energy saving and pollution reduction
No full textAn integrated methodology for the simulation of practical combustion systems and NO, prediction was developed. It is based on 3D CFD simulation coupled to a postprocessor which yields reactor networks, extracted from 3D fields, as 'equivalent' simplified flow models for which it is possible to use a detailed reaction kinetics. A review of some relevant application is presented to illustrate how this methodology can help in design and optimisation of industrial combustion systems towards a comprehensive improvement of the environmental performances. (C) 2002 Elsevier Science Ltd. All rights reserved
Conformal Vector Fields and Conformal Ricci Solitons on -Kenmotsu Manifolds
No full textThe object of the present paper is to give some properties of alpha-Kenmotsu manifolds admitting holomorphically planar conformal vector fields. The nature of conformal Ricci solitons is also analyzed on such manifolds
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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