Modelling and Optimization of the NO Formation in an Industrial Glass Furnace

1992 ◽  
Vol 114 (4) ◽  
pp. 514-523 ◽  
Author(s):  
M. G. Carvalho ◽  
V. S. Semia˜o ◽  
P. J. Coelho
Keyword(s):  
Nitric Oxide ◽  
Mathematical Model ◽  
Glass Furnace ◽  
Dominant Role ◽  
Formation Rate ◽  
Heat Transfer Process ◽  
Operating Conditions ◽  
Industrial Glass ◽  
Nitric Oxide Emissions ◽  
Glass Furnaces

The effects of combustion excess-air level, air preheating, and fuel composition on the nitric oxide emissions from an industrial glass furnace are studied through the use of a mathematical model. The mathematical model is based on the solution of the time-averaged form of the governing conservation equations for mass, momentum, energy, and chemical species. The k-ε turbulence model is employed for modelling the turbulence fluxes. The flame is modelled as a turbulent diffusion one and the chemical reactions associated with the heat release are assumed to be fast. The fluctuations of scalar properties are accounted for by use of a clipped-Gaussian probability density function. The thermal radiation, playing the dominant role in the heat-transfer process, is modelled using the discrete transfer method. Because of the high temperatures at which industrial glass furnaces operate a considerable amount of thermal NO is formed. The present work presents a model, based on a chemical kinetic approach, to predict the nitric oxide emissions from industrial glass furnaces. The Zeldovich mechanism, retaining the reverse reactions, is incorporated in the model in order to predict the instantaneous NO net formation rate from atmospheric nitrogen. The whole procedure is applied to a cross-fired regenerative furnace. A set of parametric studies is carried out, demonstrating the ability of the model to evaluate the influence of changes in operating conditions on the NO emissions.

scholarly journals Influence of Fuel Composition and Spray Characteristics on Nitric Oxide Formation

1989 ◽  
Author(s):  
K. K. Rink ◽  
A. H. Lefebvre
Keyword(s):  
Nitric Oxide ◽  
Drop Size ◽  
Perforated Plate ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Fuel Composition ◽  
Circular Array ◽  
Nitric Oxide Formation ◽  
Nitric Oxide Emissions ◽  
Standard Instrumentation

Measurements of nitric oxide emissions are carried out on a continuous flow combustor when operating over wide ranges of fuel/air ratio at pressures up to 1.52 MPa (15 atmos). Fuel is supplied to the flame zone from a circular array of 30 equispaced miniature airblast atomizers which is incorporated into a perforated-plate flameholder. Standard instrumentation and sampling techniques are used to measure pollutant emissions over wide ranges of mean fuel drop size. The results obtained with several selected fuels demonstrate the effects of variations in fuel composition, fuel drop size, and combustor operating conditions on nitric oxide emissions.

INFLUENCE OF VAPOR AND CRYSTAL FORMATION PROCESSES ON HEAT EXCHANGE IN FILM VAPORATORS

2021 ◽  
pp. 32-40
Author(s):  
O. Koshelnik ◽  
V. Pavlova ◽  
T. Pugacheva ◽  
O. Kruglyakova ◽  
O. Dolobovska
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Energy Consumption ◽  
Heat Exchange ◽  
Solid Phase ◽  
Heat Transfer Process ◽  
Operating Conditions ◽  
Crystal Formation ◽  
Phase Content ◽  
Three Phase

Evaporators for changing the concentration of solutions have a different design, depending on the type of processed substance. Significant energy consumption in such equipment is associated with the need for removing large quantity of liquid phase. Multiple-effect evaporators are used to reduce the energy consumption of the evaporation process, but such equipment is quite expensive. Evaporators with secondary vapor heat reusing that operate in film mode can be an alternative to multi-effect evaporators. This equipment can operate efficiently across minimal temperature differences due to secondary vapor compressors. The disadvantage of this device is strict requirements for impurities in solutions. Impurities create deposits (incrustations) of various substances on the heat transfer surfaces, which worsens the operating conditions. If crystallizing solutions are used in evaporators with reusing of secondary vapor heat, then one of the ways to reduce the rate of heating surfaces incrustation is to add a solid phase to the initial solution. A mathematical model is proposed to describe the processes of heat and mass transfer during the film flow of crystallizing solutions, which are accompanied by a change in the physical characteristics of the solution and the formation of deposits. The model considers a three-phase liquid suspension with a varying phase content. Two stages of vaporization including vaporization on the surface of the liquid and on the surface of heat exchange are presented. The mathematical model involves the equations of continuity, energy and heat transfer, as well as the equations of motion of a three-phase flow with a changing phase content for both stages of vaporization, taking into account that solid phase turbulizes the flow and intensifies the heat transfer process. This mathematical model makes it possible to study the effect of the solid phase on heat transfer processes and the rate of incrustation in evaporators with reuse of secondary vapor heat.

The Use of a Three-Zone Combustion Model to Determine Nitric Oxide Emissions From a Homogeneous-Charge, Spark-Ignited Engine

2003 ◽  
Author(s):  
Jerald A. Caton
Keyword(s):  
Nitric Oxide ◽  
Engine Speed ◽  
Combustion Process ◽  
Core Region ◽  
Operating Conditions ◽  
Combustion Model ◽  
Nitric Oxides ◽  
Cycle Simulation ◽  
Nitric Oxide Emissions ◽  
Homogeneous Charge

Nitric oxide emissions were estimated for a homogeneous-charge, spark-ignited automotive engine using a cycle simulation which employed three zones for the combustion process: (1) unburned gas, (2) adiabatic core region, and (3) boundary-layer gas. The use of the adiabatic core region has been shown to be especially necessary to capture the production of nitric oxides which are highly temperature dependent. The effects of major engine parameters such as equivalence ratio, spark timing, inlet manifold pressure, and engine speed on nitric oxide emissions are examined. In particular, the detail reasons for the effects of these engine parameters on the nitric oxide emissions are presented. Comparisons are completed between the computed values and a set of published measurements for the nitric oxide concentrations. Although not all engine parameters were known, reasonable agreement is demonstrated for most cases. In particular, the variations of nitric oxide concentrations as engine speed increased were duplicated. As an example, four operating conditions are examined in detail to help explain the measured results. Nitric oxide emissions are shown to be mainly the net result of gas temperatures, oxygen concentrations, and residence times.

Design of the Blast Furnace Wall Structure Made of Efficient Materials. Part 4. Calculation Examples

2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Boundary Value Problems ◽  
Transfer Process ◽  
Rational Design ◽  
Boundary Value ◽  
Heat Transfer Process ◽  
Furnace Wall ◽  
Time Interval

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

Greater nitrous and nitric oxide emissions from the soil between rows than under the canopy in subtropical tea plantations

Geoderma ◽  
2021 ◽  
Vol 398 ◽  
pp. 115105
Author(s):  
Zhaoqiang Han ◽  
Jinyang Wang ◽  
Pinshang Xu ◽  
Zhirong Sun ◽  
Cheng Ji ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Tea Plantations ◽  
Nitric Oxide Emissions

scholarly journals Process Engineering of the Acetone-Ethanol-Butanol (ABE) Fermentation in a Linear and Feedback Loop Cascade of Continuous Stirred Tank Reactors: Experiments, Modeling and Optimization

Fuels ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 108-129
Author(s):  
Katja Karstens ◽  
Sergej Trippel ◽  
Peter Götz
Keyword(s):  
Feedback Loop ◽  
Early Stage ◽  
Formation Rate ◽  
Abe Fermentation ◽  
Operating Conditions ◽  
Stirred Tank ◽  
Second Phase ◽  
Stirred Tank Reactors ◽  
Continuous Stirred Tank ◽  
Continuous Stirred Tank Reactors

The production of butanol, acetone and ethanol by Clostridium acetobutylicum is a biphasic fermentation process. In the first phase the carbohydrate substrate is metabolized to acetic and butyric acid, in the following second phase the product spectrum is shifted towards the economically interesting solvents. Here we present a cascade of six continuous stirred tank reactors (CCSTR), which allows performing the time dependent metabolic phases of an acetone-butanol-ethanol (ABE) batch fermentation in a spatial domain. Experimental data of steady states under four operating conditions—with variations of the pH in the first bioreactor between 4.3 and 5.6 as well as the total dilution rate between 0.042 h−1 and 0.092 h−1—were used to optimize and validate a corresponding mathematical model. Beyond a residence time distribution representation and substrate, biomass and product kinetics this model also includes the differentiation of cells between the metabolic states. Model simulations predict a final product concentration of 8.2 g butanol L−1 and a productivity of 0.75 g butanol L−1 h−1 in the CCSTR operated at pHbr1 of 4.3 and D = 0.092 h−1, while 31% of the cells are differentiated to the solventogenic state. Aiming at an enrichment of solvent-producing cells, a feedback loop was introduced into the cascade, sending cells from a later state of the process (bioreactor 4) back to an early stage of the process (bioreactor 2). In agreement with the experimental observations, the model accurately predicted an increase in butanol formation rate in bioreactor stages 2 and 3, resulting in an overall butanol productivity of 0.76 g L−1 h−1 for the feedback loop cascade. The here presented CCSTR and the validated model will serve to investigate further ABE fermentation strategies for a controlled metabolic switch.

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