Combustion Improvement System in Boilers and Incinerators

2003 ◽  
Author(s):  
Wlodzimierz Blasiak ◽  
Weihong Yang
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Combustion Chamber ◽  
Flue Gas ◽  
Operating Conditions ◽  
Waste Incinerator ◽  
The Novel ◽  
Biomass Waste ◽  
Injection Angle ◽  
Waste Incinerators

This work presents the main features, advantages and evaluation of applications of the novel “Ecotube” combustion improvement and emission reduction system by Ecomb AB of Sweden and Synterprise, LLC of Chattanooga, Tennessee. In the Ecotube system, the nozzles used for mixing are put on the suitable position inside the combustion chamber to control uniformity of temperature, mixing and reactants distribution in boilers and incinerators since the formation and reduction of pollutants (NO, CO and VOC) and in-furnace reduction processes (Air/Fuel staging, SNCR, flue gas recirculation and SOx reduction by dry sorbent injection) are related directly to mixing in a combustion chamber. The novel Ecotube combustion improvement system allows better control of mixing of the gases for example from a primary combustion zone with secondary combustion air or a recirculated flue gas. By means of the novel system it is possible to better control the residence time and to some degree gas phase temperature distribution as well as the heat release distribution in the furnace of the waste incinerators or boilers. This new combustion improvement system can be applied to supply different gas or liquid media — for example air, fuel, urea or even solid powder. Using the system a more efficient and environmentally clean combustion or incineration process can be performed. The Ecotube System may be used to meet increasingly stringent environmental emissions regulations, such as NOx SIP Call, while it delivers added benefits of reduced and stabilized CO and reduced fly ash and improved boiler efficiency. The study tool used in this work to present influence of the Ecotube system design on temperature as well as uniformity of reactants and flow field is numerical modeling. Using this tool, the influence of the position of the Ecotube system and the injection angle of the nozzles are studied. The studied boilers included the biomass waste incinerator, municipal solid waste incinerator and coal fired boiler. The concept of the Heat Release Distribution Ratio is proposed to classify the heat release inside the upper furnace of the boilers or incinerators. The results show that Ecotube spreads reaction zone over a larger furnace volume. The furnace flame occupation coefficient can be as high as 45% with the Ecotube system and it is around 40% higher comparing with the conventional multinozzle mixing system. Ecotube system allows keeping far more uniform heat release distribution, more uniform temperature distribution, and thus longer life of the heat transfer surfaces inside the furnace. Position of the Ecotube system and the injection angle of the nozzles are of primary importance and can be used as a technical parameter to control the boiler operation at different loads and varying operating conditions.

Change of Operation Parameters of Waste Incinerator by Formation of Deposits

2016 ◽  
Vol 832 ◽  
pp. 207-212
Author(s):  
Jiří Moskalík
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
Large Scale ◽  
Negative Impact ◽  
Municipal Waste ◽  
Working Fluid ◽  
Operating Parameters ◽  
Waste Incinerator ◽  
Gas Channel ◽  
Waste Incinerators

This article is focused on formation of unwanted deposits in the municipal waste incinerator and their influence on incinerator operation. The solid deposits build up on heat transfer surfaces in flue gas channel of waste incinerator. The power stations fired solid fuels sometimes can have problems with growing of deposits. On this point of view, the municipal waste incinerators are a special category, because the municipal waste contains a lot of different types of compounds. Formation of deposits on heat transfer surfaces has in generally bad influence on operating parameters of waste incinerator. Deposits decrease the heat transfer from the flue gas into the working fluid and thereby it reduces the efficiency of incineration facility. The effect of decreasing of heat transfer ability was investigated on large-scale waste incinerator in Brno, where were monitored changes of operating parameters before and after the planned shutdown of the device. Deposits can too affect the shape of flue gas channel and thereby reduce his size. It can have more negative impact on waste incinerator operation.

Numerical Analysis of the Acoustic Transfer Behaviour of Pressure Ducts Utilised for Microphone Measurements in Combustion Chambers

2010 ◽  
Author(s):  
Jean-Michel Lourier ◽  
Axel Widenhorn ◽  
Berthold Noll ◽  
Michael Sto¨hr ◽  
Manfred Aigner
Keyword(s):  
Temperature Distribution ◽  
Transfer Function ◽  
Combustion Chamber ◽  
Acoustic Signal ◽  
Acoustic Waves ◽  
Atmospheric Temperature ◽  
Operating Conditions ◽  
Thermal Loads ◽  
Combustion Chambers ◽  
Acoustic Transfer Function

Acoustic measurements within combustion chambers are expensive due to high thermal loads applied on the measurement devices at operating conditions. As a more feasible substitute, pressure ducts can be used to lead acoustic waves from combustion chambers to externally mounted microphones. Since these pressure ducts are purged by nitrogen at atmospheric temperature, high thermal loads are avoided. However, the acoustic signal measured within the pressure ducts is altered compared to the signal within the combustion chamber. This change in the acoustic signal can be characterised by means of the acoustic transfer function of the pressure duct, which mainly depends on the pressure ducts geometry and the combustion chambers temperature distribution. The main subject of the present paper is to analyse the influence of the combustion chambers temperature distribution on the acoustic transfer function of pressure ducts. For this scope, experiments at standard conditions and transient CFD simulations for different temperature distributions have been carried out. The acoustic signal measured in the pressure duct is found to be amplified with increasing temperatures within the combustion chamber. Moreover this amplification grows with increasing frequency of the acoustic signals.

Heat Release Analysis of Oxygen-Enriched Diesel Combustion

1993 ◽  
Vol 115 (4) ◽  
pp. 761-768 ◽  
Author(s):  
D. Assanis ◽  
E. Karvounis ◽  
R. Sekar ◽  
W. Marr
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Oxygen Enrichment ◽  
Operating Conditions ◽  
Diesel Combustion ◽  
The Novel ◽  
Pressure Data ◽  
Engine Operation ◽  
Combustion Simulation ◽  
Release Analysis

A heat release correlation for oxygen-enriched diesel combustion is being developed through heat release analysis of cylinder pressure data from a single-cylinder diesel engine operating under various levels of oxygen enrichment. Results show that standard combustion correlations available in the literature do not accurately describe oxygen-enriched diesel combustion. A novel functional form is therefore proposed, which is shown to reproduce measured heat release profiles closely, under different operating conditions and levels of oxygen enrichment. The mathematical complexity of the associated curve-fitting problem is maintained at the same level of difficulty as for standard correlations. When the novel correlation is incorporated into a computer simulation of diesel engine operation with oxygen enrichment, the latter predicts pressure traces in excellent agreement with measured pressure data. This demonstrates the potential of the proposed combustion simulation to guide the application of oxygen-enriched technology successfully to a variety of multicylinder diesel systems.

Influence of Flame and Burner Transfer Matrix on Thermoacoustic Combustion Instability Modes and Frequencies

2010 ◽  
Author(s):  
Giovanni Campa ◽  
Sergio Mario Camporeale
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Transfer Matrix ◽  
Acoustic Waves ◽  
Gas Turbines ◽  
Combustion Instability ◽  
Experimental Tests ◽  
Full Scale ◽  
Operating Conditions ◽  
Actual Geometry

The main origin of combustion instability in modern gas turbines is considered to be related to the interaction between acoustic waves and flame perturbations. An important role is played by the characteristics of combustion chamber and burners, because they influence the operating conditions at which the instability may occur. Experimental tests carried out on single burner arrangements fail to give adequate indications for the design of a full scale combustion chamber, due to the interaction of the local flame fluctuations with the propagation of the pressure waves, that have a wavelength of the same order of magnitude of the main dimensions of the chamber. Therefore there is a large interest on developing techniques able to make use of the data gathered from tests carried out on a single burner for predicting the thermoacoustic behavior of the combustion chamber at full scale with its actual geometry. A three dimensional finite element code has been developed for predicting acoustically driven combustion instabilities in combustion systems with complex geometries. The code allows one to identify the frequencies at which thermoacoustic instabilities are expected and the growth rate of the pressure oscillations, at the onset of instability, under the hypothesis of linear behaviour of the acoustic waves. The code permits to represent heat release fluctuations through an n–τ Flame Transfer Function (FTF) model and to adopt the transfer matrix method for modelling the burners. The FTF and the burner transfer matrix (BTM), as well as the temperature field and the flame location, needed for the simulation, can be obtained from experimental tests. Moreover, the code is able to make use of the local distribution of n and τ that can be evaluated from computational fluid dynamic studies on the single burner. The paper shows the importance of the flame characteristics, such as dimensions and shape of the heat release zone and its location within the combustor, underlying their influence on the instability of the modes and so the potential of the proposed method as a design tool for defining the burner characteristics and the acoustic impedance at the boundaries of the combustion chamber.

Could biomass-fueled boilers be operated at higher steam temperatures? Part 3: Initial analysis of costs and benefits

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 65-78 ◽  
Author(s):  
W.B.A. (SANDY) SHARP ◽  
W.J. JIM FREDERICK ◽  
JAMES R. KEISER ◽  
DOUGLAS L. SINGBEIL
Keyword(s):  
Flue Gas ◽  
Power Plants ◽  
Superheated Steam ◽  
Black Liquor ◽  
Simulation Software ◽  
Operating Conditions ◽  
Costs And Benefits ◽  
Steam Generation ◽  
Fireside Corrosion ◽  
Corrosion Resistant

The efficiencies of biomass-fueled power plants are much lower than those of coal-fueled plants because they restrict their exit steam temperatures to inhibit fireside corrosion of superheater tubes. However, restricting the temperature of a given mass of steam produced by a biomass boiler decreases the amount of power that can be generated from this steam in the turbine generator. This paper examines the relationship between the temperature of superheated steam produced by a boiler and the quantity of power that it can generate. The thermodynamic basis for this relationship is presented, and the value of the additional power that could be generated by operating with higher superheated steam temperatures is estimated. Calculations are presented for five plants that produce both steam and power. Two are powered by black liquor recovery boilers and three by wood-fired boilers. Steam generation parameters for these plants were supplied by industrial partners. Calculations using thermodynamics-based plant simulation software show that the value of the increased power that could be generated in these units by increasing superheated steam temperatures 100°C above current operating conditions ranges between US$2,410,000 and US$11,180,000 per year. The costs and benefits of achieving higher superheated steam conditions in an individual boiler depend on local plant conditions and the price of power. However, the magnitude of the increased power that can be generated by increasing superheated steam temperatures is so great that it appears to justify the cost of corrosion-mitigation methods such as installing corrosion-resistant materials costing far more than current superheater alloys; redesigning biomassfueled boilers to remove the superheater from the flue gas path; or adding chemicals to remove corrosive constituents from the flue gas. The most economic pathways to higher steam temperatures will very likely involve combinations of these methods. Particularly attractive approaches include installing more corrosion-resistant alloys in the hottest superheater locations, and relocating the superheater from the flue gas path to an externally-fired location or to the loop seal of a circulating fluidized bed boiler.

scholarly journals Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2729
Author(s):  
Ireneusz Pielecha ◽  
Sławomir Wierzbicki ◽  
Maciej Sidorowicz ◽  
Dariusz Pietras
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Rapid Compression Machine ◽  
Process Indicators ◽  
Rapid Compression

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

Finite element method estimation of temperature distribution of automotive tire using one-way-coupled method

2021 ◽  
pp. 095440702110087
Author(s):  
Zumrat Usmanova ◽  
Emin Sunbuloglu
Keyword(s):  
Thermal Analysis ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Complex Geometry ◽  
Rolling Resistance ◽  
Operating Conditions ◽  
Deformation Analysis ◽  
Coupled Method ◽  
Experimental Values ◽  
Hysteretic Loss

Numerical simulation of automotive tires is still a challenging problem due to their complex geometry and structures, as well as the non-uniform loading and operating conditions. Hysteretic loss and rolling resistance are the most crucial features of tire design for engineers. A decoupled numerical model was proposed to predict hysteretic loss and temperature distribution in a tire, however temperature dependent material properties being utilized only during the heat generation analysis stage. Cyclic change of strain energy values was extracted from 3-D deformation analysis, which was further used in a thermal analysis as input to predict temperature distribution and thermal heat generation due to hysteretic loss. This method was compared with the decoupled model where temperature dependence was ignored in both deformation and thermal analysis stages. Deformation analysis results were compared with experimental data available. The proposed method of numerical modeling was quite accurate and results were found to be close to the actual tire behavior. It was shown that one-way-coupled method provides rolling resistance and peak temperature values that are in agreement with experimental values as well.

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

2021 ◽  
pp. 146808742110050
Author(s):  
Stefania Esposito ◽  
Lutz Diekhoff ◽  
Stefan Pischinger
Keyword(s):  
Gas Exchange ◽  
Combustion Chamber ◽  
Direct Injection ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Operating Parameters ◽  
Gaseous Pollutant ◽  
Fuel Ratio ◽  
No Emissions

With the further tightening of emission regulations and the introduction of real driving emission tests (RDE), the simulative prediction of emissions is becoming increasingly important for the development of future low-emission internal combustion engines. In this context, gas-exchange simulation can be used as a powerful tool for the evaluation of new design concepts. However, the simplified description of the combustion chamber can make the prediction of complex in-cylinder phenomena like emission formation quite challenging. The present work focuses on the prediction of gaseous pollutants from a spark-ignition (SI) direct injection (DI) engine with 1D–0D gas-exchange simulations. The accuracy of the simulative prediction regarding gaseous pollutant emissions is assessed based on the comparison with measurement data obtained with a research single cylinder engine (SCE). Multiple variations of engine operating parameters – for example, load, speed, air-to-fuel ratio, valve timing – are taken into account to verify the predictivity of the simulation toward changing engine operating conditions. Regarding the unburned hydrocarbon (HC) emissions, phenomenological models are used to estimate the contribution of the piston top-land crevice as well as flame wall-quenching and oil-film fuel adsorption-desorption mechanisms. Regarding CO and NO emissions, multiple approaches to describe the burned zone kinetics in combination with a two-zone 0D combustion chamber model are evaluated. In particular, calculations with reduced reaction kinetics are compared with simplified kinetic descriptions. At engine warm operation, the HC models show an accuracy mainly within 20%. The predictions for the NO emissions follow the trend of the measurements with changing engine operating parameters and all modeled results are mainly within ±20%. Regarding CO emissions, the simplified kinetic models are not capable to predict CO at stoichiometric conditions with errors below 30%. With the usage of a reduced kinetic mechanism, a better prediction capability of CO at stoichiometric air-to-fuel ratio could be achieved.

Electromagnetic performance and thermal analysis of a novel permanent magnet fluxed-switching coupler

2021 ◽  
pp. 1-18
Author(s):  
Lezhi Ye ◽  
Yulong Zhang ◽  
Mingguang Cao
Keyword(s):  
Temperature Distribution ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Three Dimensional ◽  
Load Condition ◽  
Maximum Load ◽  
Maximum Temperature ◽  
The Novel ◽  
Transient Field ◽  
Three Dimensional Finite Element

To solve the problem of complex operating device and permanent magnets (PMs) demagnetization at high temperature, a new type of permanent magnet fluxed-switching coupler (PMC) with synchronous rotating adjuster is proposed. Its torque can be adjusted by rotating a switched flux angle between the adjuster and PMs along the circumferential direction. The structural feature and working principle of the PMC are introduced. The analytical model of the novel PMC was established. The torque curves are calculated in transient field by using the three-dimensional finite element method (3-D FEM). The temperature distribution of the novel PMC under rated condition is calculated by 3-D FEM, and the temperature distribution of the PM is compared with that of the conventional PMC. The simulation and test results show that the maximum temperature of copper disc and PM of the novel PMC are 100 °C and 48 °C respectively. The novel PMC can work stably for a long time under the maximum load condition.

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