Wyniki wyszukiwania - BazTech

1

Chemical and thermal methods for removing ammonia from fly ashes

Mazur M., Janda T., Żukowski W.

Technical Transactions

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2017

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Vol. 6(114)

31--50

EN

The presence of ammonia in ashes (i.e. ammonia slip) is a direct consequence of the methods used for denitrification – selective catalytic and non-catalytic reduction (SCR, SNCR). The excess unreacted ammonia used in both of these methods passes as a constituent to ash, impairing its properties, and thus affects the quality of the commercial product. The summary of the available methods for removing NH3 from fly ashes is presented. Both chemical and thermal methods of removing NH3 are described. The results of the chemical methods depend on the kind of additional reagents used and composition of fly ashes. Thermal methods seem to be simpler and easier to use, but they are used mainly on the smaller scale.

PL

Obecność amoniaku w popiele (tzw. poślizg amoniaku) jest bezpośrednią konsekwencją stosowanych metod odazotowania spalin – katalitycznej i niekatalitycznej selektywnej redukcji (SCR, SNCR). Stosowany w obu tych metodach nadmiar amoniaku przechodzi w formie nieprzereagowanej do popiołu, pogarszając jego właściwości użytkowe i tym samym wpływając na jego jakość jako produktu komercyjnego. Prezentujemy przegląd dostępnych metod usuwania NH3 z popiołu, chemicznych a także termicznych. Efektywność metod chemicznych zależy od rodzaju zastosowanego substratu i składu popiołu lotnego. Metody termiczne wydają się prostsze i łatwiejsze w zastosowaniu, ale są używane głównie w instalacjach o mniejszej skali.

2

A tool for on-line control of high-temperature corrosion hazard in steam boilers

Hardy T., Kakietek S., Janda T.

Archivum Combustionis

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2017

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Vol. 37 nr 2

107--118

EN

High temperature (low oxygen) corrosion processes in coal-fired boilers are intensified primarily by the use of low-emission (NOx) combustion techniques, that are associated with production of a reducing gas atmosphere near evaporator walls. For over 10 years a diagnostic system for corrosion risks determination was developed, based on continuous measurement of the composition of the flue gas in the boundary layer and artificial intelligence techniques. This paper presents the experience with the implementation of such a diagnostic system on the OP-230 hard coal fired boiler to identify the corrosion hazard of one of the evaporator walls. The obtained results indicate that it is possible to significantly simplify the measuring system by reducing the number of measurement points on the boiler wall which reduces costs of installation and exploitation. This is possible through the use of neural networks to visualize the measurement results. Comparisons of the O2 and CO concentration maps in the boundary layer obtained from measurements at 26 measurement points and results from the Rachel software based on neural network performance and 5-point measurement showed a high compatibility of obtained results. At present, on-line electrical resistance corrosion probes are included in the monitoring system to allow an assessment of the actual corrosion rate of entire evaporator tubes.

3

Online monitoring system of air distribution in pulverized coal-fired boiler based on numerical modeling

Żymełka P., Nabagło D., Janda T., Madejski P.

Archives of Thermodynamics

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2017

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Vol. 38, no. 4

109–-125

EN

Balanced distribution of air in coal-fired boiler is one of the most important factors in the combustion process and is strongly connected to the overall system efficiency. Reliable and continuous information about combustion airﬂow and fuel rate is essential for achieving optimal stoichiometric ratio as well as efficient and safe operation of a boiler. Imbalances in air distribution result in reduced boiler efficiency, increased gas pollutant emission and operating problems, such as corrosion, slagging or fouling. Monitoring of air ﬂow trends in boiler is an effective method for further analysis and can help to appoint important dependences and start optimization actions. Accurate real-time monitoring of the air distribution in boiler can bring economical, environmental and operational benefits. The paper presents a novel concept for online monitoring system of air distribution in coal-ﬁred boiler based on real-time numerical calculations. The proposed mathematical model allows for identification of mass ﬂow rates of secondary air to individual burners and to overﬁre air (OFA) nozzles. Numerical models of air and flue gas system were developed using software for power plant simulation. The correctness of the developed model was verified and validated with the reference measurement values. The presented numerical model for real-time monitoring of air distribution is capable of giving continuous determination of the complete air flows based on available digital communication system (DCS) data.

4

The use of optical flame scanners for combustion process analysis in OP-650 power boiler

Nabagło D., Podgórski P., Janda T., Sokołowski P.

Archivum Combustionis

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2015

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Vol. 35 nr 2

99--116

EN

Optical flame scanners are commonly used in flame supervision systems (FSS) for the purpose of protection against of flame loss inside the combustion chamber. The presence or absence of flame is indicated by the scanner according to analysis of electromagnetic radiation changes in the wavelength range 700÷1700 nm emitted by supervised flame. The use of digital signal processing technology in IR spectrum allows to recognize the supervised flame with very high ability and allows to use the signals for combustion process analysis. Electromagnetic field disturbances in the infrared due to changes in the flame, are determined by the combustion process properties in burner zone i.e. the burner heat load, excess air ratio, temperature of PF mixture, the amount and swirl of primary and secondary air. The ability of use the information provided by the scanners - in this unique parameters supervised flame i.e. flame temperature, power spectral density and the radiation amplitude changes - became the basis for the initiation of studies regarding the optical flame scanners use for combustion process analysis. The paper presents the first results of work on the use of optical flame scanners in the analysis of combustion process in 650 t/h live steam power boiler in EDF Power Plant in Rybnik. The boiler is supplied by 5 coal mill units, each of coal mills supplies 4 pulverized coal burners (PF burners). The boiler has a start-up installation consisting of 12 heavy oil burners placed in PF burners and individually controlled by 12 flame scanners. Based on the analysis of the measuring data obtained from scanners an assessment of the quality of the combustion process for 2 coal mill units (8 PF burners) have been done.

5

Combustion process optimization by using immune optimizer in power boiler

Śladewski Ł., Nabagło D., Janda T., Chachuła J.

Archivum Combustionis

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2015

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Vol. 35 nr 1

51--63

EN

Current optimization of power boilers is a very important issue in research and implementation, particularly in the context of increasing environmental requirements. Combustion process requires control large number of process variables, which is usually implemented by means of the classical single-input PI or PID controllers. A large inertia and non-linearity of the combustion process necessitated the searching for new solutions in the field of control, which except better control also will allow for boiler operation optimization due to new ecological and economic conditions. The article presents the results of work of the immune optimizer SILO II installed in a distributed control system (DCS) of 650 t/h live steam power boiler. Preliminary identification tests involving the control of the amount of over-fire air, showed a strong correlation between the OFA nozzle opening level and the shape of the flame (flue gas temperature distribution). Identified relationship was basis for inference of the possibility of flame shape control to obtain optimal combustion conditions in terms of gas pollutants emission and improving the thermal efficiency of the boiler.

6

Modernizacja pieca pokrocznego do opuszczania rur stalowych po hartowaniu

Boryca J., Daniel T., Janda T., Krężołek I., Radomiak H., Szecówka L.

Hutnik, Wiadomości Hutnicze

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2000

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Vol. 67, nr 8-9

356-359

PL

Przedstawiono wyniki badań przemysłowych pieca współpracującego z podobnym konstrukcyjnie piecem hartowniczym. Wykonano wizualizację rozkładu strug, zmierzono pole temperatury i rozkład ciśnień w komorze pieca. Opracowano model nagrzewania rur i zaproponowano zmiany konstrukcyjne, prowadzące do poprawy warunków nagrzewania rur.

EN

Results of industrial testing of furnace collaborating with structural similar ardening furnace are presented. Visualization of stream distribution was carried out, thermal field and pressure distribution in furance chamber was measured. Pipe heating model was developed and structural changes leading to improved pipe heating conditions were suggested.