Wyniki wyszukiwania - BazTech

1

Evaluation of thermokinetic parameters influence on pulverized coal burnout in drop tube

Paluska R., Bojko M., Horak J.

Rynek Energii

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2010

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nr 2

113-117

EN

An experimental facility and methodology of pulverized coal thermokinetic properties determination with the use of mathematical modeling is described in this paper. Thermokinetic properties as a mean for better understanding the nature of combustion process can be determined by an experiment using a Drop Tube Test Facility (DTTF) described thereinafter in this paper. The DTTF provides conditions occurring in a pulverized coal fired boiler by emulated oxygen concentration, temperature and reaction gas velocity. The DTTF presented in the paper was built recently at the Energy Research Center. Experimental data acquired from the DTTF are used in mathematical modeling using the code Fluent. The ANSYS Fluent 12.0 code can define different mathematical models of volatile evolution (devolatilization model) and char combustion (ki-netic/diffusion surface reaction rate model) to simulate coal combustion. The single kinetic rate devolatilization model as-sumes that the rate of devolatilization is of first-order and the kinetic/diffusion-limited rate model assumes that the char combustion rate is determined either by kinetics or by a diffusion rate. In this paper, a char combustion model is defined in detail with specification of a basic equation for char combustion reaction rate. Then, an equation of particle temperature is defined for char combustion. Different values of activation energy and a pre-exponential factor are defined in an equation for calculation of the rate constant by Arrhenius. Resulting values are evaluated by decrease of pulverized coal char in the drop tube in dependence of time. The process of burnout is evaluated for comparison with experimental tests.

PL

Instalacja do spalania paliw stałych z tzw. rurą opadową pozwala w prosty sposób wyznaczyć własności termokinetyczne paliw umożliwiając lepsze zrozumienie procesu spalania. Prezentowane stanowisko ba-dawcze symuluje proces spalania pyłu węglowego w palenisku kotłowym przy zadawanych warunkach brzegowych (koncentracja tlenu, poziomy temperatur, prędkości gazu). W artykule opisano rurę opadową, która w ostatnich latach została zbudowana w Centrum Badawczym Energetyki Uniwersytetu Technicznego w Ostrawie. Wyniki prowadzonych eksperymentów są wykorzystywane jako wstępne dane dla korekcji parametrów wejściowych w modelu matematycznym. Do opracowania modelu matematycznego użyto kodu ANSYS Fluent 12.0. Przedstawiono modele matematyczne uwalniania części lotnych oraz szybkości reakcji pozostałości koksowej paliwa węglowego. Wyznaczono równanie na przebieg temperatury cząstki koksu podczas spalania a także stałe kinetyczne: energię aktywacji i współczynnik przedeksponencjalny, do wyznaczania stałej szybkości reakcji w równaniu Arrheniusa. Uzyskane rezultaty zostały zweryfikowane na drodze eksperymentalnej, przy wykorzystaniu rury opadowej.

2

Experimental Measuring and CFD Modeling of Pulverized Coal Burnout in Drop Tube

Paluska R., Bojko M., Horak J.

Archivum Combustionis

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2010

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Vol. 30 nr 3

193-201

EN

An experimental facility and methodology of pulverized coal thermokinetic properties determination with the use of mathematical modeling is described in this paper. Thermokinetic properties as a mean for better understanding the nature of combustion process can be determined by an experiment using a Drop Tube Test Facility (DTTF). The test provides conditions occurring in a pulverized coal fired boiler by emulated oxygen concentration, temperature and reaction gas speed. The test presented in the paper was built recently at the Energy Research Center. Experimental data acquired from the tests are used in mathematical modeling using the code Fluent. The ANSYS Fluent 12.1 code can define different mathematical models of volatile evolution (devolatilization model) and char combustion (kinetic/diffusion surface reaction rate model) to simulate coal combustion. In this paper, a char combustion model is defined with specification of a basic equation for char combustion reaction rate. Resulting values are evaluated by decrease of pulverized coal char in the drop tube in dependence of time. The process of burnout is evaluated for comparison with experimental tests. Results acquired from the adjusted mathematical model should provide more detailed information about the combustion process in a real operation.

3

Optymalny podział środków inwestycyjnych na rozwój i modernizację sieci w spółce dystrybucyjnej

Horak J., Gawlak A., Szkutnik J.

Wiadomości Elektrotechniczne

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2006

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nr 2

10-16

PL

Przedstawiono propozycję podziału środków inwestycyjnych na rozwój i modernizację sieci w spółce dystrybucyjnej, uwzględniając zdolność przesyłową sieci.

EN

The paper presents a proposal of distribution of investment means for development and modernization of the network in distribution company, that takes intoconsideration transmission capacity of the network.

4

TRANSCAT DSS architecture and modelling services

Horak J., Unucka J., Stromsky J., Marsik V., Orlik A.

Control and Cybernetics

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2006

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Vol. 35, no 1

47-71

EN

The main goal of the TRANSCAT project is to create an operational and integrated comprehensive Decision Support System (DSS) for optimal water management of catchments in borderland regions. The analysis of system requirements was followed by the analysis of possible architecture of the complex system and its appropriate design. The core of the proposed system (ETRA GIS) contains gis-Toolkit, web server, DBS, database interface, web services application interface and remote components. The system utilises selected software tools of hvdrological and hvdrogeological modelling (HEC-HMS, ModFlow, GRASS GIS modules). The special wrappers for each of the model were developed, enabling communication among models. Decision-making is supported by integrated decision applications (mDSS, Mediator, ProDec, BarTend, ArgWar) facilitating mainly the process of evaluation of a wide spectrum of indicators and the process of decision-making. The core of the system utilises a database with special design. The object part of the database represents a data warehouse with multidimensional structure. Implementation of TDSS was undertaken in Bela/Biala Glucholaska (CZ/PL), Pasvik (NO/RUS), Sumava (CZ/D), Mesta/Nestos (BG/GR) and Guadiana (P/ESP) pilot areas, where also respective models were calibrated.