Wyniki wyszukiwania - BazTech

1

HTAC Boiler Fired with Pulverized Coal for Ecologic and Efficient Electricity Production

Schaffel N., Szlęk A., Mancini M., Weber R.

Archivum Combustionis

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2008

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Vol. 28 nr 1-2

105-112

EN

The authors propose a concept of HTAC technology application to the power boilers fired with pulverized coal. So far, HTAC technology was implemented mainly in industrial furnaces fired with gaseous fuels or light oils. In order to investigate the HTAC boiler, several series of numerical simulations have been performed using FLUENT code. A specially emphasis was placed on the main technical and ecological issues that must be considered wherever HTAC technology would be applied in real power station boilers fired with pulverized coal. Mathematical model validation has been done against the experiment performed at IFRF. As an effect of several numerical investigations a final design of the HTAC boiler has been found and the results are presented and discussed in this paper. The proposed HTAC boiler features following major advantages: small size, low harmful substances emission, mainly NOx, high and uniform heat fluxes and very simple construction of the burners. Overall, the present study confirmed that HTAC technology could be a practicable, efficient and clean technology for fossil fuel fired boilers. However, it has to be pointed out that the investigated boiler is only still a concept and before any industrial application much researches have to be done.

2

Self-ignition of methane in high temperature air

Werle S., Wilk R.

Chemical and Process Engineering

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2007

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Vol. 28, z. 3

399-412

EN

The paper presents the results of experimental and computational studies on the methane self-ignition process in high-temperature air. The computational studies are based on mass and energy balance equations and experimental data. The real temperature T[real], the ignition delay time T and the increment of temperature [Delta T] are assumed as parameters characterizing the process of self-ignition under conditions of superheating of the air. In order to achieve the minimum ignition delay time T (the maximum reaction rate), the maximum of the real temperature [T real] and maximum of the increment of the temperature [Delta T], the air has to be preheated to a temperature o [T air] about 850-875 C[degrees].

PL

Przedstawiono wyniki badań eksperymentalnych oraz obliczeń dla procesu samozapłonu metanu w powietrzu ogrzanym do wysokiej temperatury. Obliczenia oparto na równaniach zachowania masy i energii oraz na wynikach badań eksperymentalnych. Przyjęto, że parametrami charakteryzującymi proces samozapłonu są rzeczywista temperatura [T real], przyrost temperatury [Delta T] i czas zwłoki samozapłonu T . Stwierdzono, iż w celu osiągnięcia minimalnej wartości T (maksymalnej szybkości reakcji), maksymalnej temperatury rzeczywiste [T real] i maksymalnej wartości przyrostu temperatury [Delta T] powietrze powinno być podgrzewane do wartości [T air] około 850-875 [stopni] C.

3

Preliminary Studies of HTAC Technology Applications in Boiler Fired with Pulverized Coal

Schaffel N., Szlęk A.

Archivum Combustionis

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2007

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Vol. 27 nr 1-2

55-67

EN

High Temperature Air Combustion (HTAC) technology is probably the most important achievement of combustion technology of recent years. lt has been successfully introduced in hundreds of industrial furnaces which is extraordinary fast progress as for energy technology. In these furnaces was observed significant reduction in fuel consumption and harmful substances emission. Although all applications are limited to industrial furnaces, HTAC technology should give significant advantages when applied in boilers. In this paper, the authors analyze a simple design of a boiler operating on HTAC technology fired with pulverized coal. The calculations were done using the commercial CFD code Fluent (version 6.2.16). Selection of the mathematical models is based on the simulation of the IFRF experiment called HTAC 99, which was one previous work of the authors [l]. lt has been found the exact geometry of the combustion chamber, location of the burner block in the boiler and distance between individual burners. Finally, calculation with the investigated design of the boiler operat ing with HTAC conditions fired with pulverized coal has been done. The results of a series of mathematical modelling will be presented and discussed in this paper. This work demonstrated an extremely attractive technology for efficient and environmentally friendly combustion.

4

Ignition delay and combustion time of methane in hot compressed air

Szlęk A.

Inżynieria Chemiczna i Procesowa

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2006

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T. 27, z. 4

1547-1554

EN

The influence of air excess ratio, oxygen concentration, pressure and temperature on ignition delay time and combustion time have been analyzed for the mixture of methane, air and water vapour. It has been found that combustion time of methane in the range of pressures and temperatures typical of operation of gas turbines is comparable with expansion time in turbines. The main factor affecting ignition delay and combustion time is oxygen concentration.

PL

Badano wpływ nadmiaru powietrza, stężenia tlenu, ciśnienia i temperatury na czas zwłoki zapłonu oraz czas spalania metanu w mieszaninie z powietrzem oraz parą wodną. Przedstawione wyniki wskazują, że czas spalania metanu w zakresie ciśnienia i temperatury typowym dla turbin gazowych jest porównywalny z czasem ekspansji w turbinach gazowych. Stwierdzono także, że czynnikiem wpływającym w największym stopniu na czas zwłoki zapłonu i czas spalania jest zawartość tlenu w utleniaczu.

5

Badania eksperymentalne procesu samozapłonu metanu w wysokopodgrzanym powietrzu

Wilk R. K., Werle S.

Archiwum Spalania

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2006

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Vol. 6, nr 1-4

1-11

PL

Spalanie w technologii HTAC jest uważne za jedno z największych osiągnięć techniki spalania ostatnich lat ze względu na możliwość zwiększenia sprawności energetycznej oraz redukcję emisji NOx i CO. W pracy przedstawiono wyniki badań eksperymentalnych procesu samozapłonu metanu w wsyokopodgrzanym powietrzu. W tym celu zaprojektowano i skonstruowano specjalne stanowisko badawcze. Przeanalizowano między innymi wpływ temperatury podgrzania powietrza i udziału objętościowego metanu w mieszance palnej na czas reakcji samozapłonu oraz na przyrost temperatury reakcji.

EN

High Temperature Air Combustion Technology is one of the biggest achievements of combustion technologies in the last few years. Owning to it we can improve energetic efficiency and reduce of NOx and CO emissions. In this paper experimental tests of gas autoignition process at high - temperature oxidizer have been carried out. For this purpose the special experimental stand was designed and built. The maximum temperature increment and the shortest time of reaction are at the range of temperature 850 ± 950 °C. This value of temperature can be proposed as a autoignition temperature in case of HTAC. Others conclusions relating to experimental investigations of methane autoignition process at high-temperature oxidizer were also drawn.

6

Influence of recirculation rate on co and no emission in HTAC combustion technology with natural gas

Malczyk K., Szlęk A.

Archiwum Ochrony Środowiska

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2005

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Vol. 31, no. 3

37--48

EN

HTAC (High Temperature Air Combustion) technology is one of the most important achievements in combustion engineering of recent years. The main idea of the technology is to organize combustion in such a way that reaction takes place in almost whole volume of combustion chamber with very uniform gas and temperature field. It can be done by preheating air above the ignition temperature of fuel, separation of air and fuel nozzles and by high recirculation inside the combustion chamber. Uniform and moderated temperatures result in very low thermal NO emission, and on the other hand, long enough residence time in the chamber results in low CO and incomplete products emission. In this paper authors present simple mathematical model which allows for estimation of influence of air temperature and flue gas recirculation rate on final emission on NO and CO.

PL

Technologia HTAC (High Temperature Air Combustion) jest jednym z najważniejszych osiągnięć w technice spalania w ostatnich latach. Jej ideą jest taka organizacja procesu spalania, aby reakcja zachodziła w całej objętości komory spalania przy wyrównanych profilach temperatury i koncentracji. Może to być zrealizowane poprzez podgrzanie powietrza powyżej temperatury zapłonu paliwa, oddzielenie dysz powietrza i paliwa i wysoką recyrkulację spalin wewnątrz komory spalania. Wyrównana i umiarkowana temperatura we wnętrzu komory pozwala na osiągnięcie niskiej emisji NO a z drugiej strony dostatecznie długi czas pobytu owocuje niską emisją CO. W niniejszej pracy autorzy przedstawiają model matematyczny pozwalający ilościowo ująć wpływ temperatury powietrza oraz stopnia recyrkulacji na końcowa emisję NO i CO.