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The impact of unevenness and instability of flue gas temperature on the technical condition of gas turbine blades

Błachnio J., Kułaszka A., Perczyński J.

Journal of KONES

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2018

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Vol. 25, No. 2

45--51

EN

Gas turbines are used in the power sector, aviation, pump houses, and other technical systems. Such a broad range of application is associated with favourable indicators: high power, rather low weight per unit of power, significant efficiency, as well as high durability. All of these indicators greatly depend on the combustion chamber flue gas temperature. It is important for the flue gas temperature to be uniform around the turbine perimeter and stable over time. This condition is extremely important also in the case of frequent temperature variations associated, e.g. with a variable operating range of a manoeuvre aircraft turbojet engine. The paper analyses the causes for the unevenness and instability of combustion chamber flue gas temperature. The impact of the fuel quality, the technical condition of the fuel supply system, as well as the operating conditions of the combustion chamber-turbine assembly was shown. The issues regarding the presence of various types of damage to turbine elements, their blades in particular, were defined. The main cause behind the damage is the unevenness and instability of flue gas temperature, resulting in the presence of overheating, creeping, thermal fatigue, high-temperature corrosion of blade material. The forms of that damage, especially the first turbine stages, were presented. Blade material microstructure test results showed increased layer thickness, grain-size, and especially, adverse modification of the strengthening γ' phase in the temperature function. It was concluded periodic diagnostics of turbine blades with the optical method enables the non-invasive evaluation of their technical condition and drawing conclusions in terms of their durability.

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Effects of operating conditions on DeNOx system efficiency in supercritical circulating fluidized bed boiler

Błaszczuk A., Nowak W., Jagodzik S.

Journal of Power Technologies

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2013

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Vol. 93, nr 1

1--8

EN

The purpose of this work was to determine the impact of a operating conditions on the deNOx system efficiency.in a 966MWth supercritical circulating fluidized bed boiler. Experimental tests were carried out on a full-scale DeNOx system installed in the world’s largest once through supercritical circulating fluidized bed boiler. In this work, the effects of the following parameters were studied: flue gas temperature inside the separators between 636°C and 845°C, relative ammonia mass flow over the range 0.22-1.00 and three relative values of O2 concentration (i.e. 0.94, 1.0 and 1.13). The efficiency of deNOx system increases (ca. 53%) with increasing relative ammonia mass flow. A maximum DeNOx system efficiency (ca. 70%) was achieved at flue gas temperature in the range from 720°C to 790°C. In the case of all unit loads, deNOx system efficiency from 36% to 70% was observed and performs a standard emissions relate to permissible concentration of NOx in the flue gas.

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Wpływ przegrzewu wtórnego na własności układu STIG

Jesionek K., Chrzczonowski A.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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2005

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z. 211

101--106

PL

Wtrysk pary do komory spalania turbinowego układu gazowego (układ STIG) umożliwia uzyskanie zmiennego - w szerokich granicach - wskaźnika skojarzenia oraz podniesienie sprawności i elastyczności układu kogeneracyjnego. Maksymalne sprawności układu STIG w wersji podstawowej są ściśle zależne od temperatury spalin na wlocie do turbiny, która jest ograniczona termowytrzymałością materiałów konstrukcyjnych. Jedną z możliwości podniesienia sprawności przy ograniczonej temperaturze spalin jest zastosowanie spalania sekwencyjnego. W pracy przedstawiono niektóre rezultaty obliczeń układu gazowego STIG z wtórną komorą spalania. Wynika z nich, że spalanie sekwencyjne umożliwia znaczne poprawienie własności energetycznych układu STIG a istotne znaczenie ma podział spadku entalpii na części nisko- i wysokoprężną turbiny.