Kotel bloku 200 MW s předehřevem vzduchu recirkulací horkého vzduchu

Abstract

The master thesis is dealing with recirculation of hot air proportion back in front of air –heater in boiler of a 200 MW unit incinerating black coal. The thesis introduction refers to method of combustion products’ temperature regulation by means of air recirculation. It’s also focused on implications of combustion products’ temperature decrease below acid dewpoint and on ways of its measurement. There are also described and shown two variations of carrying out the recirculation. The calculation part is first of all looked into the stoichiometry, generating heat and determination of the thermal loss of the boiler and its efficiency. Thermal balance is determined for both variations of implementation the air recirculation and the required amount of recirculated air is calculated too for reaching required parameters. According to the balancing results there’s assessed an effect of preheating on a fan self – consumption and then the most efficient variation is opted. Suitable fans from manufacturers’ catalogues are selected for this variation and a diagram of combustion products’ temperature regulation is projected. The drawing part demonstrates the way of placing the recirculating fan and air ducts in a pipe system of the boiler house.