OCR Text |
Show 3 Fig.l shows the construction of regenerative system. The system consists of a pair of burner, regenerator, reversing valve, air blower, and exhaust fan, together with a control system to regulate these components. The heat storage material, in which the high temperature exhaust and reciprocally the supply air passes through for making the heat exchange by aid of the heat storage material. 1.2 ENERGY SAVING CHARACTERISTICS Fig.2 shows the relation of furnace temperature and pre-heated air temperature. The pre-heated air temperature is 1100°C at the furnace temperature of 1300t, and is 800t at the furnace temperature of l000°C, therefore, the air is heated into approx., 80% of the furnace temperature. Although this value varies depending on the air ratio and suction rate of in-furnace gas, it is much higher value comparing with recuperator. Fig.3 shows the relation of pre-heated air temperature and energy saving rate, where the operation above 1200°C provides the energy to be almost half. Further, 20 to 30 % more more saving of energy may be available, as for the conventional furnaces using the recuperator. P 1200 ~-~-~----r--~--' 100 , ~ Inpur300~w.aj'1 rrario1 ~ 1000 r- ! E ~ 800 80 Input 300kW. air ratio 1.1 ~ - <f!- ac:: :; 60~ - ~>a . 40 ~ ~ - 600 iii . c:: W 20 400~-~-~-~--~-~ 900 1000 1100 1200 1300 1400 0 Furnace TemperallJre 't 900 1000 1100 1200 1300 1400 Fig.2 Furnace Temp. and Pre-heated air Temp. Furnace T~ure 1: Rg.3 Furnace Temp. and Energy Saving 2. FDI COMBUSTION PRINCIPLES AND STRUCTURE 2.1 FDI COMBUSTION PRINCIPLES In case of burning the fuel, such as natural gas, NOx is mainly generated by the process as described in Zeldvich's mechanism. Effective methods for low NOx combustion are to reduce the |