Nvestigation of the influence of fuel con-sumption and geometric dimensions of the refractory blocks of the blast furnace nozzle on the blast-heating temperature

At present, the average temperature of hot blast on blast furnaces in Ukraine has significantly decreased and is about 1000°C. This is not related to the possibilities of its heating, but is caused by the shortage and cost of natural gas, the irregular feed of raw materials and thеir quality. An increase in the blast-furnace heating temperature in blast-furnace production is one of the effective ways to reduce the expensive coke rate and improve the parameters of the blast furnace operation. The common ways to increase the blast temperature, such as enrichment with natural gas or oxygen, are very expensive, and therefore are not currently in practice at industrial enterprises. Due to that, alternative low-cost ways to increase the blast temperature and methods for evaluating their effectiveness become relevant. The influence of the geometric dimensions of the air heater nozzle and the fuel consumption on the blast temperature have been analyzed. For this, a two-dimensional mathematical model of the operation of the blast air heater was used. The model results from the operation of the air heaters at the blast furnace No. 3 of «Ilyich iron and steel works». An increase in the blast furnace gas consumption by 30% makes it possible to increase the blast temperature by 137°C. In this case, heat losses with outgoing gases increase by 2,6%. However, an increase in blast furnace gas consumption is restricted by the following factors: blast furnace gas proper re-serve at the plant, the capacity of the burner, the operational features of the fan for supplying air and exhaust gases. The change-over from the standard 6-gang block with a 41 mm cell size to the same block with a 30 mm cell size makes it possible to raise the temperature by 33°C due to the intensification of heat exchange from the combustion products to the nozzle and to reduce heat losses with the outgoing gases. In this case, owing to the volume reduction of the nozzle solid body, its thermal power will decrease