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一、问题的提出我厂趁2号高炉(容积294m~3)大修之机,在回收利用热风炉烟气余热时采用了回转式空气换热器,且于1982年投入使用,将助燃空气预热到250～280℃,当时在国内尚属首创。而我厂4号高炉(容积294m~3)定于1983年大修,采用哪一种烟道废气余热利用方式成为当时争论的焦点。根据2号高炉回转式空气换热器的设计计算和使用实践认为:其一,由于热风炉烟道废气的废热量大,仅预热助燃空气,排烟温度仍高达200～220℃,热回收率为38～39%,热风炉效率也只提高3%左右。同时,因为排烟温度高,给附属设备引风机的维护和使用带来困难。其二,按理论计算,燃烧1m~3n煤气仅需0.6～0.7m~3n空气,且空气热含小,从经济效益观点来看,预热空气不及预热煤气合理、合算,如在预热空气的同时又预热煤气,就达到了物尽其用之目的。
First, the issue put forward I take advantage of the 2nd blast furnace (volume 294m ~ 3) overhaul of the machine, in the recovery of hot stove flue gas waste heat using rotary air heat exchanger, and put into use in 1982, the combustion air pre Heat to 250 ~ 280 ℃, was still the first in China. And I plant No. 4 blast furnace (volume 294m ~ 3) is scheduled to overhaul in 1983, which flue gas waste heat utilization has become the focus of controversy. According to the design and calculation of the blast furnace rotary air heat exchanger No. 2 and its practice, it is considered that: firstly, since the waste heat of the flue gas of the hot blast stove is large, only the combustion air is preheated, the temperature of the exhaust gas is as high as 200~220 ° C., heat recovery The rate of 38 ~ 39%, hot stove efficiency is only about 3%. In the meantime, because of the high temperature of the exhaust gas, it is difficult to maintain and use the auxiliary draft fan. Second, according to theoretical calculations, combustion of 1m ~ 3n gas requires only 0.6 ~ 0.7m ~ 3n air, and the air heat content is small. From a economic point of view, preheating air is not as reasonable as preheating gas, The air at the same time preheat the gas, to achieve the best use of purpose.