Some Studies on the Behaviour of Gas in Blast Furnaces
Yoshio Imao, Shigeru Mizuno
It is very difficult to examine the behaviour of gas in blast furnaces not with a model but with an actually operating blast furnace.
However, a German-type gas-sampling equipment was installed on the shaft of No. 1 blast furnace in Kokura Steel Works, Sumitomo Metal Industries, Ltd., so it was possible to examine the behaviour of gas in the shaft with the equipment. While there was no such equipment on No. 2 blast furnace, so that a simplified-type gas-sampling equipment was installed and the behaviour of gas in the blast furnace was examined.
Results obtained were as follows:
1. The distributions of CO2, gas temperature and ascending gas velocity etc. were different for each furnace.
2. The behaviour of gas changed in company with combination of burden.
3. The reducibility of each part in the blast furnace changed in company with combination of burden. The reducibility of the lower part with 100% self-fluxing sinter burden was higher than that with 100% raw iron ore burden.
4. About 25% of CO in the gas-passing through the part where the gas-sampling equipment had been installed was consumed for carbon deposition and about 5% was consumed for reduction of ore between the part and the top.
5. The behaviour of shaft-gas in abnormal state was roughly known, e.g. the CO2 content in the ascending gas increased during the hanging.