For the automatic control of hot metal temperature, an advanced computer control system was developed on the basis of the new mathematical model of blast furnace described in the other paper.
The characteristic features of the system are as follows:
(1) The parameters of the model are adjusted in advance by the adaptive feedback of actual operational data.
(2) Through the forward simulation of the process by the model, the hot metal temperature is predicted.
(3) The oil injection rate required for the control is derived from the difference between the predicted hot metal temperature and the aimed one. By examining the control characteristics of the system through the simulation, it is confirmed that the system is effective for the stable blast furnace operation.
With this system, the automatic control has been carried out at Kokura No. 2 BF since 1977 and the fluctuations of the hot metal temperature and the silicon content have been decreased. As the result of the control of the thermal condition, the hot metal temperature could be lowered by 15°C, which contributed to the decrease of fuel ratio by 4 kg/t-pig.
