OPTIMUM TEMPERATURE PROFILE OF THE BLAST FURNACE

Abstract

The importance of the i31ast Furnace can be understood from the fact that in 1971 about 98 per cent of the total pig iron produced in the world was smelted in blast furnaces. ' etallurgical coke, which is produced from the good quality coking coal, is used in the blast furnace as fuel and reductant. The shortage of good quality coring coal has led the rosearche-s to think abut the methods to reduce the coke rate of the blast furnace. Many methods are: being used successfully to reduce tIi coke rate of the furnace. In this work, a, temperature profile 9 called the optimum temperature profile, has been calculated theoretically, which. corresponds to the minimum coke rate. The rates of the following reactions have been considered in the derivation-, (1) Reduction of iron oxide by carbon monoxide. (ii) Gasification, of carbon., (iii) Dissociation of limo stone. The optimum temperature profile is calculated from room temperature, at which the raw materials are charged to about 12OO C. above 1200©C the iron oxide is Assumed to bo reduced directly. iv This work9presented here, is divided in five chapters. First chapter reviews the physical chemistry of the blast furnace and the developments in the mathematical models of the furnace. Second and third chapters consist of formulation and derivation of the problem. In derivation the rates of the reactions mentioned above are considered and the mass balance around a section of small thickness of bed has been ta.ken., In chapter fourth the optimization method has been discussed and used, to obtain six differential and one algebraic equations. The computational sequence has also been given to solve these equations. the data needed in the calculation is given,, and some parameters needed in computation are calculated. Last chapter gives the results obtained. These .results are discussed *and it has been shown that the optimum temperature profile,, if employed in the blast furnace reduces the coke rate. The Runge Kutta method has been used to solve these equations. This method is given in detail in the :~ hpendix.