The Blast Furnace Mathematical Modelling: Looking into the mathematical interpretation of the Physico-Chemical and thermal dynamics of the Blast Furnace

by Gurprit Singh

A Blast Furnace is a reactor which is charged continuously and tapped intermittently. But the way technology has improved, bigger and the most modern furnaces are almost tapping continuously. The largest furnaces can tap even 10,000 tonnes of hot metal every day. The solids like Coke, Sinter, Iron ore, pellets, limestone, quartzite and sometimes even BOF slag and Manganese ore are charged into the furnace from the top using a double bell system in the old furnaces and by bell-less charging in all the modern furnaces. As the Raw materials descend from top to bottom, these come into contact with the ascending hot gases from the tuyere zone upwards, as the coke burns in the raceway in a blast furnace. Thus, the heat is transferred from hot gases to the colder raw materials and these get heated up. The volume of the raw materials expands with increasing temperature and the increase in the diameter of Blast furnace proves useful to accommodate this expansion. Once the materials are sufficiently heated up and the Carbon Monoxide and Carbon reduces the iron ore, the charge starts to fuse and form metal and slag and now it contracts in volume. Thus, the diameter of furnace needs to be reduced accordingly. The waste gases are collected at the top and liquids like slag and molten iron at the bottom. The section is reduced at the top since the collection of gases in a vast area is difficult. The strength and quality of the available coke determines the effective height of the furnace. The BF height depends normally on the strength of the coke available in India. After all, the column of charge material is so heavy and it should not pulverize the coke else the permeability or the passing of gases through the descending column would come to a halt. So, normally any increase in the effective volume is achieved through the increase in the cross section of the furnace keeping the furnace height practically the same. Of course, once design phase is over, one cannot change a furnace’s dimensions without a complete blow-out. In this book, before detailing the mathematical modelling a few basics of chemistry and metallurgy have been introduced. The fundamentals of Chemistry and Thermodynamics are first covered. There is a need to know about Physical Metallurgy including the very well-known Iron-Carbon Equilibrium process. Next we learn about the Physico-Chemical and the thermal Principles of Blast Furnace Metallurgy. Chapter 4 is the most relevant one and the whole book revolves around it. It is named the Blast Furnace Calculations. After that Mathematical Models have been discussed. In another Chapter the RIST Model and C-DRR diagram are specially touched upon. The Blast furnace is a dynamic process and use of computers is a prerequisite for analyzing the Blast Furnace process in real-time. This has also been discussed. Lastly, we discuss about the latest Developments in Blast Furnace Technology, in general. Students studying B. Tech and higher levels may find this book interesting since this book is not written in a very traditional way. It has been the endeavor of Author to keep things simple and understandable. Working engineers may also find it useful.

492 pages, Kindle Edition

Published March 14, 2021