ABSTRACT:

An LD converter can produce 200- 400 tons of steel in 20- 25 minutes. However, the fast dynamics of the process makes accurate manual control very difficult and necessitates computer control.

In this report, first a study of LD process dynamics has been presented; the influences of various inputs, disturbances and control variables on control objectives have been clearly identified.

A critical study of 14 different static and dynamic control schemes/models of LD converters has been done. The most important goal attained in this work is a dynamic digital simulation of LD converter on IBM 360/44. A special integration algorithm requiring only 5 mnltiplication and 3 addition operations with very little memory requirement and computation time has been developed to solve the differential. A timer routine has been used to find the time required for each section of the program. In its fina1 form, the program takes merely 20-25 seconds for complete simulation of 30 minutes heat (one blowing operation). However, an additional one minute is required to plot the results in an elegant graphical form, if desired. The graph shows complete time history of bath composition, temperature, oxygen distribution (among C, Si and Fe), weight of slag and its constituents. Complete details of simulation routines and derivation of integration algorithm are included in this report.

Finally, a study of instrumentation and various LD computer control systems has been presented. Therein the need for computer control, various digital computer functions and subsystems to be interfaced with it have been discussed in detail. The type of computer, peripherals and sensors required have been briefly discussed. A list of new sensors proposed till todate has also been included.

In a nutshell, this work includes several diversified aspects of "computer control of LD process of steelmaking," such as metallurgical, chemical, control, instrumentations, computer hardware and computer software.

Complete report in Adobe Acrobat format.