セメント粉砕閉回路の静特性に基づく制御系設計指針 粉砕閉回路のロバスト制御に関する研究（第２報）

Abstract

It is known that the typical control system based on BE electric power, which has been applied in many cement grinding plants, has some problems. Other types of controls therefore have recently been proposed. They require both to stabilize the process and to improve the product quality against the changes in clinker grindabilty. The authors have already constructed the transfer function model from population balances of the process. The purpose of this paper is to present an optimal control strategy based on the steady-state characteristics. Firstly we criticized several conventional control methods. For instance, it was quantitatively confirmed that the BE electric power control system could not regulate the product property and the multivariable one by manipulating the classifier cut size could not keep the product quality as well as its quantity simultaneously against the feed change in grindabilty. Consequently we have proposed a hierarchy control system, consisting of the two stages. The higher one is to determine the product set-point values and the lower one is to control the stability and the product quality. In this system, when the grindability becomes low the decrease of the product quantity can be prevented by changing the set point of the product quality. This system has also an advantage of avoiding the mill choking. As to the detection of gindability it was suggested to estimate it by measuring the product quantity and quality (specific surface) simultaneously, or practically mill discharge quality only.