A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Effective automation of closed circuit bucket elevator mills for cement
The operation of grinding plants with low staff levels is efficient when the control room personnel are to the same extent freed from formalizable duties. Tools must be made available which make creative work possible for the operators. Automation cannot compensate for deficiencies in process technology and equipment engineering. For the automated operation of closed circuit bucket elevator mills, complicated and expensive expert systems are in competition with simple control strategies that can be effected in the existing programmable logic controllers (PLC). Raw material screening and furnace operation and demixing during clinker storage and during transport repeatedly lead to changes in the feed properties and hence to changes in the grinding behaviour in grinding plants. Particularly in the maximal loading range of grinding plants this leads to fluctuations in the recycle volume despite constant feed rate and constant classifier revolution rate. As early as 1978, Hiettler reported a control strategy that takes account of this situation. The basis is the operating characteristics of the mill tube and classifier. It is demonstrated how, with the modern possibilities afforded by a PLC, not utilised PID controllers can be activated and parametrised so that closed circuit bucket elevator mills can be started in accordance with start and target value settings and run up in accordance with transition functions. With fixed settings, transition functions (start-up and blend change) are completed within 15 - 30 minutes. Even during start-up of the grinding plant, target finenesses are to a rough approximation attained during the execution of the transition functions. Irregularities during the controlled operation indicate inadequate control of the grinding plant. The implementation of the proposed control strategy in an existing PLC can be carried out using the in-house measurement and control personnel with responsible involvement of the process engineer.
Effective automation of closed circuit bucket elevator mills for cement
The operation of grinding plants with low staff levels is efficient when the control room personnel are to the same extent freed from formalizable duties. Tools must be made available which make creative work possible for the operators. Automation cannot compensate for deficiencies in process technology and equipment engineering. For the automated operation of closed circuit bucket elevator mills, complicated and expensive expert systems are in competition with simple control strategies that can be effected in the existing programmable logic controllers (PLC). Raw material screening and furnace operation and demixing during clinker storage and during transport repeatedly lead to changes in the feed properties and hence to changes in the grinding behaviour in grinding plants. Particularly in the maximal loading range of grinding plants this leads to fluctuations in the recycle volume despite constant feed rate and constant classifier revolution rate. As early as 1978, Hiettler reported a control strategy that takes account of this situation. The basis is the operating characteristics of the mill tube and classifier. It is demonstrated how, with the modern possibilities afforded by a PLC, not utilised PID controllers can be activated and parametrised so that closed circuit bucket elevator mills can be started in accordance with start and target value settings and run up in accordance with transition functions. With fixed settings, transition functions (start-up and blend change) are completed within 15 - 30 minutes. Even during start-up of the grinding plant, target finenesses are to a rough approximation attained during the execution of the transition functions. Irregularities during the controlled operation indicate inadequate control of the grinding plant. The implementation of the proposed control strategy in an existing PLC can be carried out using the in-house measurement and control personnel with responsible involvement of the process engineer.
Effective automation of closed circuit bucket elevator mills for cement
Wirksame Automation von Becherwerksumlaufmühlen für Zement
Clemens, P. (author)
2002
7 Seiten, 7 Bilder, 5 Quellen
Conference paper
English
Anfahrsteuerung und -regelung , Automatisierung , Betriebsverhalten , Einschwingvorgang , Elevator (Becherwerk) , Expertensystem , geschlossener Kreisprozess , Klassiermaschine , Korngrößenverteilung , Kugelmühle , Mahlanlage , Mahlfeinheit , Mahlwerk , Personalbedarf , PID-Regler , programmierbare Steuerung , Prozesssteuerung und -regelung , Zementindustrie
Effective automation of bucket elevator mills for cement
| British Library Online Contents | 2004