CLOSED CIRCUIT CEMENT GRINDING

АСУ ТП  процесса помола цемента

Process automation solution for closed circuit cement grinding is described on the basis of the example of Dyckerhoff facility.

The automation solution controls all the elements of cement grinding ball mills: the main electric drive of the ball mill; the controlled electric drive of the separator; the controlled electric drive of the separator fan; the controlled electric drive of the separator suction unit; the controlled electric drive of the ball mill aspirator; the electric drive of the silo aspirator; the electric drive of the belt bucket-elevator; the electric drive of the Fuller pneumatic screw pump; the controlled electric drives of the feed disks, air hose filter, and dozing system

PROCESSES AUTOMATION PURPOSES

  • Ensures automatic control over cement grinding in ball mills No 4 and 5;
  • Maintains the predetermined parameters of cement milling, such as temperature, pressure, and suction;
  • Sends instant messages about technological parameters and checks the state of the equipment;
  • Readjusts the technological process depending on the cement make.

 

PROCESS AUTOMATION STRUCTURE

The automation solution is based on Simatic PCS7 which makes part of S7-400 programmable controller and WinCC-based workstation. The system also includes Simatic Net industrial networks: Profibus and Industrial Ethernet.

This is a decentralized two-tier multifunctional system.

The decentralized system is based on the following principles:

In terms of control levels:

Top level - operator’s station that performs centralized and operational control over the facility, visualizes industrial processes, and provides operating personnel with up-to-date information;

Lower level - programmable logic controller that collects and processes information, and issues commands to mechanisms;

In terms of location:

Operator’s panel;

Control cabinet with a PLC;

Distributed peripheral cabinet ЕТ200М;

The controlled mechanism

 

PROCESSES AUTOMATION FUNCTIONS

Basic functions of industrial automation:

Determines, adjusts, and indicates the technological parameters of the processes;

Determines, adjusts, and indicates the location of the mechanisms;

Selects operating modes of the cement mill;

Keeps record of major technological parameters;

Archives average technological parameters per hour and per shift.

Visualization system and its functions:

  • Visualizes all the operating modes of the ball mill;
  • Displays tables with technological formulations
  • Shows the state of electrical devices and other industrial equipment

Control functions:

The automation system enables different control modes for electric drives and actuators:

  • Manual control when the mechanisms are tested;
  • Remote control from the display;
  • Automatic control.

Control modes are chosen on the computer.

Safety functions (blocking)

  • Electric drives are stopped when the “Emergency” button and the conveyor lanyard switch are activated.
  • Electric drives equipped with rotation sensors can be stopped if the sensor fails to deliver any signal after the drive is started.
  • Once an electric drive is blocked, other connected drives can be stopped as well.

 

Communication functions:

The system visualizes the current technological process on the display with multiple screens.

The current progress is displayed as numeric fields on the screen showing the technological scheme. The fields contain information about the predetermined and actual temperature of the raw material, the amount of the material fed, and the drive load.

The system monitors the process of industrial control and reacts when something of this happens:

  • The technological parameters exceed the predetermined values (warning and emergency values);
  • The operator does something unacceptable.

 

The system lets operators view and edit the settings of warning and emergency signals, as well as temperature regulations. Access to this information can be protected with a password to avoid unsolicited use.

Implementation experience:

Object
Name of workWork
Year
Ivano-Frankovskcement, Ivano-Frankovsk region, Ukraine
Cement mill №6. ACS TP. Projecting
Volyn-Cement PJSC, Zdolbunov, Ukraine
Cement mill №8. Mill control panel. ACS TP. Application software, commissioning
Cement Ltd, Odessa, Ukraine
Cement mills №4, 5. ACS TP and electric drives automatic control system for the close-cycle cement grinding. Projecting and software design, low-voltage devices manufacturing and supply, assembling, testing and commissioning
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