Author: Andrey Ushchapovsky
Paper mill dispatching. In June 2017, Artezia put into operation an automatic control system for the steam supply module for the paper machine.
The drying part of the machine consists of 12 drying cylinders, which are divided into groups. Steam of a given pressure must be supplied to each group of cylinders.
The steam supply system is a complex installation, which consists of the following units:
- steam input - performs the function of accounting for steam supplied to the machine;
- reduction unit - reduces the pressure of steam coming from the boiler house of the enterprise, to a predetermined value;
- steam supply to the cylinders - the steam pressure setting depends on the type of paper that the machine is currently producing.
The appearance of the installation is shown in the figure:
In addition to these nodes, the system includes:
- secondary boiling vapor separator, in which steam is separated from the condensate formed during the operation of the system;
- a condensate station that uses a pair of mechanical pumps to return condensate to the boiler room.
The condensate station also includes an evaporative cooler, in which the residual steam energy is used to heat cold water for the needs of the enterprise.
The control system maintains a predetermined pressure in the secondary boiling vapor separator, which should not exceed the steam pressure supplied to the machine cylinders. The technology demands it.
The condensate station has a unique algorithm for accounting for condensate flow.
The structure of the control system consists of two boards - a control board and an indication board. A programmable logic controller is installed in the control panel, in which algorithms for controlling the steam supply system, electrical equipment for receiving signals from sensors and sending commands to the executive equipment are implemented. The control system can be configured and monitored from the local touch panel.
The display panel is designed to show the pressures with which steam is supplied to the cylinders of the machine and the pressure to the steam separator. The indication board was made to ensure that operators could quickly obtain the necessary information.
The front panels of the boards are also equipped with LED lamps to show the operating status of the control system and emergency buttons to stop the steam supply to the machine in case of possible unforeseen situations during paper production.
For remote control and monitoring of the operation of the control system, a dispatching system was developed, which runs on a miniserver myBOX:
The miniserver is installed in the control panel and accessed via the local network - you just need to enter the server's IP address in the browser and the user will see a page that shows information about the system operation:
To display information, a new approach was used in the development of dispatching systems, which is called High Performance HMI, which provides for the display of information, and not ordinary data.
This approach is new and unusual for operational personnel. Given this, the data feed was made in the form of a mnemonic diagram of the technological process:
The dispatching system, in addition to monitoring the operation of the control system, provides the ability to customize the operation of the system. Of course, settings are available only to authorized personnel. In addition, the system archives all user actions. Thus, it is always possible to analyze what has been changed and by whom it has been made.
Access to the dispatching system is carried out as from a desktop computer:
and from a smartphone:
To do this, a WiFi router was installed and now the staff has the ability to control the parameters while being within the range of the network. The range of the network is enough to cover the distance in the length of the car.
The introduction of the control system made it possible to adjust the temperature regime of the paper machine, which affects the quality of the paper and increase the speed of the machine.
The dispatch system allows the personnel to get information about the operation of the machine faster, quickly respond to situations and make decisions on further actions faster.
