Automation and dispatching systems for boiler houses ensure efficient and safe operation of these facilities. They allow real-time assessment of the serviceability and effectiveness of equipment, timely shutdown in emergency and pre-emergency situations. When servicing a number of boiler houses located at a considerable distance from each other, all the necessary information can go to a single control room, which significantly reduces maintenance costs.
Tasks
The main purpose of the boiler automation and dispatch system is:
- management of starting and stopping boilers (including emergency situations);
- automatic and manual power adjustment of boilers;
- cascade control of the total heat capacity (starting the second boiler from the reserve, if the first is not enough to maintain the required temperature at the consumer, then turning on the third, transferring the spent boiler to reserve);
- regulation of the characteristics of the coolant at the outlet of the installation;
- launch of backup equipment in case of failure of the main one;
- enable alarms and send messages;
- transition to an energy-saving mode and the implementation of other program settings (maintaining the temperature of the coolant depending on the street temperature, according to a predetermined schedule, taking into account the day and night mode).
general description
Modern boiler house dispatching systems are built in the form of a set of unified modules, the main elements of which are:
- power cabinet;
- automation cabinet;
- control and management panel (dispatcher panel);
- electrical actuators;
- sensors.
The equipment and technical specifications of this equipment depend on the technological solution of the heating system, manufacturers' recommendations, and automation features. The collection, processing of data, the formation of working algorithms and control teams are combined into functional groups and distributed among controllers and modules.
Information from all devices goes to the control panel and can be displayed on the dispatcher's computer. To visualize and set parameters, special software is used (SCADA, APROL and others).
Controllers
Controllers for automation and dispatching boiler rooms are used with programmable logic. Their feature is that they serve as independent devices, have universal inputs and outputs (which ensures their high interchangeability).
The line of programmable logic controllers is very diverse in functional, technical and design characteristics. Thanks to their use, verification and adjustment of cabinets is facilitated, and high reliability of all equipment is ensured.
Functions
Dispatching a boiler house performs the following functions:
- Monitoring of sensor readings: temperature (T) and water pressure (p) in the forward and reverse lines; T and p at the inlet / outlet of the boiler; p fuel in a gaseous or liquid state; T and p of the supply and return water of the heating circuit; T and changes in the composition of the surrounding air in the boiler room and on the street; liquid level in the make-up tank.
- Monitoring of instruments and equipment: state of differential pressure sensors on circulation pumps; automatic or manual operation of boilers and pumps; the transition of mechanisms designed to move the regulatory body into various states (“open”, “closed”); setting the boiler to the “on”, “off” or “emergency” state.
- Management: emergency shutdown of boilers, power off automation; closing the shut-off solenoid valve to shut off the supply of liquid or gaseous fuel; starting in summer, once a day, network pumps and a heating control valve; switching on the second (third) boiler with insufficient thermal power, switching off the used one - rotation on operating time; control of the make-up and circulation pump, as well as the valves.
- Protection of the elements of the technological scheme of the installation in the following situations: drop in p in the boiler circuit as a result of coolant leaks; increase p and T of water at the outlet of the boiler in excess of permissible; burner inoperability; fire or increased gas contamination (exceeding the MPC for carbon monoxide or methane).
- Alarm: emergency; pre-emergency; sending SMS messages on the GSM channel; remembering the cause and exact time of the accident.
Power control cabinet
The control cabinet is used for switching power circuits of pumps, boilers, electric motors, valves and other equipment. It is equipped with the following devices:
- control mode voters for selecting a command source;
- signal lamps (light indication of equipment operation);
- switching elements of manual and automatic control (switches, contactors, thermal relays and others).
Structurally, it is made in the form of a metal cabinet in a wall or floor design, on the back wall of which mounting panels are attached with the above devices.
Automation cabinet
The complete set of the automation cabinet depends on the selected technological solution. It may include the following elements:
- controllers and hardware and software systems;
- remote control with a touch screen on the front door of the cabinet for setting up the boiler room;
- push-button control post ;
- uninterruptible power supply;
- control devices for drive modes of regulatory mechanisms;
- GSM modem;
- signal working and emergency lamps;
- devices for checking and disabling alarms.
Dispatcher item
The organization of dispatching gas boiler houses is as follows: the mimic diagram is displayed on the dispatcher screen, which graphically shows the structure of technological equipment, pipelines and fittings. The display also shows the main parameters of the coolant.
There are virtual buttons that, when creating an emergency, can change their color. The diagram indicates the place of the accident and its cause. Additionally, SMS messages are sent to those responsible for the safe operation of the boiler room (duty dispatcher, engineer). If necessary, these employees can remotely intervene in the management process and change certain parameters. For various users, a ban on access to part of the information (projects, schemes and their elements) may be imposed.
For the purpose of convenient analysis, technical data can be formed in the form of tables, graphs, daily archives. There are practically no restrictions on the nature and number of operating mode parameters, the number of control centers and the distance between objects for the boiler control system. Its organization can be carried out using a local, remote, global (Internet) network or by a combined scheme.
The SCADA industrial software package and its domestic analogues are used as dispatching tools. The main functions of the control room are:
- data collection and performance evaluation;
- visualization of the received information;
- formation and storage of the archive about the technological process and operator actions;
- differentiation of access rights;
- printing of tables, graphs and other information, its export to other systems.
Benefits
Automation and dispatching of boiler rooms has the following advantages:
- the ability to control processes without the direct involvement of a person;
- cost savings associated with maintenance personnel;
- ensuring the reliability of the technological equipment, increasing the terms of its operation and reducing the cost of repairs;
- timely, automatic liquidation of accidents;
- reduction of energy costs, the possibility of implementing resource-saving programs;
- reduction of the downtime of equipment;
- the possibility of expanding the coverage of facilities;
- quick receipt of a full report on the current state of the boiler room.
Dispatching
For the design and implementation of an automation system, it is necessary to elaborate a set of documentation: circuit diagrams and wiring diagrams, a plan for laying cables, communication lines; working drawings, instructions for automation devices. Such work can be done by the engineering services of the enterprise operating the boiler house, or with the help of third-party organizations that provide professional services in the field of automation.
In the latter case, a contract is drawn up for dispatching the boiler room, which indicates the automation objects, the cost of the work according to the estimate, payment terms, deadlines and responsibility of the parties. After completion of construction and commissioning, the commission of interested parties accepts the control room and the process equipment connected to it. Acceptance tests are carried out according to the approved program and methodology.
The boiler house dispatch estimate includes the following main sections:
- list of installed equipment, automation tools, their price according to the price list and the required quantity;
- types and cost of installation work;
- costs of auxiliary materials;
- overhead;
- estimated profit.