General structure
Automation of boiler houses is built according to a two-level control scheme. The lower (field) level includes local automation devices based on programmable microcontrollers that implement technical protection and blocking, adjustment and change of parameters, primary converters of physical quantities. This also includes equipment designed to convert, encode and transmit information data.
The upper level can be presented in the form of a graphical terminal built into the control cabinet or an operator's workstation based on a personal computer. It displays all the information coming from the lower-level microcontrollers and sensors of the system, and enters operational commands, adjustments and settings. In addition to process dispatching, the tasks of optimizing modes, diagnosing the technical condition, analyzing economic indicators, archiving and storing data are solved. If necessary, the information is transferred to the general management system of the enterprise (MRP / ERP) or the locality.
Boiler safety and regulation automation
ABU-1 automation kit for a training fire-tube boiler of the “Turboterm” type
Pump control cabinet
Touch panel for indication of operating parameters of a fire-tube boiler of the “Turboterm” type
Frequency control cabinet for network pumps in the boiler room
Control panel and emergency interlocks for a fire-tube boiler of the “Turboterm” type
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TOR ON THE THEME "AUTOMATIC SAFETY OF BOILERS AND REGULATION"
Test "Automatic boiler safety and regulation" to test the knowledge of the operators of the gas boiler. The main element of the boiler safety automation circuit is the gas cut-off valve. Urgently check your professional competence and demand in the labor market!
KNOWLEDGE ASSESSMENT TEST QUESTIONS
1. Choose the correct answer from those offered. The gas cut-off valve in the automatic safety circuit of a hot water boiler is used for:
a) regulation of the pressure of the gas entering the boiler;
b) regulation of the flow of gas entering the boiler;
c) automatic shutdown of gas supply to the boiler when any parameter involved in the boiler safety automatics circuit is exceeded.
2. Choose the correct answer from those offered. The delay in the operation of the gas shut-off valve in the safety automation circuit for reducing the air pressure in front of the burner:
a) is allowed and this should be reflected in the Production Instructions; b) is not allowed.
3. Choose the correct answer from those offered. Common sensors in safety and control automation circuits are as follows:
a) only a sensor for water temperature after the boiler; b) water temperature sensor after the boiler and gas and air pressure sensors before the burner; c) there are no common sensors for safety automation circuits and boiler control automation.
4. Choose the correct answer from those offered. Technical pressure gauge measures pressure:
a) atmospheric; b) excess; c) absolute; d) vacuum gauge.
5. Choose the correct answer from those offered. Checking the serviceability of the pressure gauge is carried out:
a) each shift, by setting the pressure gauge to zero, by the boiler room operator; b) once every six months by the instrumentation and automation service; c) once a year by the Lord.
Liquid manometers
6. Choose the correct answer from those offered. The accuracy of measuring pressure with a liquid manometer is higher than y: ( P is the measured pressure; h is the difference in liquid levels; h1- change in the liquid level in the tube; h2 change in the level of the liquid in the vessel).
a) U-shaped manometer; b) cup; c) micromanometer.
7. Choose the correct answer from those offered. The delay in the operation of the gas shut-off valve in the safety automation circuit for extinguishing the burner torch:
a) is allowed and this should be reflected in the Production Instructions; b) is not allowed.
8. Choose the correct answer from those offered. Operation of a hot water gas boiler with a faulty automatic control system:
a) not allowed; b) is allowed.
9. Choose the correct answer from the options provided. With this position of the three-way valve of the pressure gauge, the following is performed:
Boiler pressure gauge with three-way cock
a) blowing out the siphon tube; b) checking the working pressure gauge against the control pressure gauge; c) measurement of working pressure; d) checking the pressure gauge by setting it to zero; e) accumulation of condensate in the siphon tube (if steam parameters are measured).
QUESTIONS FOR THE ASSESSMENT OF SKILLS AND SKILLS
10. Complete. Automatic regulation of hot water boilers includes:
Dear friend! The answers to this test can be found in the Boiler Operator Test Kit or in the Boiler Operator Training Manual. These information materials are paid. It is advisable to have them in your personal library. Questions and recommendations can be left on the Contacts page of the site. See you!
Tasks and goals
Modern boiler room automation systems are able to guarantee trouble-free and efficient operation of equipment without direct operator intervention. Human functions are reduced to online monitoring of performance and parameters of the entire complex of devices. Automation of boiler houses solves the following tasks:
- Automatic start and stop of boiler units.
- Boiler power regulation (cascade control) according to the given primary settings.
- Management of feed pumps, control of coolant levels in the working and consumer circuits.
- Emergency stop and activation of signaling devices, in case the system operating values go beyond the established limits.
Subsystems and functions
Any boiler house automation scheme includes subsystems for control, regulation and protection. Regulation is carried out by maintaining the optimal combustion mode by setting the vacuum in the furnace, the primary air flow rate and the coolant parameters (temperature, pressure, flow rate). The control subsystem outputs the actual data on the operation of the equipment to the human-machine interface. Protection devices guarantee the prevention of emergency situations in case of violation of normal operating conditions, the supply of a light, sound signal or the shutdown of boiler units with fixation of the cause (on a graphic display, mnemonic diagram, shield).
Automated block-modular gas boiler house
Project Options
Thermal power of the designed boiler house is 5.7 MW. The heating system is single-circuit, closed. The main fuel is natural gas, the reserve is diesel fuel. Installed volume of natural gas consumption: 2.955 million m3/year, 0.759 thousand m3/hour.
Project description
Feasibility study: Block-modular gas boiler house, taking into account the change of liquid fuel (fuel oil) to cheaper gaseous fuel (natural gas) with the lowest maintenance costs of the new boiler house. Project scope: 1. Hot water boilers with a total heat output of 5 MW. The use of 3 imported automated fire-tube hot water boilers with a water heating temperature of not more than 338 K (1150 C) and an efficiency of more than 90%, with the ability to work offline.
2. Gas burners.The use of 3 imported automated combined (gas-diesel) burners that ensure safe operation, excluding human intervention, with the minimum allowable emissions of pollutants into the environment.
3. The automatic safety system of the boiler unit in accordance with the requirements of the "Rules for the Design and Safe Operation of Steam Boilers with Steam Pressure Not More Than 0.07 MPa (0.7 kgf/cm2) Hot Water Boilers and Water Heaters with Water Heating Temperature Not Above 338 K (1150 C) )
4. Pumping equipment of the boiler room with an automatic backup system. The use of imported pumping units with reduced energy consumption and automatic protection of the main operating parameters.
5. System of automatic control of power of the boiler room. The use of weather-dependent automatic control of the power of the boiler room, which has the ability to operate the boiler room according to one of the four standard temperature schedules for heat supply.
6. System of make-up and pre-boiler water treatment. The use of imported automated chemical water treatment systems operating on the principle of Na-cationization. The use of imported automated systems for the chemical purification of water from iron compounds is determined by the results of the source water. The use of imported automated systems for complex dosing of the reagent to adjust the quality of the coolant.
7. Heat carrier consumption metering system - the use of commercial gas metering units with telemetry of cold water, thermal energy and hot water consumption.
8. Gas supply system of the boiler house - the use of block gas control points in accordance with the "Safety Rules for Gas Distribution and Gas Consumption Systems" is determined on the basis of the boiler house reconstruction project.
9. Power supply system of the boiler house - the use of cabinet input switchgears of power equipment is determined on the basis of the boiler house reconstruction project.
Automation systems Set of controls Mode Set of controls - version Mode-1-01
Execution "Mode-1-01" is designed to automate the operation of gas burners with 2-stage and smooth control equipped with an ignition burner with a power of not more than 70 kW, installed on hot water boilers with a power of 0.3 to 3.15 MW and a water heating temperature of not over 115°C.
To order a set of KSU "Mode-1" instead of an existing unit, only the serial number and year of manufacture are required. If the control unit is “older” than 2002, it is necessary to provide information about the type of burner and the brand of the boiler. The block in terms of connecting characteristics (connectors) is completely identical to the previously produced blocks.
Main characteristics:
- Automatic regulation of water temperature pressure at the outlet of the boiler, two-position or pulse regulation law.
- Boiler negative pressure stabilization, two-position or pulse regulation law.
Boiler start blocking:
- - in the event of a power outage;
- - with a lack of air for combustion;
- - at a gas pressure downstream of the main shut-off valve 30% lower or higher than the nominal value;
- - in case of violation of tightness of the burner valves;
- - in case of malfunctions of the purge and removal of combustion products (switching off the smoke exhauster, fan);
- - in the absence of the necessary vacuum;
- - with an increase or decrease in water flow in the boiler above or below the permissible value;
- - when the temperature rises at the outlet of the boiler.
- Blocking the gas supply to the main burner in the absence of a pilot burner flame.
- Protective shutdown of the boiler burner, if the fuel does not ignite during its ignition within a time period of not more than 3 s
Protective shutdown of the boiler burner in working condition in the following cases:
- - when the controlled flame goes out; - in the event of a power outage;
- - when the gas pressure downstream of the main shut-off valve is more than 30% lower or higher than the nominal value;
- - with a lack of air for combustion;
- - in case of malfunctions of the purge and removal of combustion products (switching off the smoke exhauster, fan);
- - in the absence of the necessary vacuum;
- - when the temperature rises at the outlet of the boiler;
- - when the water flow through the boiler rises or falls above or below the allowable value.
The device of burners for the execution "Mode-1-01"
1- First valve
2- Normally open safety valve
3- Second valve
4- Pilot valve
5- Gas and air damper drive
6- Air fan
7- Air damper
8- Ignition transformer
9- Gas damper
Note: The fan of the smoke exhauster is conditionally not shown
Scheme of external connections of KSU Mode-1-01 (click to view in full size)
01.12.2019
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Automation object
Boiler equipment as an object of regulation is a complex dynamic system with many interrelated input and output parameters. The automation of boiler houses is complicated by the fact that the speed of technological processes in steam units is very high. The main adjustable values include:
- flow rate and pressure of the coolant (water or steam);
- vacuum in the furnace;
- level in the nutrient tank;
- In recent years, increased environmental requirements have been imposed on the quality of the prepared fuel mixture and, as a result, on the temperature and composition of smoke exhaust products.
Automation of boiler equipment
The modern market is widely represented by both individual instruments and devices, and domestic and foreign-made automation kits for steam and hot water boilers. Automation tools include:
- ignition control equipment and the presence of a flame, which starts and controls the process of fuel combustion in the combustion chamber of the boiler unit;
- specialized sensors (draft and pressure gauges, temperature and pressure sensors, gas analyzers, etc.);
- actuators (solenoid valves, relays, servo drives, frequency converters);
- control panels for boilers and general boiler equipment (panels, touch screens);
- switching cabinets, communication lines and power supply.
When choosing technical means of control and monitoring, the closest attention should be paid to safety automation, which excludes the occurrence of emergency and emergency situations.
Automated boiler room
Automated boiler rooms must operate continuously without personnel on duty with a smooth change in the gas supply to the boiler burners, which is signaled by the burning of its light bulb on the shield.
Closely located automated boiler houses are combined into clusters of 5-20 boiler houses. Each bush is serviced by a dispatcher station located in one of the boiler houses of this bush or in a separate room. The alarm system of automation is electrical. A fault signal is sent by wire to the control panel located in the control room.
Each automated boiler room must be provided with telephone communication with the cluster control room, for which a channel can be used through which emergency information is automatically transmitted.
In automated boiler houses, the heating system is replenished with water manually. At the same time, the operation of the boiler room is additionally controlled. If the system is not replenished with water for a long time, then the automation turns off the boilers when the level drops below the permissible level.
The start-up of an automated boiler house must begin with checking the documentation for the work performed, including hidden ones, and adjusting gas combustion using proportional air valves with the main valve turned off.
Maintenance of automated boiler houses is carried out by the duty personnel of the control room, who is responsible for all the equipment of the boiler room and the efficiency of its operation.
In fully automated boiler rooms, operating without permanent maintenance personnel, a malfunction signal is sent to the control room.
The practice of operating automated boiler houses controlled from a central control center has shown that its personnel must perfectly know the systems of automatic devices of boiler houses controlled by this point, the rules for stopping and igniting automated boilers.
Prior to the commissioning of an automated boiler house, the organization - the owner of the boiler house - must submit a certificate of compliance with all the requirements for boiler rooms specified in Ch.
In the conditions of dispatching maintenance of automated boiler houses, the block principle of constructing an automation scheme has certain advantages. In case of failure of any of the blocks, it can be quickly and easily replaced with a serviceable one.
To ensure the trouble-free operation of automated boilers, their preventive maintenance is necessary. Preventive maintenance work is carried out in accordance with the instructions and schedules that regulate the nature, volume and frequency of work performed. Operating instructions for automated boiler houses should be drawn up in such a way that, through properly organized prevention, the possibility of accidents is practically excluded.
The main purpose of a preventive inspection of an automated boiler house is to identify and eliminate implicit failures in safety automation.
On the gas pipeline supplying the automated boiler room, a gas filter from mechanical impurities must be installed.
To regulate and optimize the functioning of boiler units, technical means began to be used even at the initial stages of automation of industry and production. The current level of development in this area can significantly increase the profitability and reliability of boiler equipment, ensure the safety and intellectualization of the work of maintenance personnel.
Communication protocols
Automation of boiler installations based on microcontrollers minimizes the use of relay switching and control power lines in the functional circuit. To connect the upper and lower levels of the automated control system, transfer information between sensors and controllers, to translate commands to actuators, an industrial network with a specific interface and data transfer protocol is used. The most widespread standards are Modbus and Profibus. They are compatible with the bulk of the equipment used to automate heating facilities. They are distinguished by high rates of reliability of information transfer, simple and understandable principles of functioning.
