Bale in a gas boiler room on steam boilers. Boiler room control and measuring instruments. Why is automatic control of boiler units introduced?

To regulate and optimize the functioning of boiler units technical means began to be used in initial stages 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 operating personnel.

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 the performance and parameters of the entire complex of devices. Boiler room automation solves the following problems:

Automation object

How the object of regulation is complex dynamic system with many interconnected input and output parameters. Automation of boiler houses is complicated by the fact that the speed of technological processes in steam units is very high. The main adjustable quantities include:

• coolant flow and pressure (water or steam);
• vacuum in the furnace;
• level in the feed reservoir;
• in recent years increased environmental requirements are applied to the quality of the prepared fuel mixture and, as a consequence, to the temperature and composition of smoke removal products.

Automation levels

The degree of automation is set when designing a boiler room or during major repairs/replacement of equipment. It can range from manual control based on the readings of instrumentation to fully automatic control using weather-dependent algorithms. The level of automation is primarily determined by the purpose, power and functional features of equipment operation.

Modern automation of boiler house operation implies an integrated approach - subsystems for monitoring and regulating individual technological processes are combined into a single network with functional group control.

General structure

Boiler room automation is built on 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 for converting, encoding and transmitting information data.

The upper level can be presented in the form of a graphic terminal built into the control cabinet or an automated operator workstation based on a personal computer. All information coming from lower-level microcontrollers and system sensors is displayed here, and operational commands, adjustments and settings are entered. In addition to process dispatching, problems of mode optimization and diagnostics are solved technical condition, analysis of economic indicators, archiving and storage of data. If necessary, information is transferred to the general enterprise management system (MRP/ERP) or locality.

The modern market is widely represented by both individual instruments and devices, and automation kits of domestic and foreign production for steam and hot water boilers. Automation tools include:

• ignition control and flame presence equipment, which starts and controls the fuel combustion process in the combustion chamber of the boiler unit;
• specialized sensors (thrust pressure meters, temperature, pressure sensors, gas analyzers, etc.);
• (solenoid valves, relays, servos, frequency converters);
• control panels for boilers and general boiler equipment (remotes, touch screens);
• switching cabinets, communication lines and power supply.

When choosing management and control, the closest attention should be paid to safety automation, which eliminates the occurrence of abnormal and emergency situations.

Subsystems and functions

Any boiler room includes control, regulation and protection subsystems. Regulation is carried out by maintaining optimal mode combustion by setting the vacuum in the furnace, primary air flow and coolant parameters (temperature, pressure, flow). The control subsystem displays 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, giving a light or sound signal or stopping boiler units with recording of the cause (on a graphic display, mnemonic diagram, panel).

Communication protocols

Microcontroller-based automation minimizes the use of relay switching and control power lines in the functional diagram. To communicate the upper and lower levels of the automated control system, transfer information between sensors and controllers, and broadcast commands to actuators, they use industrial network with a specific interface and data transfer protocol. The most widely used standards are Modbus and Profibus. They are compatible with the bulk of equipment used to automate heat supply facilities. Are different high performance reliability of information transfer, simple and understandable operating principles.

Energy saving and social effects of automation

Automation of boiler houses completely eliminates the possibility of accidents with the destruction of permanent structures and the death of operating personnel. The automated control system is capable of providing 24/7 normal functioning equipment, minimize the influence of the human factor.

In light of the continuous rise in prices for fuel resources, the energy-saving effect of automation is not least important. Saving natural gas, reaching up to 25% during the heating season, is ensured by:

• optimal gas/air ratio in the fuel mixture in all operating modes of the boiler room, correction for the level of oxygen content in combustion products;
• the ability to individually configure not only boilers, but also;
• regulation not only of the temperature and pressure of the coolant at the inlet and outlet of the boilers, but also taking into account environmental parameters (weather-dependent technologies).

In addition, automation allows you to implement an energy-efficient heating algorithm for non-residential premises or buildings not used on weekends and holidays.

Boiler plants are located to reduce costs and increase efficiency. All equipment is divided into main and auxiliary. Boiler installations can be located in one or more rooms in the enterprise.

Main and auxiliary equipment

is a building or separate room, in which liquids or coolants involved in production, heating and product release are heated. The coolant from the boiler room can be supplied to its destinations via heating mains and pipelines.

Boiler equipment comes in three types:

• heating;
• industrial - heating;
• energetic.

The underlying equipment remains almost unchanged. The boiler includes a water economizer, a firebox, an air and steam heater, and a fitting. For ease of maintenance, boiler installations are equipped with stairs and platforms.

Boiler room auxiliary equipment:

• traction equipment;
• controllers;
• pipelines;
• automation systems;
• water treatment devices;
• other equipment to assist in production.

The process of boiler room operation at the enterprise:

• With the help of equipment and with the help of maintenance personnel, fuel is loaded into the furnace.
• The air required for combustion is heated in an air heater to achieve savings in fuel consumption.
• The fuel combustion process provides air flow. Oxygen is supplied naturally through a grate or using a blower fan.
• Combustion products enter a separate cavity, where they cool, and are removed through the chimney using
• Water, having gone through several stages of purification, enters the
• When heated, the water evaporates, accumulates in the drum and enters the steam collector, after which it is distributed to distribution points through pipelines for heating needs.

This is how a steam boiler works and produces steam used in production and heating. Savings are achieved by automating processes; manifolds and controllers are used to supply or shut off liquids and steam.

Process automation

Boiler automation is a complex process, it allows you to reduce human labor costs and increase the level of security at the enterprise. The main work comes down to constant monitoring of the controller. The dispatcher must constantly monitor the indicators and set the necessary parameters for different technological stages production using a controller and remote control.

Read also: Block-modular boiler room

In case of emergency situations or emergency interruption of the supply of one of the production elements (water, oil, electricity) to The remote control sends a signal to the dispatcher indicating a problem has occurred.. The dispatcher is obliged to react in time and turn on a light or sound warning. When automated, the boiler equipment must turn off on its own; To continue work in production, replacement, backup equipment is usually used.

The controller or control unit is the basis of the entire heating automation system. The controller is responsible for all processes and automation operations. The controller can be controlled remotely using a remote control or even a cell phone. Using a “smart” unit, you can keep various logs tracking indicators and then make an analysis of the heating dynamics.

A boiler plant (boiler room) is a structure in which the working fluid (coolant) (usually water) is heated for a heating or steam supply system, located in one technical room. Boiler houses are connected to consumers using heating mains and/or steam pipelines. The main device of a boiler room is a steam, fire tube and/or hot water boiler. Boiler houses are used for centralized heat and steam supply or for local heat supply to buildings.

A boiler plant is a set of devices located in special rooms and used to convert the chemical energy of fuel into the thermal energy of steam or hot water. Its main elements are a boiler, a combustion device (furnace), feeding and draft devices. In general, a boiler installation is a combination of boiler(s) and equipment, including the following devices: fuel supply and combustion; purification, chemical preparation and deaeration of water; heat exchangers for various purposes; source (raw) water pumps, network or circulation - for circulating water in the heating system, make-up - to replace water consumed by the consumer and leaks in networks, feed pumps for supplying water to steam boilers, recirculation (mixing); nutrient tanks, condensation tanks, hot water storage tanks; blower fans and air duct; smoke exhausters, gas path and chimney; ventilation devices; systems automatic regulation and safety of fuel combustion; heat shield or control panel.

A boiler is a heat exchange device in which heat from the hot combustion products of fuel is transferred to water. As a result, water is converted into steam in steam boilers, and heated to the required temperature in hot water boilers.

The combustion device is used to burn fuel and convert its chemical energy into heat of heated gases.

Feeding devices (pumps, injectors) are designed to supply water to the boiler.

The draft device consists of blower fans, a gas-air duct system, smoke exhausters and a chimney, which ensure the supply of the required amount of air to the firebox and the movement of combustion products through the boiler flues, as well as their removal into the atmosphere. Combustion products, moving through flues and coming into contact with the heating surface, transfer heat to water.

To ensure more economical operation, modern boiler systems have auxiliary elements: a water economizer and an air heater, which serve to heat water and air, respectively; devices for fuel supply and ash removal, for cleaning flue gases and feed water; thermal control devices and automation equipment that ensure normal and uninterrupted operation of all parts of the boiler room.

Depending on the use of their heat, boiler houses are divided into energy, heating and industrial and heating.

Energy boiler houses supply steam to steam power plants that generate electricity and are usually part of a power plant complex. Heating and industrial boiler houses are located at industrial enterprises and provide heat for heating and ventilation systems, hot water supply of buildings and technological processes production. Heating boiler houses solve the same problems, but serve residential and public buildings. They are divided into free-standing, interlocking, i.e. adjacent to other buildings, and built into buildings. IN lately Increasingly, free-standing enlarged boiler houses are being built with the expectation of servicing a group of buildings, a residential area, or a microdistrict.

The installation of boiler rooms built into residential and public buildings is currently permitted only with appropriate justification and agreement with the sanitary inspection authorities.

Boiler rooms low power(individual and small group) usually consist of boilers, circulation and make-up pumps and draft devices. Depending on this equipment, the dimensions of the boiler room are mainly determined.

2. Classification of boiler installations

Boiler installations, depending on the nature of consumers, are divided into energy, production and heating and heating. Based on the type of coolant produced, they are divided into steam (for generating steam) and hot water (for producing hot water).

Power boiler plants produce steam for steam turbines in thermal power plants. Such boiler houses are usually equipped with high- and medium-power boiler units that produce steam with increased parameters.

Industrial heating boiler systems (usually steam) produce steam not only for industrial needs, but also for heating, ventilation and hot water supply.

Heating boiler systems (mainly hot water, but they can also be steam) are designed to service heating systems for industrial and residential premises.

Depending on the scale of heat supply, heating boiler houses are local (individual), group and district.

Local boiler houses are usually equipped with hot water boilers that heat water to a temperature of no more than 115 °C or steam boilers with an operating pressure of up to 70 kPa. Such boiler houses are designed to supply heat to one or more buildings.

Group boiler systems provide heat to groups of buildings, residential areas or small neighborhoods. They are equipped with both steam and hot water boilers with higher heating capacity than boilers for local boiler houses. These boiler rooms are usually located in specially constructed separate buildings.

District heating boiler houses are used to supply heat to large residential areas: they are equipped with relatively powerful hot water or steam boilers.

Rice. 1.

Rice. 2.

Rice. 3.

Rice. 4.

It is customary to conventionally show individual elements of a boiler installation schematic diagram in the form of rectangles, circles, etc. and connect them to each other with lines (solid, dotted), indicating a pipeline, steam lines, etc. There are significant differences in the basic diagrams of steam and water heating boiler plants. A steam boiler plant (Fig. 4, a) consisting of two steam boilers 1, equipped with individual water 4 and air 5 economizers, includes a group ash collector 11, to which the flue gases are approached through a collection hog 12. For suction of flue gases in the area between the ash collector 11 and smoke exhausters 7 with electric motors 8 are installed in the chimney 9. To operate the boiler room without smoke exhausters, dampers 10 are installed.

Steam from the boilers through separate steam lines 19 enters the common steam line 18 and through it to the consumer 17. Having given up heat, the steam condenses and returns through the condensate line 16 to the boiler room in the collecting condensation tank 14. Through pipeline 15, additional water from the water supply or chemical water treatment is supplied to the condensation tank (to compensate for the volume not returned from consumers).

In the case when part of the condensate is lost from the consumer, a mixture of condensate and additional water is supplied from the condensation tank by pumps 13 through the supply pipeline 2, first into the economizer 4, and then into the boiler 1. The air required for combustion is sucked in by centrifugal blower fans 6 partially from the room boiler room, partly from the outside and through air ducts 3, it is supplied first to air heaters 5, and then to the boiler furnaces.

The water heating boiler installation (Fig. 4, b) consists of two water heating boilers 1, one group water economizer 5, serving both boilers. Flue gases leaving the economizer through a common collection duct 3 enter directly into the chimney 4. Water heated in the boilers enters the common pipeline 8, from where it is supplied to the consumer 7. Having given off heat, the cooled water through the return pipeline 2 is sent first to the economizer 5 , and then again into the boilers. Water is moved through a closed circuit (boiler, consumer, economizer, boiler) by circulation pumps 6.

Rice. 5. : 1 - circulation pump; 2 - firebox; 3 - steam superheater; 4 - upper drum; 5 - water heater; 6 - air heater; 7 - chimney; 8 - centrifugal fan(smoke exhauster); 9 - fan for supplying air to the air heater

In Fig. Figure 6 shows a diagram of a boiler unit with a steam boiler having an upper drum 12. At the bottom of the boiler there is a firebox 3. To burn liquid or gaseous fuel, nozzles or burners 4 are used, through which the fuel together with air is supplied to the firebox. The boiler is limited by brick walls - lining 7.

When burning fuel, the heat released heats water to a boil in tube screens 2 installed on the inner surface of the firebox 3 and ensures its transformation into water vapor.

Fig 6.

Flue gases from the furnace enter the boiler flues, formed by lining and special partitions installed in the pipe bundles. When moving, the gases wash the bundles of pipes of the boiler and superheater 11, pass through the economizer 5 and the air heater 6, where they are also cooled due to the transfer of heat to the water entering the boiler and the air supplied to the firebox. Then, the significantly cooled flue gases are removed through the chimney 19 into the atmosphere using a smoke exhauster 17. Flue gases can be removed from the boiler without a smoke exhauster under the influence of natural draft created by the chimney.

Water from the water supply source is supplied through the supply pipeline by pump 16 to the water economizer 5, from where, after heating, it enters the upper drum of the boiler 12. Filling of the boiler drum with water is controlled by a water indicator glass installed on the drum. In this case, the water evaporates, and the resulting steam is collected in the upper part of the upper drum 12. Then the steam enters the superheater 11, where due to the heat of the flue gases it is completely dried and its temperature rises.

From the superheater 11, steam enters the main steam line 13 and from there to the consumer, and after use it is condensed and returned to the boiler room in the form of hot water (condensate).

Losses of condensate from the consumer are replenished with water from the water supply or from other water supply sources. Before entering the boiler, water is subjected to appropriate treatment.

The air required for fuel combustion is taken, as a rule, from the top of the boiler room and supplied by fan 18 to air heater 6, where it is heated and then sent to the furnace. In boiler houses of small capacity, there are usually no air heaters, and cold air is supplied to the firebox either by a fan or due to the vacuum in the firebox created by the chimney. Boiler installations are equipped with water treatment devices (not shown in the diagram), control and measuring instruments and appropriate automation equipment, which ensures their uninterrupted and reliable operation.

Rice. 7.

For proper installation of all elements of the boiler room, use a wiring diagram, an example of which is shown in Fig. 9.

Rice. 9.

Hot water boiler systems are designed to produce hot water used for heating, hot water supply and other purposes.

To ensure normal operation, boiler rooms with hot water boilers are equipped with the necessary fittings, instrumentation and automation equipment.

A hot water boiler house has one coolant - water, in contrast to a steam boiler house, which has two coolants - water and steam. In this regard, the steam boiler room must have separate pipelines for steam and water, as well as tanks for collecting condensate. However, this does not mean that the circuits of hot water boiler houses are simpler than steam ones. Water heating and steam boiler houses vary in complexity depending on the type of fuel used, the design of the boilers, furnaces, etc. Both steam and water heating boiler systems usually include several boiler units, but not less than two and no more than four or five . All of them are connected by common communications - pipelines, gas pipelines, etc.

The design of lower power boilers is shown below in paragraph 4 of this topic. To better understand the structure and principles of operation of boilers different power, it is advisable to compare the design of these less powerful boilers with the design of the higher-power boilers described above, and find in them the main elements that perform the same functions, as well as understand the main reasons for the differences in designs.

3. Classification of boiler units

Boilers as technical devices for the production of steam or hot water are distinguished by a variety of design forms, principles of operation, types of fuel used and production indicators. But according to the method of organizing the movement of water and steam-water mixture, all boilers can be divided into the following two groups:

Boilers with natural circulation;

Boilers with forced movement of coolant (water, steam-water mixture).

In modern heating and heating-industrial boiler houses, boilers with natural circulation are mainly used to produce steam, and boilers with forced movement of coolant operating on the direct-flow principle are used to produce hot water.

Modern steam boilers with natural circulation are made from vertical pipes located between two collectors (upper and lower drums). Their device is shown in the drawing in Fig. 10, photograph of the upper and lower drum with the pipes connecting them - in Fig. 11, and placement in the boiler room is shown in Fig. 12. One part of the pipes, called heated “riser pipes,” is heated by the torch and combustion products, and the other, usually unheated part of the pipes, is located outside the boiler unit and is called “descent pipes.” In heated lifting pipes, water is heated to a boil, partially evaporates and enters the boiler drum in the form of a steam-water mixture, where it is separated into steam and water. Through lowering unheated pipes, water from the upper drum enters the lower collector (drum).

The movement of the coolant in boilers with natural circulation is carried out due to the driving pressure created by the difference in the weights of the water column in the lowering pipes and the column of steam-water mixture in the rising pipes.

Rice. 10.

Rice. 11.

Rice. 12.

In steam boilers with multiple forced circulation heating surfaces are made in the form of coils that form circulation circuits. The movement of water and steam-water mixture in such circuits is carried out using a circulation pump.

In direct-flow steam boilers, the circulation ratio is unity, i.e. feed water, heating up, it successively turns into a steam-water mixture, saturated and superheated steam.

In hot water boilers, water moving along the circulation circuit is heated in one revolution from the initial to the final temperature.

Based on the type of coolant, boilers are divided into hot water and steam boilers. The main indicators of a hot water boiler are thermal power, that is, heating capacity, and water temperature; The main indicators of a steam boiler are steam output, pressure and temperature.

Hot water boilers, the purpose of which is to obtain hot water of specified parameters, are used to supply heat to heating and ventilation systems, household and technological consumers. Hot water boilers, usually operating on the direct-flow principle with constant flow water are installed not only at thermal power plants, but also in district heating, as well as heating and industrial boiler houses as the main source of heat supply.

Rice. 13.

Rice. 14.

By relative motion heat exchange media (flue gases, water and steam), steam boilers (steam generators) can be divided into two groups: water-tube boilers and fire-tube boilers. In water-tube steam generators, water and a steam-water mixture move inside the pipes, and flue gases wash the outside of the pipes. In Russia in the 20th century, Shukhov water-tube boilers were mainly used. In fire tubes, on the contrary, flue gases move inside the pipes, and water washes the pipes outside.

Based on the principle of movement of water and steam-water mixture, steam generators are divided into units with natural circulation and with forced circulation. The latter are divided into direct-flow and multiple-forced circulation.

Examples of placement of boilers of different capacities and purposes, as well as other equipment, in boiler rooms are shown in Fig. 14-16.

Rice. 15.

Rice. 16. Examples of placement of domestic boilers and other equipment

Methodology and procedure for checking security automation.

Safety automation checks are carried out by certified specialists with extensive experience who have been trained by equipment manufacturers. Specialists are equipped modern equipment and devices. When checking the safety automation, the operation of the tested parameter is checked and its compliance with the safety automation settings map. Tuning maps are drawn up during operational testing and commissioning of instrumentation and control equipment.

When checking safety automation, service technicians use the instructions developed during operational testing. An example of checking the automation of a Vitoplex 100 boiler with a Weishaupt burner

1. Checking the parameter “Maximum gas pressure in front of the valves”.

On the gas pressure sensor, gradually lower the parameter setting, bringing it to the operating value. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

2. Checking the parameter “Minimum gas pressure in front of the valves”.

Slowly closing gas tap in front of the burner, reduce the gas pressure according to the indicating device in front of the valves to the value specified in the Safety Automation Settings Card. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

3. Checking the parameter “Minimum fan air pressure”.

At the very beginning of pre-purge, turn off the burner fan power supply. Monitor the air pressure drop using a TESTO micromanometer, when the air pressure drop drops to that specified in the Parameter Card. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

4. Checking the “Burner flame extinction” parameter.

Check the flame extinction by simulation. On the boiler control panel, press the “check flame sensor” button. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

5. Checking the parameter “Increasing the water temperature behind the boiler”.

Lower the temperature setpoint on the emergency thermostat. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

6. Checking the parameter “Vacuum in the gas duct behind the boiler”.

Slowly closing the valve on the flue of the boiler's exhaust gases will trigger the safety automatics, controlling the vacuum value with an external device.

7. Checking the parameter “Reducing water pressure behind the boiler”.

Reduce the water pressure at the boiler outlet to the value specified in the Parameter Map. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

8. Checking the parameter “Increasing water pressure behind the boiler”.

Increase the water pressure at the boiler outlet to the value specified in the Parameter Card. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

9. Checking the “Power outage” parameter.

To carry out this test, it is enough to turn off the circuit breaker (circuit breaker) located in the power cabinet. The burner will turn off and a light and sound signal will be issued on the control panel. Bring the systems and mechanisms of the boiler installation to their original condition.

Security automation service agreement.

Before concluding a contract for servicing the automation, a specialist from Energia LLC visits the site to conduct a technical inspection of the boiler room equipment. Based on the results of the inspection, all information about the boiler room with identified comments and defects is entered into the report. In this field, a commercial offer is submitted to maintenance Instrumentation and automation, as well as proposals for eliminating equipment defects. If the customer has unresolved Rostechnadzor regulations, ways to solve the problem are proposed.