Boiler utilizer principle of operation is simple and efficient

Few things are more important for keeping our homes warm and comfortable than a dependable boiler system. Boilers are an essential part of our daily lives, whether they are used for water heating or to maintain a comfortable temperature inside. But after it’s used, have you ever wondered what happens to all that heat? Boiler utilizers provide a straightforward yet incredibly effective way to maximize that residual heat in this situation.

The principle by which boiler utilizers work is both clever and useful. In essence, they take the extra heat that a boiler system produces and use it for different household chores. With a boiler utilizer, this precious energy is not wasted but is instead used to heat water for showers, warm air for ventilation systems, or even warm floors in the winter.

Heat exchange is the fundamental function of the boiler utilizer. Naturally, some of the heat produced by the hot water that circulates through the boiler system to provide warmth is lost. This excess heat is directed through a network of pipes or coils by the user instead of vanishing into the surroundings. By effectively distributing heat to the areas that require it most, these parts maximize energy efficiency and lower utility costs.

The simplicity of boiler utilizers is one of their main benefits. Boiler utilizers are simple to design and operate, in contrast to certain other energy-saving technologies that are more complicated. Their simplicity guarantees dependable performance over time and makes them simpler to install and maintain. Utilizers provide homeowners with a hassle-free way to increase energy efficiency without requiring significant renovations or disruptions because they integrate seamlessly with existing boiler systems.

Simple Principle Efficient Operation
The boiler utilizes fuel or electricity to heat water. It effectively transfers heat to water for heating purposes.

Multifunctional protection

The boiler’s safety feature guarantees dependable, long-term operation under various conditions, including emergency scenarios.

Designs that have up to seven levels of protection are the safest ones.

  1. Cooling heat exchanger with emergency thermostat against unit overheating.
  2. Equipped with special systems to protect the pumps against jamming.
  3. System with electric heating element that prevents the boiler from freezing.
  4. Safety valve that protects against overpressure.
  5. System protection against boiling when the power supply is cut off.
  6. Smoke extraction system.
  7. Control of CO in the gases at the chimney outlet.

The boiler can be operated without a person being present and with constant control over its operation because of this range of protection.

Purpose and application area

The term "heat recovery boiler" (HRSG) refers to a steam or hot-water boiler that uses the heat from waste gases from technological industrial units for a variety of applications instead of having a separate furnace for burning fuel. The heat produced by the HRSG is used in cogeneration plants to generate electricity or in other technological processes as heated water vapor, heated air flow, or both.

Boilers that operate on waste gases that contain both physical and chemical heat in the form of combustible components that are best burned off are an exception. In oil refineries, where carbon monoxide is produced during production processes, such equipment is actively used. This gas powers turbines as it burns in the boiler furnace, contributing to the production process. Emissions into the atmosphere become negligible in this scenario.

Waste heat recovery boiler application areas are categorized based on the following attributes:

  • industries, which use secondary energy resources: boilers for thermal power plants, ferrous and non-ferrous metallurgy, chemical industry; sulfuric acid and nitrogen production, pulp and paper, construction, oil refining and petrochemical industry;
  • technological units, behind which or in which heat-using boilers are installed: behind gas turbines, open-hearth furnaces, converters, fluidized bed roasting, fuming, heating, slag-burning, calcining, shaft, reflection furnaces, oxygen-weighted smelting furnaces, dry coke quenching furnaces, etc., etc.;

Steam recovery boilers at TPPs are made to use exhaust gases to produce superheated steam and the potential for additional use, which increases the efficiency of the gas turbine power plant cycle. The superheated steam that is produced is used to meet technological demands, produce electricity, and enhance the power plant’s environmental characteristics by lowering noise levels and exhaust gas temperatures.

HRSGs are utilized in many different industries; metallurgical and petrochemical plants, among others, are among those where they are installed. This boiler equipment can be a part of cogeneration plants, which are best suited for businesses with high steam and hot water needs in terms of payback.

Recovering boiler equipment

Even though the basic design of such equipment includes a wide range of auxiliary devices, as the plant grows or is relocated, different additions might be needed. Specifically, the protection systems consist of shut-off valves, safety blocks, mounted elements, and heat-resistant shields. Sanitary fittings are used for the device of complex circulation systems, enabling the design of various device heat exchangers. The HRSG is additionally equipped with air injection fans and pumping machinery to maintain adequate pressure.

Design and operation of the HRSG

Boiler condensatequality requirements for condensate

HRSG with a horizontal profile, drum, three pressure settings (high, medium, and low), industry superheating, and natural circulation in evaporator circuits. At the boiler outlet, a gas condensate heater is installed.

Through intermediary metal structures, the HRSG is suspended from its own frame. When the CHP frame is assembled, high-strength bolted joints are used to join the various steel structure components.

Feed water quality requirements

The boiler heating surfaces are organized into five modules that are positioned successively along the gas flow. Each module is made up of five blocks wide. Units themselves are made up of discrete heat exchange tube sections.

Each boiler has its own separate chimney from which GTU exhaust gases are released into the atmosphere.

An independent boiler is used to perform condensate deaeration for the HRSG.

When the outside air temperature drops from plus 34° to minus 51°¡, the CHP permits operation at a change in the flow rate and temperature of gases coming from GTU.

Operating range of CHP load variation in compliance with the designated GTU load variation operating range, including pumping equipment. Changing the GTU’s fuel and air flow rates allows for load changes. At the CHP inlet, there are modifications to the temperature and flow rate of gases.

The sliding steam parameters used by CHP are based on the steam turbine’s specifications as well as the temperature and flow rate of the gases exiting the GTU. The steam cooler uses feed water injection to provide high-pressure steam temperature control.

The boiler is a gas duct that runs horizontally and contains sections of heating surfaces. The GTU’s utilization gases flow through the CHP’s inlet gas duct, where they sequentially clean all of the heating surfaces, and then exit the gas duct into the chimney.

By installing a cut-off valve at the CHP unit outlet at the chimney inlet, the boiler can be kept in hot reserve thanks to the design of the CHP unit.

Characteristics of utilizer boilers

The necessity to burn gases with a fuel structure component, particularly for internal combustion and diesel engines, explains the viability of such boilers.

Utilizer boilers generate and store energy in the form of intensely heated water, steam streams, or air convection. These characteristics underpin their operation.

This energy can be freely used to generate mechanical work or other forms of energy.

The utilization of heat energy from fuel combustion can be greatly expanded with the help of a boiler utilizer device, which lowers the temperature of the unit heating element, increases the efficiency of the fuel and the installation, and enables the capture of exhausts and hazardous gases.

Three variables affect the utilizer’s efficiency: the volume, temperature, and supply method of the gas that enters the boiler.

The type of production directly affects the gas’s temperature and volume. The industry producing the most waste gases is oil refining, according to statistics. The steel industry also contributes significantly to gas emissions.

Charge gas, a medium containing metal scale that facilitates gas ignition and combustion, is produced by this industry.

As the fundamental component of the heating system, the boiler’s power is equivalent to the network’s total heat loss, giving a room specific measurements and thermal characteristics.

Read on to learn more about pellet boilers.

An equally important factor is the mode that explains how the gas gets into the boiler. The majority of technical installations have cyclical supply, which has little effect on how the utilizer boiler is "fed."

Since the boiler in this instance only uses very small amounts of gas, using them further is not justified.

This is frequently seen in argon welding inverter shops, which use a closed cycle with little waste.

Water-tube utilizer

In the industry, users with multiple forced circulation are commonly employed. The forced circulation feature of this type of analyzer permits the evaporator element to take on any shape and orientation in space.

Because the evaporator system in these boilers is divided into multiple sections and connected in parallel, you can use circulation pumps with lower capacities and greatly reduce the resistance of the evaporator part.

The water that feeds the utilizer flows through the water economizer and then into the boiler drum. From here, by means of a pump, the water goes through the sludge separator to the evaporator packages, which are connected in parallel. The resulting steam-water mixture is separated in the drum and the water is separated from the steam. After that the steam goes through the superheater to the consumer. Depending on where the utilizer is to be installed, its layout can be U-shaped, tower or horizontal.
HRSGs in combined cycle and cogeneration plants
In combined cycle plants, HRSGs are used, which are designed to produce medium and high pressure steam for further use in a steam turbine. In such a boiler the energy source is also the energy of the waste gases. Water tube boilers are used here, which have convective heating surfaces and multiple forced circulation. The boiler design will depend on the steam turbine capacity, it can be single-circuit or have 2 independent circuits with different steam pressures.

These drum utilizers use the heat from the gas turbine plant’s exhaust gases to produce hot water and steam at pressures ranging from 0.65 to 8 MPa.

Utilizer boilers are boilers in cogeneration plants that use the exhaust heat from gas turbines or reciprocating engines. Produce steam for use in technology or to heat water for the heating system. These boilers have forced circulation and are constructed single-circuit.

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The principle of operation of the hot water heating unit

The heat supply of buildings and other structures is an expression of how the water heating unit’s work is put to use. To keep the water from boiling over and turning to steam, the heat transfer medium in the unit is heated to a temperature above 100 degrees. High pressure is also maintained within the device. Boiling and scale formation are examples of less destructive processes that happen during operation the higher this characteristic is.

Water enters the coil in the area exposed to flammable gases created by fuel combustion with the use of a pump. After being heated, the water enters the system, completes the loop, and returns to the HRSG. When the device has two circuits, it not only heats but also produces hot water. In order to improve the water heating unit’s efficiency, a steam collector may occasionally be connected to it using unique branches that emerge from the top.

The parameters of fuel burned and the temperature of combustible gases at the outlet are used to calculate waste heat recovery boilers. During testing, the appliance’s manufacturer determines how to describe these values. The waste heat boiler’s thermal calculation aids in selecting the unit’s ideal form and design as well as the required surface area that provides the heat carrier with useful energy. The more efficiently the HRSGs operate, the smaller the temperature differential between combustible gases and water.


View 1 of HRSG over GTU

HRSG uses GTU flue gases, which is why it is intended for steam generation.

The boiler’s common gas duct should house the steam superheater, evaporator, economizer, and network heater in the order listed along the gas flow. Gas-tight, naturally circulating boiler built to withstand pressure.

The boiler ought to be engineered to function within the subsequent nominal parameters:

– steam capacity 40 t/h;
– steam pressure behind the boiler (abs.) 3.9 MPa;
– superheated steam temperature 440 °С;
– feed water temperature – feed water pressure 104 °С; 5.4…5.0 MPa;
– inlet gas temperature (nominal) 104 °С;
– inlet gas temperature (maximum design temperature) 600 °С;
– flue gas temperature, not more than 100 °С;
– gas path resistance 2200 Pa.

Network water heater using gas and water:

– 70 °¡ at the water inlet;

– 150 °Ρ for the outlet water temperature;

1.6 MPa of water pressure at the inlet;

– 7,5 Gcal/h of heat capacity (name the CHP manufacturer).

It is necessary to ascertain the primary design features of the HRSG for the gas turbine unit’s typical operating conditions.

– temperature of the outside air: +15 °C;

– 0.1013 MPa of air pressure at the GTU inlet;

60% of the air is humid at the GTU inlet.

With no further natural gas combustion in the oxidizing hot gas environment following the gas turbine engine, the boiler operates in the utilization mode.

The GTU’s operating capacity determines the HRSG’s steam capacity, while maintaining a constant steam pressure.

Requirements to utilization modes

When the outside air temperature drops from plus 35 to minus 40 °C, the HRSG must ensure that the boiler operates at the appropriate flow rate and temperature.

The relevant calculation tables and correction graphs should be included in the technical documentation in order to assess the HRSG’s performance at various outdoor air temperatures and gas turbine loads.

Throughout the whole operating range of GTU loads (50–100% of nominal capacity), HRSG should offer automatic maintenance of nominal steam parameters.

Simultaneously, variations in the steam parameters behind the boiler should not surpass allowable limits, specifically t=420-445 °Υ and P=3,4-3,9 MPa.

Considering GTU start-up and loading modes, HRSG should be adjusted to start-up from any temperature state.

The single-circuit, gas-tight, drum-type, vertical (along the gas flow), steam recovery boiler (SRB) is made to function under pressure.

A gas-water heater (GWH) is a feature of CHP that lowers the temperature of flue gases behind the boiler and increases the efficiency of flue gas heat utilization.

The boiler’s common gas duct contains the steam superheater, evaporator, economizer, and HRSG in that order along the gas flow.

It is necessary to account for the possibility of HRSG functioning with GWP disconnected by water.

View 2 of HRSG over GTU

It is not permitted to operate the gas turbine during the HRSG shutdown.

The boiler is supported by its own frame, which bears loads from the boiler shell, chimney, drum, heating surfaces, and pipelines.

There are openings in the boiler shell that allow access to the heating surfaces.

The HRSG equipment can be serviced using the ladders and platforms that are available.

In compliance with standard requirements, the boiler design also offers conditions for the mechanized repair of its components.

Compensating devices are installed at the boiler’s exhaust gas input from GTU.

The heating surfaces are completely empty.

All required shut-off, regulating, safety valves, and automated control systems are included with the HRSG.

Systems, drainage, steam, and water sampling are all included in the HRSG’s equipment.

A separate metal chimney is used to remove flue gas from the HRSG into the atmosphere.

At a distance of 1.5 meters from the floor and 1 meter from the shell, the equivalent sound level from the gas duct and HRSG does not surpass 80 dBA. A sound attenuator is installed at the gas turbine outlet to ensure certain noise characteristics.

The boiler’s exterior surfaces are insulated, and their temperature shouldn’t go above 45 oÑ.

Steam superheaters

The vertically finned tubes and connecting spigots that join the sections of the steam superheaters KVD and KND are welded together. Superheaters of steam will be emptied and made accessible for upkeep and repairs.

Under all operating conditions, the layout and design of the superheaters must guarantee a uniform distribution of steam inside the tubes and gas flow surrounding them.

The superheater tubes’ metallic design incorporates operating and system unbalance conditions. Each superheater’s pressure loss will not be greater than 5% of the maximum pressure at full steam capacity.

A system of injectable steam temperature control will be installed in the KVD superheater.

The two stages of the superheater heating surfaces are arranged to achieve the design temperature values without the need for additional control.

Temperature sensors, transducers, automatic wedge gate valves, injection steam temperature control valves, and system controls will all be installed in compliance with the given specifications. Every fitting required to guarantee the boiler’s overall regular, secure, and dependable operation will be installed.


The maximum loads and moments that can be applied to the connection points of the plant’s component parts are taken into consideration during the design of the piping system, which aims to provide dependable and seamless operation.

Welded construction systems are to be prioritized. When flanges are needed to join equipment components, the proper kind of connection surface will be supplied.

Pipeline interior diameter selection will be based on allowable speeds and average parameters.

There will be drainage systems in the lower portions of the pipelines and venting systems in the upper sections. To enable full venting or drainage, the pipelines will be outfitted with electric-actuated fittings, a valve system, and condensate collectors.

The diameter of the drainage funnels will be sufficiently large to guarantee a snug fit of the covers. In order to verify the drainage system’s operation, drainage lines will be placed into funnels.

Installing specialized drainage devices stops condensation buildup in the pipe system. Where dew points are anticipated to be reached, a cased condensate collection system with manually operated valves will be installed.

There will be anchorages, pipe supports, and pipe guides for the piping system. The piping will be positioned far enough away from the floor, walls, and other pipes in the enclosure to provide access for welding joint testing and maintenance, as well as the use of thermal insulation.


The required number of manifolds and their location will ensure maximum convenience of their use and maintenance.

All pipe bundles will have uniform distribution of water and vapor flow thanks to the design of the distribution and collection headers. They’ll make sure the pipe bundles can expand freely. The pipe manifolds’ design facilitates internal surface cleaning and pipe replacement. It might be necessary to cut several tubes in order to fix a damaged tube that is a part of a single module.

The boiler drum will have pipes outside that connect the tube bundles to the headers. The EN standards will be followed in determining the collectors’ design temperature.

During transportation, storage, and installation, the ends of tubes, manifolds, and other exposed pressure parts will be sealed to keep out foreign objects and cleaned of soot and other compounds. To enable inspection and thorough removal of cleaning agents, these parts won’t be sealed during the cleaning process.

In the fabrication shop, all spigots and fittings will be welded to the manifolds.

The manifolds will have drainage equipment installed and, if feasible, be the same length as seamless tubing.

The outlet headers’ construction will enable them to absorb thrust and bending moments from the pipelines that are attached.

Permanent instrumentation will be supplied along with pressure test sockets, thermometer wells, temperature recording devices, and test samples needed for complete boiler testing.

Babcock Wanson HRSGs

Babcock Wanson has been designing and supplying its customers with waste heat recovery boilers of various applications and capacities for over a century. All Babcock Wanson HRSGs are fully compliant not only with customer requirements but also with international codes and standards. Boilers are designed taking into account the temperature and pressure of both flue gases and heat carrier (water or oil).
All boilers manufactured by Babcock Wanson are very easy to install, as they are produced ready to connect to all utility networks and set up for commissioning. They have special spigots or openings for feeding the flue gases into the boiler and for connecting the coolant inlet and outlet piping.
Thanks to this, the installation of Babcock Wanson waste heat recovery boilers can be done very quickly and will start to bring profit from the first seconds of commissioning.
For questions related to the equipment of BABCOCK WANSON company you can contact the official representative office in the Russian Federation LLC "SETAL".

Application of utilizer boilers GTU, CHPP

To extract the majority of the heat from the working units and turn it into electricity, many utilizer boiler modifications are installed; one such modification is the use of a boiler utilizer thermal power plant boiler.

These boilers are used in open-hearth production, which includes the steel and chemical industries and any other type of production that generates waste exhaust gas.

Remember this: occasionally it may not be profitable to convert waste or utilized gases into energy. For instance, in the production process using welding of the inverter type.

The equipment emits a small amount of gases, and using it is not always recommended.

Utilizers use charge gas, a gas-cloud mixture that contains finely dispersed solid impurity particles, which are essentially the fuel, for combustion.

The purpose of DSA atmospheric deaerators is to eliminate caustic gases from steam boiler feed water.

Find out here how to install a deaerator correctly.

The source of the gas’s ignition is these tiny particles, which glow with the electrode and create an environment of high temperature around them.

This is the primary design element shared by all gtu utilizer boiler varieties. Metal scale, oil mist, tiny oil film particles, rubber residue, and rubber traces are examples of solid inclusions.


The utilizer boiler’s design is made up of:

  1. Blower fans, the function of which is to supply air; there is a dual-mode control for the fans:
  2. automatic by means of a control unit;
  3. manual;
  4. A safety valve;
  5. The loading chamber used for fuel stacking, pyrolysis gases are generated in it. Heat-resistant material is used for its manufacture. Attached door sealed for safe operation, an optional door with viewing window is also provided;
  6. The combustion chamber where the pyrolysis gases are burned; it is made of sheet steel;
  7. Ozonator (the second chamber where pyrolysis gases burn);
  8. Burners and flare traps located between the two chambers; Gases are fed through the burner; Gas, air and ozone are combined;
  9. Heat exchanger, which takes all the heat produced by the water jacket and transfers it to the heat transfer medium;
  10. Chimney valve, providing additional fuel loading without smoke;
  11. Canopy (for outdoor installation).

Heat-resistant materials are used in the construction of every structural component where combustion occurs. Additional accessories, such as a backup source of continuous power supply in case of frequent power outages, may be included based on design specifications and buyer preferences.

It is important to note that when there is no oxygen available, a process known as smoldering occurs. This process raises the unit’s temperature, lengthens the interval between fuel loads, and eliminates smoke from the output.

Options of waste gas utilization boilers

In industry, gas-tube waste heat recovery boilers are commonly utilized. The boilers run on the thermal energy contained in the flue gases. The fuel line or any other networks supplying the energy carrier are not connected to such a device. The boiler must be installed where the outlet section is in order for the energy to be used as efficiently as possible.

Utilizer boilers generate energy by using the heat from waste flue gases, which are byproducts of production.

Waste gas-using boilers are more efficient than standard boilers, which lowers the amount of harmful emissions released into the atmosphere.

Both domestic and foreign manufacturers sell boilers. Because the gases travel through the pipes, the heat carrier gets heated. Steam with low to medium pressure is produced using this kind of equipment.

Variants of boilers:

  • Has natural or forced circulation.
  • The composition includes one or several drums.
  • Boiler models can be gas tube or water tube boilers.

The cat’s design consists of a steel body, a collection of heat-resistant tubes, surfaces that heat and evaporate, feed water fittings, and a system to eliminate extraneous gases. Boilers for recovery can be horizontal or vertical. The location of the equipment will determine which model is selected. An efficient waste heat boiler powered by rubber is one that uses pyrolysis.

Types of equipment

There are two primary categories of utilizer boilers in total:

  • 1. Steam, which uses energy from gaseous water. Then condensation occurs on its walls, and the liquid returns to its usual state for normal conditions. The water can then be used for mechanical work, although this will not be relevant for the house.
  • 2. Waste gas utilization boilers, which work on the principle described above. It is only worth adding that in industry, the fuel burned often also emits large amounts of soot into the atmosphere as a waste product. Its presence will be unacceptable for the utilizer, so it will be necessary to put an additional filter on the smoke route. It will clog very quickly, so you will have to clean it about once a week.

The effectiveness and utility of a given technique’s application determines its appropriateness. With only 50% efficiency, the utilizer boiler is not a suitable choice for a heating system. However, it should be remembered that thermal energy is produced without the use of any resources at all. Waste is the source of all usefulness; without the user, it would just be thrown into the atmosphere.

Then, despite the fact that the payback will take several years, it appears that installing it was highly justified. It is also important to consider the benefits to the environment. Since air pollution is now a global issue, it is important to take advantage of any chance to lessen its detrimental effects, even if they are only local.

The factory-produced boiler that is being used will cost more than thirty thousand rubles. You can invest between $12,000 and $15,000 if you decide to build the machine yourself. Not every business chooses to upgrade to an industrial unit because they can cost up to half a million rubles in general.

Control unit

The water pump and fans are controlled by the automatic control unit. To select the menu, just one button needs to be pressed.

The unit has a room thermostat connected to it so you can keep the temperature where you want it.

This unit emits a sound signal in the event that the fuel runs out or the temperature rises above 90 °C. The temperature at which the fan starts and stops the boiler to add fuel can be adjusted with it.

Its benefits include the ability to control the boiler’s primary components and seamless operation. It is also activated in the case of an mishap.

A wise decision if you want to save costs and protect the environment is the utilizer boiler.

View the video where a user walks you through the operation of a domestic waste heat boiler:

  • 1 Principle of operation
  • 2 Accessories
  • 3 Fuel resources
  • 4 Multifunctional protection
  • 5 Control unit

Main characteristics of the units

The casing is made of thick steel sheets – up to 15-20 mm. For the internal combustion chambers, a stronger alloy can also be used, which will depend on the intensity of the planned workflow. For circulation circuits, pipes with a diameter of up to 30 mm and a wall thickness of about 2-3 mm are usually used. In terms of operational capability, the key parameter is the temperature limit. At the inlet this value can be 300-1200 °C. After the completion of the technological process at the enterprise, its furnace gives off process gases with these indicators. At the output temperature characteristics of utilizer boilers are reduced to 150-200 °C, while the operating pressure can be up to 50 atm. Therefore, the design must be calculated not only for thermal, but also for the physical stresses of high-pressure operation. Depending on the model, the utilizers can also perform the tasks of heating water with steam. For example, as DHW equipment, a combined boiler system prepares the heating medium up to 80-100 °C.

Design and operating principle

Boilers with medium- or high-pressure steam are used in combined-cycle units. Steam is used in the steam turbine after it has been produced. A combined cycle plant uses exhaust gases as an energy source in addition to steam.

The design of steam-gas equipment allows for multiple forced-type circulation and water-tube boilers with convective heating surfaces. The steam turbine capacity indicator determines the design data for the heating unit. Depending on the model, there may be one circuit or multiple separate circuits with varying steam pressure values.

The three-circuit utilizer boiler’s design consists of:

High, medium, and low pressure steam superheaters, secondary steam superheaters, high, medium, and low pressure evaporators, high, medium, and low pressure economizers, condensate gas heater, frame, service platforms, insulation, and cladding are all included in the drums with high, medium, and low pressure separation devices.

Every heating surface is composed of drained spiral-finned tubes. The boiler has all of the required fixtures, fittings, and equipment.

Figure 1: Hotel-Restaurant Operator ΚГТ-258/310/35-15.0/3.14/0.44-540/535/263

Boilers of the PKK type, which are utilized for combining waste gases from the production of steam and soot, are positioned behind furnaces that heat up to a high temperature and provide unified energy.

PKK type boilers are constructed in a U-shape and are single-drum, convective, with natural circulation.

In the unshielded preheater, high-calorie fuel and flue gases are burned together. Combustion products flow from the preheater into the rising gas duct, which contains sections of the convective bundle. These sections are made up of screens made of pipes that are connected by separate inlet and outlet headers. The screen sections are attached to the drum 8 by steam exhaust pipes that hang from the boiler ceiling. The metal frame, which is welded together, supports the drum installation.

Depending on the boiler capacity, a steam superheater made up of one package (PKK-30 boiler) or multiple packages (PKK-100 boiler) is located in the area created by the bend of the convective beam screen sections.

The downstream gas duct contains a steel water economizer and a vertical tubular air heater. There are three packages in the economizer. The surfaces in the lifting gas duct that are heated are cleaned using OT-type blowing devices, while the surfaces in the outlet gas duct are cleaned using a shot blasting unit. The boiler and furnace lining is composed of three layers of brickwork. Boilers of the PKK type are available in three different capacities: 30, 75, and 100 t/h steam. They are delivered in portable units.

Fig. 1: PKK type HRSG pre-furnace, gas passageways (10), steam superheater (3), Screens four, collector five 6-steam pipelines, 8 drums, 7 frames Blasting unit #9, air heater #11, and economizer #12.

Safety fittings

Every shut-off valve will be chosen and installed in compliance with the current TRD standards edition (or its equivalent in the EU) and the relevant normative documentation of the Russian Federation.

Pipelines for the discharge system’s safety valves will be positioned so as to prevent potentially harmful impacts on people and other plant equipment, with a minimum height of three meters measured from the top of the support structure.

Safety valves are made to withstand high pressures and damage to pressurized systems in a variety of operating scenarios, including dynamic operations. Silencers will be installed in safety valve pipelines that divert.

Equipment classifications

There are various fundamental kinds of equipment that are considered:

  1. Secondary gas temperature at the boiler unit inlet.
  2. Steam parameters.
  3. Organization of mutual movement of steam and water.
  4. Circulation in the evaporator circuit of the boiler.
  5. Structural design depending on layout and heating surfaces.

Boilers classified as low-temperature (with secondary gas temperatures below 900 degrees Celsius) or high-temperature (with temperatures exceeding 1000 degrees Celsius) are the first characteristics that boilers use.

Heat transfer happens through convection in low-temperature boilers and radiation and aggregate state change in high-temperature boilers.

Depending on the secondary gas composition and the boiler unit’s device, water-heating boiler utilizers can be constructed with single- or multiple-forced circulation.

The working principle of recovery boilers is as follows: they produce energy in the form of steam, heated water, or air flow.

You can find out more about gas utilizer boilers by visiting

There are four types of construction designs: radiation-convective, tower, U-shaped, and horizontal tunnel.

Consideration should be given to the technological aspects of production in design and installation, where hot gas supply is cyclical.

Furthermore, these cycles aren’t always precisely timed and synchronized. As a result, these devices are highly automated and can swiftly record every aspect of the gas flow based on volume and temperature.

Working principle

The utilizer boiler works on the basic principle of gathering gaseous exhaust waste and extracting as much heat energy as possible from it. The apparatus lacks a direct combustion process and a furnace of its own. It is employed in industrial settings where there is a sufficient volume of gaseous waste to support the efficient operation of such devices.

At first glance, the calculation of such a boiler for domestic needs does not appear to be very promising. The main argument is that insufficient fuel is burned to enable significant reductions in the usage of flue gases. However, a hybrid unit that runs on both emissions into the atmosphere and combustible fuel can be built.

One can view the scheme and device of this technique online.

Building a technique of this nature will require a significant number of tools and consumables, so careful planning and preparation are necessary to ensure that nothing crucial is overlooked and the process cannot be continued during the work.

The utilizer boiler’s design suggests the inclusion of an extra section where exhaust gases are gathered, their thermal energy is extracted, and it is then transferred to the heat carrier. The apparatus will only be 30 to 40 centimeters higher; its dimensions do not increase significantly. For the most part, this has no bearing on the user.

The economic impact of this endeavor is hard to forecast because there are so many variables at play that are very challenging to figure out before the tests begin. It will, however, most certainly not be worse than it is; this much is certain. The most important thing is to follow the instructions precisely so that the smoke is gathered in a designated area and then silently removed once it has cooled. Combustion products will find their way into the room through any leaky joints.

The operation of CCGT in conjunction with a waste heat boiler differs slightly. This unique electrode installation in the collection chamber instantly afterburns all combustion products. Massive amounts of energy are released as a result of the process. However, this method is only useful on an industrial scale because boilers can operate at temperatures as high as 1300 degrees Celsius. Heat-resistant materials must be used, which is harder to come by in domestic settings and even harder to work with. For the sake of a tiny savings, safety should never be compromised.

The utilizer hot water boiler is installed in the space between the main heater and the chimney. In this instance, having a turbine installed on the exhaust system is preferable. As a result, smoke will reach recycling facilities more quickly, and transportation energy losses will generally be reduced. As the majority of useful properties are lost during movement, expediting the delivery process will only help you. This is supported by statistics.

Symbols and abbreviations

  • 3-circuit HRSG – HRSG;
  • GTU – gas turbine plant;
  • ATS – automatic reserve input;
  • HDB – high pressure drum;
  • BSD – medium pressure drum;
  • HDB – low pressure drum;
  • GPD – main steam gate valve;
  • PPVD – high pressure superheater;
  • HVD – high pressure evaporator;
  • EVD – high pressure economizer;
  • PPVD – medium pressure superheater;
  • ISD – medium pressure evaporator;
  • ESD – medium pressure economizer;
  • LSP – low-pressure steam superheater;
  • secondary superheater – secondary steam superheater;
  • IND – low pressure evaporator;
  • GPC – gas condensate heater;
  • WGW VD – high pressure regulating feed valve;
  • RPK SD – medium pressure regulating feed valve;
  • RPK ND – regulating feed valve of low pressure;
  • RPP – periodic blowdown expander;
  • RPV – continuous blowdown expander;
  • REN – recirculation electric pump.

Principle of operation of water tube boilers

The same presumption applies to heating a liquid and producing steam, but in this instance, the economizer supplies the water carrier. It then moves on to the heating drum, where steam is produced. The process of generating heat takes place in the receiving tank when the water and steam mixtures are separated. Depending on how the furnace source of the gas mixture, which the HRSG interacts with, is designed, the connection of various technological circuits to the drum can be made either sequentially or in parallel. The principle of operation also entails the transfer of water to evaporation packages after it has passed through filtration in the sludge separator.

Metal structures, supports and platforms

Platforms for HRSG services

In addition to the dead weight of the machinery, accessories, water, snow, people, force applications and their moments in pipes, ladder and platform weights, and other loads that arise during regular plant operations, the metal structures must be able to withstand seismic loads.

The boiler supports’ design ought to permit the elements’ unrestricted downward expansion. Factory painting will be applied to all support structures, such as columns, walers, beams, struts, pads, and posts.

Pads to center the tubes and reduce vibration in the tubes will be installed in the boiler.

The materials used to make the supports will always be able to withstand the highest temperature at which they are intended to be used.

At least one meter wide spans, ladders, and service platforms will make it easy for workers to perform maintenance, repairs, and inspections. Inlet openings for inspection and test work, components needing continuous monitoring or maintenance, and devices requiring manual operation in regular or emergency operating modes will all be safely and quickly accessible with the help of ladders and platforms. Grids and steel frames will be used to build the platforms. Guardrails will be installed on ladders and platforms in consideration of the heaviest components that might be used on them during maintenance, repair, etc.


There won’t be any gas bubbles, fouling, or other mechanical flaws in any of the seamless round tubing. The entire circumference of the tubes will have ribs welded onto them. The fins’ and the tubes’ respective materials are compatible.

Welded tube ends, which include factory-installed short tubes in drums or manifolds, will undergo meticulous machining to guarantee a high-quality welded joint and guard against rusting or damage during transit. Every pipe will be precisely bent to the necessary angles without the pipe walls at the bends flattening or significantly thinned.

Heat-receiving element modules will pass hydraulic testing at the factories of the manufacturers.

Advantages of the equipment, applications

Let’s examine the primary benefits and drawbacks of HRSGs.


Negative aspects

The chemical, steel, oil refining, heavy engineering, paint, and oil production industries all make extensive use of these units.

These kinds of boilers are capable of using gas produced during the burning of fuel, which provides ideal conditions for the setup of waste-free, cyclic production using energy recirculation.

In comparison to their liquid or solid fuel counterparts, the units have a very high efficiency because they only use exhaust or associated gas.

HRSGs can be classified structurally as either forced or natural circulation boilers, with or without a drum. Furthermore, proficient designers and technologists work on developing boilers of all kinds while considering the unique needs of the client and the equipment that boilers require.

Boilers with various supply and circulation schemes, power characteristics, heating tank volumes, and vaporization register counts are utilized in industry, contingent upon the production cycle.

One benefit of diesel boilers is that the boiler room retrofitting will be relatively inexpensive if the object is gasified later on.

Learn more about the potential flow rate of a diesel boiler.

Practical application of HRSGs

As a real example of application of waste heat recovery boilers it is possible to give oil refineries and metallurgical plants. In the process of oil refining or metal smelting a huge amount of energy is generated, which can not be used in the production process except for the waste heat boiler and used for other purposes, such as space heating, hot water supply (HTW), air conditioning (cold production), or steam production to cover third-party technological needs.At refineries are used thermal oil boilers utilizers, in which the temperature of the coolant can reach 350 degrees Celsius. This temperature is sufficient to keep high-viscosity petroleum products such as fuel oil, tar and bitumen in a liquid state at all times. This makes it possible to pump petroleum products at any time and ship them to the consumer.
In metallurgical plants, waste gas heat is transferred to water by means of utilization boilers. As a result, a large amount of steam is generated, part of which is used for steel melting process and part of which is used for domestic needs (heating, water heating).

HRSGs are now a crucial component of the following establishments:

  • Enterprises of ferrous and non-ferrous metallurgy;
  • Oil refineries;
  • Gas turbine and gas piston power plants with unit capacity from 1000 kW to 18 MW;
  • Gas compressor stations;
  • Baking plants;
  • Manufacture of rubber products;
  • Pharmaceutical enterprises;
  • Production of resins and plastics;
  • Production of electronic components;
  • Printing companies.

Field of application

For the production of chemicals and coke, this equipment is especially crucial. Dry extinguishing red-hot coke releases a significant amount of physical heat, which means that less conventional fuel must be used.

Convertor Hot carbon gases are treated in steelmaking using gas cooler boilers. By forcing oxygen through convectors, they are created.

These boilers lessen atmospheric air damage and convection entrainment. These are radiation-convective units with a two-stage evaporation plan and multiple forced circulation realized.

A carbon monoxide afterburn occurs in certain modifications, but not in others.

Modernized HRSGs, which are used for combined cycle plants at thermal power plants, have just lately come into use.

Plans for preparing feed water for steam boilers and make-up water for heat supply and hot water supply systems at TPPs and boiler houses employ atmospheric pressure deaerators.

Learn more about vacuum deaerators here.

They make use of secondary gases that are emitted when the gas turbine runs. There are substantial fuel savings as a result of reusing the medium- and high-pressure steam that is produced in the turbine.

Cogeneration plants use boilers to use waste heat from gas turbines or reciprocating engines. Steam is produced during the process and used for hot water supply or heating purposes.

In the world of insulation and heating for your house, knowing how a boiler utilizer operates is essential. This clever system is the cornerstone of effective home heating because it works on a straightforward but very effective principle. To ensure that no energy is wasted, the boiler utilizer essentially captures the residual heat produced during a boiler’s combustion process. Through the astute utilization of this surplus heat, the system optimizes efficacy and reduces energy usage, providing financial and ecological advantages. For homeowners looking for cost-effective heating options, the boiler utilizer is a dependable and wise choice, whether it’s for heating water or sustaining a comfortable interior temperature.

Principle of operation of gas-tube and water-tube boilers

Gas turbine type utilizer

Boilers are typically manufactured in vertical or horizontal design variations.

When combined with open-hearth furnaces and kilns, which lack high power characteristics and high gas temperatures, they can be used effectively.

Low temperature gas enters the user’s lower cavity through the smoke extraction unit after leaving the furnace. The device-chamber is unique and enhances the convection characteristics.

The chamber is made up of a set of metal sheets that both direct and reflect heat flows. Overheating causes the water to release steam, which is then moved in the necessary directions.

Around 400 degrees Celsius and more than 5 atmospheres of pressure are typical values for steam, which enables the production of just over 8 kW of electrical energy.

The utilizer has a storage receiver and a mixture feeder to the igniter to maintain a roughly constant gas flow.

The principle of operation for all users equipped with a gas turbine is the same. They are frequently employed in installations with large capacities but low flue gas output to balance the temperature regime. It is economically feasible to use them.

Water tube type utilizer

Gas utilizers are widely used in the industry. They feature a forced circulation system for process liquids, heat, and steam.

With automation and control relays, forced circulation makes it possible to raise the steam’s temperature and power.

The boiler’s chambers are segmented into smaller sections, each having its own low-power circulation pump.

It enables the independent accumulation of thermal energy in each chamber, which is then combined with the aid of reflectors to produce steam and electric energy.

An economizer, a dosing device, allows heated water to enter the chambers, which is necessary for the formation of steam.

Water exits the chambers and enters designated evaporation areas, which are sealed chambers with holes to remove heat.

Protherm electric wall-mounted boilers offer a number of indisputable benefits as an alternative to gas heating!

Click this link to learn more about dv deaerator.

The majority of the heat from the units is removed, the generated thermal energy lowers the temperature of the gas mixture as a result of its transformation, and it also provides ideal conditions for energy-efficient production methods.

There is a single typical pattern for almost all boilers.

Recyclers are only recently being used in production, but even in their early phases, they have provided great foundations for lowering expenses and raising output.

It is a tried-and-true kind of machinery that works well with large and medium-sized capacities, enhancing them both.

Fuel resources

Peat, coal, and firewood are not the only fuel options for these boilers.

A range of wastes can be used in pyrolysis boilers, and their efficiency can range from 80 to 96% depending on the energy carriers used.

The fuels listed below are appropriate:

  • wood and wood waste, chipboard pieces, sawdust, trimmings, bark, sleepers, painted boards;
  • rubber waste, tires from any car, waste from the production of rubber products;
  • plastic containers, packaging materials, plastic scraps, waste from plastic production, housing products;
  • leather, dermantine, rag waste, residues from the production of clothing, footwear;
  • paper, cardboard;
  • construction waste, bituminous pieces, roofing felt.

Types of waste heat recovery boilers

Utilizer boilers in operation right now:

  • General purpose exhaust gas utilization boilers.
  • Boilers that produce steam that drives mechanisms to generate electrical energy or simple mechanical motion.
  • For utilization of by-products from diesel combustion.
  • Boilers that are combined with heating furnaces and open-hearth furnaces, the heat energy and associated gases are converted in the boilers into additional energy or useful work.
  • Devices that cool associated gases, using them in the work by condensing and combustion method. Used in the metallurgical industry.
  • For condensation and combustion of gases when used in non-ferrous metallurgy.
  • To process the heat gas obtained during the operation of electric furnaces.
  • Combination boilers, which are used to utilize or convert the heat energy that is produced during the perforation of steel and iron in the foundry industry.
  • Utilizers used for afterburning of gas that is generated during the initial stages of oil refining.
  • Utilizing boilers for gas that is generated in the process of welding and fire works.
  • For furnaces after sponge metal production.
  • Boilers that burn sediments and impurities obtained during the filtration of liquid substances.
  • Utilization by annealing soot and carbon black in boilers.
  • Utilization of coke and black coal waste in boilers.
  • Disposal from glass production and glass industry operations.

Boilers that burn for a long time are used to maintain the boiler’s temperature.

See How to Use a Boiler for Hot Water.

Features of the equipment

The boiler used by the user does not have a separate furnace chamber. Heat from other technological processes is used by such a unit.

Be mindful! It makes sense to burn the last one when the output gases contain both a chemical and a physical component of heat.

The presence of numerous tiny particles in the output gases is a defining characteristic of industrial utilization systems. They can be gaseous, solid, or liquid. Particles are the result of production plants operating; they can be scale, slag, charge, or pieces of metal. Smelting metals produces liquid particles. These micro-wastes are typically produced as a result of the high temperatures involved in metal processing procedures.

The way waste is fed into the heating unit, how much heat it produces, and its temperature all affect how well exhaust gases are used. The amount of fuel burned and the type of industrial process determine the temperature and volume of exhaust gases. When oxygen is blown into converters in both ferrous and non-ferrous metallurgy, a sizable amount of charge gases are produced.

The utilization boiler’s forced circulation scheme is as follows: Water economizer (number four); steam superheater (number three); drum (number two).

As previously mentioned, the manner in which the utilizer receives its gas supply has a significant impact on how the utilizer operates. Industrial machinery, particularly converters, frequently operates in cycles, which has a negative impact on the boiler unit’s productivity.

The following criteria can be used to categorize the utilizer boiler:

  1. By the temperature of the gas supplied to the unit. According to this parameter the equipment is subdivided into: low-temperature (less than 900 degrees) and high-temperature (over 1000 degrees). At low temperatures, the transfer of heat energy is realized through convection, and at high temperatures – in the process of radiation. At temperatures exceeding 1100 degrees, liquid combustion products change their aggregate state.
  2. According to steam characteristics utilization boiler can belong to 3 classes: equipment with low pressure (1.5 MPa and 300 degrees), with increased pressure (4.5 MPa and 450 degrees), and with high pressure (from 10 to 14 MPa and 550 degrees).
  3. According to the principle of movement of liquid, steam and combustion products, utilization boilers are divided into two types: gas-tube and water-tube boilers.
  4. According to the method of liquid movement in the evaporator circuit utilizing equipment is differentiated into boilers with natural and forced circulation.
  5. According to the configuration and heating surfaces, the equipment is subdivided into such types: tower, horizontal and tunnel type. In low-temperature devices a coil convective heating surface is used. In high-temperature modifications – convection-radiation surface.

A straightforward but incredibly efficient system for home insulation and heating is the boiler utilizer. It works on the basis of collecting boiler waste heat and using it to heat buildings and produce hot water, which increases energy efficiency and lessens the impact on the environment.

The boiler utilizer’s ease of use is one of its main benefits. It increases the heating system’s efficiency by retaining heat that would otherwise be wasted, all without the need for sophisticated technology or extra energy. Homeowners can save money because less energy is required to achieve the same level of comfort thanks to this simplicity.

Furthermore, the boiler utilizer’s efficiency supports environmental sustainability. It lessens carbon emissions and lessens the effects of using fossil fuels by lowering the amount of fuel required to heat a home. This is especially important in the modern world, where worries about climate change are becoming more pressing.

Beyond just saving energy, the boiler utilizer has other useful advantages. It improves the general comfort and convenience of a household by offering a dependable source of heat and hot water. Both an increase in property value and a better quality of life for the occupants may result from this.

To sum up, the boiler utilizer is a straightforward yet effective way to heat and insulate homes. For homeowners seeking to improve comfort and sustainability in their living spaces, it is a compelling option due to its cost-effectiveness, environmental benefits, and efficient operation.

Video on the topic

HRSG of sulfur production unit

How the utilizer boiler works. Efficient heating with MUSSOR

Utilizer boiler

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Sergey Ivanov

I like to help people create comfort and comfort in their homes. I share my experience and knowledge in articles so that you can make the right choice of a heating and insulation system for your home.

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