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Types of Steam Turbine

Steam turbine is classified into several types based on their design, operating principles, and applications. Each type of steam turbine has its own characteristics and is suited for specific purposes. Here are the primary types of steam turbines:

  1. Impulse Steam Turbines:
    • Pelton Wheel Turbine: Pelton wheel turbines are used for high-head hydroelectric power generation. They use the impulse force of high-pressure jets of water to drive the turbine blades.
  2. Reaction Steam Turbines:
    • Axial-Flow Steam Turbine: Axial-flow turbines have blades that rotate about the turbine’s axis, and steam flows axially through the blades. They are commonly used in aircraft engines and some power generation applications.
    • Radial-Flow Steam Turbine: Radial-flow turbines have steam flowing radially outward from the center to the periphery of the turbine. They are used in small-scale power generation and some industrial processes.
  3. Condensing Steam Turbines: These turbines are designed to operate with steam at high pressure and temperature, and they exhaust the steam at a lower pressure and temperature. The exhaust steam is condensed back into water for maximum energy extraction.
  4. Back-Pressure Steam Turbines: Back-pressure turbines are used to exhaust steam at a pressure higher than atmospheric pressure. They are often used in industrial processes where high-pressure steam is required for heating or other purposes.
  5. Extraction Steam Turbines: Extraction turbines, also known as extraction condensing turbines, extract steam at intermediate pressures for use in industrial processes, heating, or district heating. They are often used in combined heat and power (CHP) systems.
  6. Mixed-Pressure Steam Turbines: Mixed-pressure turbines operate with steam extracted at multiple intermediate pressures. They are suitable for applications that require a combination of high-pressure and low-pressure steam.
  7. Single-Stage Steam Turbines: These turbines have only one set of rotating blades (rotor) and a single stage for steam expansion. They are relatively simple and are often used in smaller-scale applications.
  8. Multi-Stage Steam Turbines: Multi-stage turbines have multiple sets of rotating blades (rotors) and stationary blades (stators) arranged in sequential stages. Each stage extracts energy from the steam, leading to higher efficiency. They are commonly used in large-scale power generation.
  9. Curtis Steam Turbines: Curtis turbines are a type of impulse turbine that uses multiple stages to expand the steam. They are often used in industrial applications and power plants.
  10. Rateau Steam Turbines: Rateau turbines are a type of reaction turbine that uses fixed and moving nozzles to expand the steam in stages. They are commonly used in marine propulsion and power generation.
  11. Kaplan Steam Turbines: Kaplan turbines are axial-flow turbines used for low-head hydropower generation. They are designed to operate efficiently with large flow rates of low-pressure steam or water.
  12. Francis Steam Turbines: Francis turbines are a type of reaction turbine used for medium-head hydropower generation. They are versatile and can handle a wide range of flow rates and pressures.

The choice of steam turbine type depends on various factors, including the application, required power output, steam conditions, and efficiency goals. Each type of steam turbine is designed to optimize performance for specific operating conditions and requirements.

Types of Steam Turbine

There are several types of steam turbines, each with its own advantages and disadvantages. The most common types of steam turbines are:

  1. Condensing Turbines: Condensing turbines are the most common type of steam turbine. They work by extracting all of the steam from the turbine at the end, condensing it into water. This allows for the highest possible efficiency, as all of the energy in the steam is extracted. However, condensing turbines require a large amount of cooling water, which can be a major limitation in some applications.
  2. Non-Condensing Turbines: Non-condensing turbines do not condense all of the steam. Instead, they extract some of the steam at an intermediate point in the turbine and use it for process heating or other purposes. This allows for more flexibility in the use of steam, but it also reduces the efficiency of the turbine.
  3. Back-Pressure Turbines: Back-pressure turbines are a type of non-condensing turbine that is designed to operate at a specific back pressure. This means that the steam is not condensed, but it is exhausted at a specific pressure. Back-pressure turbines are often used in industrial applications where process steam is required at a specific pressure.
  4. Reheat Turbines: Reheat turbines are a type of condensing turbine that has an additional stage in which the steam is reheated before it enters the final stages of the turbine. This increases the efficiency of the turbine, as it allows for more energy to be extracted from the steam.
  5. Mixed Pressure Turbines: Mixed pressure turbines are a type of turbine that can use both high-pressure and low-pressure steam. They are often used in industrial applications where there is a need for both power and steam.
  6. Geared Turbines: Geared turbines are a type of turbine that has a gearbox between the turbine shaft and the generator. This allows for the turbine to operate at a higher speed than the generator, which can improve efficiency.
  7. Axial-Flow Turbines: Axial-flow turbines are the most common type of steam turbine. They work by having the steam flow along the axis of the turbine shaft. This allows for a more compact design than other types of turbines.
  8. Radial-Flow Turbines: Radial-flow turbines are a type of turbine that has the steam flow radially from the center of the turbine shaft to the outside. They are often used in smaller applications where space is limited.
  9. Impulse Turbines: Impulse turbines are a type of turbine that works by having the steam strike a series of blades. This transfers energy from the steam to the blades, which causes them to rotate.
  10. Reaction Turbines: Reaction turbines are a type of turbine that works by having the steam pass through a series of blades. This creates a pressure difference between the front and back of the blades, which causes them to rotate.

The choice of steam turbine depends on the specific application. In general, condensing turbines are the most efficient type of turbine, but they require a large amount of cooling water. Non-condensing turbines are more flexible, but they are less efficient. Back-pressure turbines are a good choice for applications where process steam is required at a specific pressure. Reheat turbines are more efficient than condensing turbines, but they are more complex and expensive. Mixed pressure turbines can use both high-pressure and low-pressure steam, making them a good choice for industrial applications. Geared turbines are a good choice for applications where space is limited. Axial-flow turbines are the most common type of steam turbine, while radial-flow turbines are often used in smaller applications. Impulse turbines are a good choice for applications where high efficiency is required, while reaction turbines are a good choice for applications where low cost is important.

Impulse Steam Turbines

Impulse Steam Turbines
Impulse Steam Turbines

Impulse steam turbines, also known as impulse-type turbines, rely on the direct transfer of kinetic energy from steam to the turbine blades. In contrast to reaction turbines, where the steam interacts with both the fixed and moving blades, impulse turbines solely utilize the momentum of steam jets impinging on the moving blades.

Working Mechanism

  1. Steam Expansion and Nozzle Passage: High-pressure steam enters the turbine through a nozzle, where it undergoes significant expansion and acceleration. The nozzle’s shape and size are carefully designed to control the steam flow and optimize the transfer of energy.
  2. Blade Interaction and Impulsive Force: The high-velocity steam jet from the nozzle strikes the buckets or blades of the rotor, imparting its kinetic energy to the blades. This impulsive force causes the blades to rotate, converting the kinetic energy of the steam into rotational motion.
  3. Blade Design and Angle: The design and angle of the blades play a crucial role in maximizing energy transfer. The blades are curved to deflect the steam flow, guiding it along a path that further enhances the impulsive force.
  4. Multiple Stages for Energy Extraction: Impulse turbines often employ multiple stages, each consisting of a set of fixed nozzles and moving blades. As the steam passes through each stage, it undergoes further expansion and imparts its energy to the blades, progressively extracting energy from the steam.

Advantages of Impulse Steam Turbines

  1. High Efficiency: Impulse turbines are known for their high efficiency, particularly at high steam pressures and speeds. Their simple design and direct energy transfer contribute to their efficient energy conversion.
  2. Adaptability to High Speeds: Impulse turbines are well-suited for applications requiring high rotational speeds, making them suitable for driving generators and other high-speed machinery.
  3. Reduced Blade Erosion: The direct impact of steam on the blades in impulse turbines can cause erosion. However, their simple blade design allows for easier maintenance and replacement.
  4. Versatility and Multi-Stage Design: Impulse turbines can be designed with multiple stages to accommodate a wide range of steam pressures and flow rates, making them versatile for various applications.

Applications of Impulse Steam Turbines

  1. High-Speed Power Generation: Impulse turbines are widely used in power generation plants to drive generators due to their ability to operate at high speeds and achieve high efficiency.
  2. Jet Engines and Rocket Propulsion: Impulse turbines have found applications in jet engines and rocket propulsion systems, where their high rotational speeds and efficient energy transfer are essential.
  3. High-Pressure Steam Applications: Impulse turbines are suitable for applications involving high-pressure steam, such as steam expanders and high-speed pumps.
  4. Marine Propulsion Systems: Impulse turbines were historically used in marine propulsion systems, particularly in smaller ships, due to their compactness and high rotational speeds.
  5. Industrial Applications: Impulse turbines are employed in various industrial applications, such as high-speed machinery drives, gas expanders, and air compressors.

Conclusion:

Impulse steam turbines offer a combination of high efficiency, adaptability to high speeds, and a simple design, making them a preferred choice for various power generation, propulsion, and industrial applications. Their ability to operate effectively at high steam pressures and speeds has led to their widespread adoption in diverse industries.

Reaction Steam Turbines

Reaction Steam Turbines
Reaction Steam Turbines

Reaction steam turbines, also known as reaction-type turbines, utilize the combined forces of impulse and reaction to extract energy from steam. In contrast to impulse turbines, where the steam solely impacts the moving blades, reaction turbines involve a more intricate interaction between the fixed and moving blades.

Working Principle

  1. Steam Expansion and Fixed Blade Passage: High-pressure steam enters the turbine through fixed blades, also known as stators or guide vanes. These fixed blades have a carefully designed shape that accelerates the steam flow and increases its kinetic energy.
  2. Steam Admission and Rotor Blades: The accelerated steam enters the moving blades, also known as rotors, where it further expands and imparts its energy to the blades. The curved shape of the rotor blades creates a pressure difference between their front and back surfaces, causing the blades to rotate.
  3. Reaction Force Generation: The combined effect of steam expansion and the pressure difference between the fixed and moving blades generates a reaction force that propels the rotor blades forward, converting the kinetic and pressure energy of the steam into rotational motion.
  4. Multiple Stages for Energy Extraction: Reaction turbines often employ multiple stages, each consisting of a set of fixed blades and moving blades. As the steam passes through each stage, it undergoes further expansion and generates additional reaction forces, progressively extracting energy from the steam.

Advantages of Reaction Steam Turbines

  1. Lower Blade Erosion: The combined impulse and reaction forces in reaction turbines reduce the direct impact of steam on the blades, minimizing erosion and wear.
  2. Higher Efficiency at Low Speeds: Reaction turbines are particularly efficient at lower rotational speeds, making them suitable for applications requiring moderate speeds and high torque.
  3. Suitable for Low-Pressure Steam: Reaction turbines can effectively operate with low-pressure steam, making them versatile for a wider range of steam conditions.
  4. Compact Design and Smooth Operation: Reaction turbines generally have a more compact design compared to impulse turbines and exhibit smoother operation due to the continuous interaction between the fixed and moving blades.

Applications of Reaction Steam Turbines

  1. Low-Speed Power Generation: Reaction turbines are often used in power generation plants for applications that require moderate speeds and high torque, such as driving large pumps or fans.
  2. Marine Propulsion Systems: Reaction turbines have been extensively used in marine propulsion systems, particularly in large ships, due to their ability to handle low-pressure steam and provide smooth operation.
  3. Industrial Applications: Reaction turbines are employed in various industrial applications, such as driving compressors, fans, and pumps in a range of industries.
  4. Steam Expanders and Auxiliary Systems: Reaction turbines are frequently used as steam expanders in industrial processes and auxiliary systems in power plants due to their efficiency and compactness.
  5. Combined Heat and Power (CHP) Systems: Reaction turbines are well-suited for CHP systems, where they can simultaneously generate electricity and provide steam for process heating or other industrial needs.

Conclusion:

Reaction steam turbines offer a combination of lower blade erosion, higher efficiency at low speeds, and suitability for low-pressure steam, making them a preferred choice for applications requiring moderate speeds and high torque. Their compact design and smooth operation contribute to their widespread use in power generation, marine propulsion, and various industrial applications.

Condensing Steam Turbines

A condensing steam turbine is a type of steam turbine that utilizes a condenser to remove the heat from the exhaust steam, creating a vacuum and increasing the turbine’s overall efficiency. This mechanism allows for the extraction of more energy from the steam compared to non-condensing steam turbines.

Working Principle of Condensing Steam Turbine:

  1. Steam Entry and Expansion: High-pressure steam enters the turbine through a nozzle or inlet valve, expanding and accelerating as it passes through the turbine blades. This expansion converts the steam’s thermal energy into mechanical energy.
  2. Mechanical Energy Transfer: The mechanical energy generated by the turbine blades rotates the turbine shaft, which can then be used to drive a generator or other machinery.
  3. Exhaust Steam Condensation: The exhaust steam from the turbine is directed to a condenser, where it is cooled and condensed back into water. This condensation creates a vacuum, reducing the exhaust pressure and allowing the turbine to expand the steam further.
  4. Feedwater Heating and Cycle Completion: The condensate from the condenser is then pumped back to the boiler, where it is heated and converted back into high-pressure steam. This completes the steam cycle, and the process can repeat continuously.

Advantages of Condensing Steam Turbines:

  1. Increased Efficiency: Condensing steam turbines achieve higher thermal efficiencies compared to non-condensing turbines due to the removal of heat from the exhaust steam. This allows for more energy to be extracted from the steam and converted into useful work.
  2. Lower Operating Costs: The higher efficiency of condensing steam turbines translates to lower fuel consumption and operating costs. This makes them more economical to operate in the long run.
  3. Environmental Benefits: By utilizing a condenser, condensing steam turbines reduce the amount of heat released to the environment, contributing to lower greenhouse gas emissions.

Applications of Condensing Steam Turbines:

  1. Power Generation: Condensing steam turbines are widely used for power generation in large-scale power plants. They are the primary technology for generating electricity from steam in these facilities.
  2. Industrial Applications: Condensing steam turbines are also used in various industrial applications, such as cogeneration systems, district heating systems, and process steam production.
  3. Marine Propulsion: Condensing steam turbines have traditionally been used for marine propulsion in ships, but their use has declined in favor of more efficient and environmentally friendly propulsion systems.
  4. Desalination Plants: Condensing steam turbines can be used to drive pumps in desalination plants, where they play a role in converting seawater into fresh water.

Conclusion:

Condensing steam turbines are a mature and efficient technology for converting thermal energy from steam into mechanical energy. Their higher efficiency and lower operating costs make them a preferred choice for power generation and various industrial applications. While their use in marine propulsion has diminished, they continue to play a significant role in various sectors, contributing to power production, industrial processes, and environmental sustainability.

Back-Pressure Steam Turbines

A back-pressure steam turbine is a type of steam turbine that is specifically designed to produce steam at a lower pressure for downstream applications, unlike condensing turbines which exhaust steam at very low pressures. Back-pressure turbines exhaust steam at higher pressure, typically between 5 and 20 psig (pounds per square inch gauge). This exhaust steam can then be used for various purposes, such as heating, process steam, or district heating.

Working Principle of a Back-Pressure Steam Turbine:

  1. High-pressure steam from the boiler enters the steam turbine.
  2. As the steam passes through the turbine’s stages, it expands, and its pressure decreases.
  3. This expansion converts the steam’s thermal energy into mechanical energy.
  4. The mechanical energy generated by the turbine is used to rotate a generator, producing electricity.
  5. The exhaust steam, still containing significant thermal energy, exits the turbine at a lower pressure.
  6. The back-pressure steam is then directed to downstream applications, such as heating systems, process steam requirements, or district heating networks.

Advantages of Back-Pressure Steam Turbines:

  1. Efficient Energy Utilization: Back-pressure steam turbines extract additional useful energy from the steam before it is discharged, improving overall energy efficiency.
  2. Reduced Fuel Consumption: By utilizing back-pressure steam for downstream needs, the demand for direct fuel combustion in boilers is reduced, leading to lower fuel consumption and cost savings.
  3. Environmental Benefits: Minimizing fuel consumption and utilizing waste heat from steam turbines contribute to reducing greenhouse gas emissions and minimizing the environmental impact of industrial processes.
  4. Versatility: Back-pressure steam turbines can be tailored to meet specific industrial or district heating requirements, offering flexibility in steam pressure and capacity.

Applications of Back-Pressure Steam Turbines:

  1. Industrial Process Steam Generation: Back-pressure steam is commonly used to provide steam for various industrial processes, such as papermaking, textile processing, and food production.
  2. District Heating Systems: Back-pressure steam can be used to heat buildings and provide hot water in district heating systems, replacing direct combustion of fossil fuels for heating purposes.
  3. Cogeneration Systems: Back-pressure steam turbines are often employed in cogeneration systems, where they simultaneously produce electricity and process steam, maximizing energy utilization.
  4. Steam Recompression: In some cases, back-pressure steam can be recompressed using a booster compressor to elevate its pressure, enabling its reuse in higher-pressure processes or for power generation.

In summary, back-pressure steam turbines play a crucial role in optimizing energy efficiency, reducing environmental impact, and providing valuable steam for various industrial processes and heating applications. By effectively utilizing back-pressure steam, industries and communities can conserve fuel, reduce emissions, and enhance the overall sustainability of their energy systems.

A back-pressure steam turbine is a type of steam turbine that is specifically designed to produce steam at a lower pressure for downstream applications. Unlike condensing turbines, which exhaust steam at very low pressures, back-pressure turbines exhaust steam at a higher pressure, typically between 5 and 20 psig (pounds per square inch gauge). This exhaust steam can then be used for various purposes, such as heating, process steam, or district heating.

How Back-Pressure Steam Turbines Work:

  1. Steam Inlet: High-pressure steam from the boiler enters the steam turbine.
  2. Expansion and Energy Conversion: As the steam passes through the turbine’s stages, it expands and its pressure decreases. This expansion converts the steam’s thermal energy into mechanical energy.
  3. Mechanical Energy Output: The mechanical energy generated by the turbine is used to rotate a generator, producing electricity.
  4. Back-Pressure Exhaust: The exhaust steam, still containing significant thermal energy, exits the turbine at a lower pressure.
  5. Downstream Utilization: The back-pressure steam is then directed to downstream applications, such as heating systems, process steam requirements, or district heating networks.

Advantages of Back-Pressure Steam Turbines:

  1. Efficient Energy Utilization: Back-pressure steam turbines extract additional useful energy from the steam before it is discharged, improving overall energy efficiency.
  2. Reduced Fuel Consumption: By utilizing back-pressure steam for downstream needs, the demand for direct fuel combustion in boilers is reduced, leading to lower fuel consumption and cost savings.
  3. Environmental Benefits: Minimizing fuel consumption and utilizing waste heat from steam turbines contribute to reducing greenhouse gas emissions and minimizing the environmental impact of industrial processes.
  4. Versatility: Back-pressure steam turbines can be tailored to meet specific industrial or district heating requirements, offering flexibility in steam pressure and capacity.

Applications of Back-Pressure Steam Turbines:

  1. Industrial Process Steam Generation: Back-pressure steam is commonly used to provide steam for various industrial processes, such as papermaking, textile processing, and food production.
  2. District Heating Systems: Back-pressure steam can be used to heat buildings and provide hot water in district heating systems, replacing direct combustion of fossil fuels for heating purposes.
  3. Cogeneration Systems: Back-pressure steam turbines are often employed in cogeneration systems, where they simultaneously produce electricity and process steam, maximizing energy utilization.
  4. Steam Recompression: In some cases, back-pressure steam can be recompressed using a booster compressor to elevate its pressure, enabling its reuse in higher-pressure processes or for power generation.

Conclusion:

Back-pressure steam turbines play a crucial role in optimizing energy efficiency, reducing environmental impact, and providing valuable steam for various industrial processes and heating applications. By effectively utilizing back-pressure steam, industries and communities can conserve fuel, reduce emissions, and enhance the overall sustainability of their energy systems.

Extraction Steam Turbines

An extraction turbine is a type of steam turbine that removes steam at one or more intermediate points along its length, rather than exhausting all of the steam at the end. The extracted steam is typically used for process heating or other purposes, while the remaining steam is used to generate electricity. Extraction turbines are more efficient than condensing turbines, as they make use of all of the energy in the steam.

Working Principle of an Extraction Turbine:

  1. Steam Entry and Expansion: High-pressure steam enters the first stage of the turbine through a nozzle or inlet valve, gaining velocity and decreasing pressure.
  2. Blade Interaction: The fluid strikes the rotor blades of the first stage, transferring its kinetic energy to the blades. This interaction causes the blades to rotate, generating rotational motion.
  3. Stage Transition: The partially expanded fluid exits the first stage and enters the second stage through intermediate passages or ducts.
  4. Repeated Expansion: The fluid undergoes further expansion and energy extraction as it passes through subsequent stages, each with its own set of rotor blades.
  5. Extraction Points: At one or more intermediate stages, a portion of the steam is extracted through extraction ports or openings. This extracted steam is used for process heating or other purposes.
  6. Remaining Steam Expansion: The remaining steam continues to expand and generate rotational motion as it passes through the final stages of the turbine.
  7. Exhaust Stage and Exit: The fully expanded and low-pressure steam exits the final stage through an exhaust port or nozzle. This exhaust steam can be condensed to recover water or used for other purposes.

Advantages of Extraction Turbines:

  1. Improved Energy Efficiency: Extraction turbines utilize the extracted steam for process heating or other purposes, maximizing energy utilization and reducing overall energy consumption.
  2. Enhanced Process Control: The ability to extract steam at various pressures allows for precise control of process temperatures and pressures, improving process efficiency and product quality.
  3. Reduced Fuel Consumption: By extracting steam for process needs, extraction turbines reduce the amount of steam required for power generation, leading to lower fuel consumption and environmental impact.
  4. Versatility and Adaptability: Extraction turbines can be tailored to specific process requirements by adjusting the extraction points and steam flow rates, making them versatile and adaptable to various applications.

Applications of Extraction Turbines:

  1. Industrial Process Heating: Extraction turbines are widely used in various industries for process heating, such as papermaking, chemical processing, and food processing.
  2. Cogeneration (Combined Heat and Power): Extraction turbines are often employed in cogeneration plants to simultaneously generate electricity and provide steam for process heating, achieving higher overall energy efficiency.
  3. Marine Propulsion: Extraction turbines were traditionally used in marine propulsion systems, particularly in large ships, to provide both power and steam for shipboard operations.
  4. District Heating Systems: Extraction turbines can be used in district heating systems to generate electricity and provide hot water for space heating and domestic purposes.
  5. ** desalination plants:** Extraction turbines can be used in desalination plants to generate electricity and provide low-pressure steam for the desalination process.

Overall, extraction turbines play a crucial role in various industrial and power generation applications, offering improved energy efficiency, process control, and versatility compared to condensing turbines. Their ability to extract steam for process needs enhances overall energy utilization and reduces fuel consumption, making them an environmentally friendly and sustainable technology.

EMS Power Machines

EMS Power Machines
EMS Power Machines

We design, manufacture and assembly Power Machines such as – diesel generators, electric motors, vibration motors, pumps, steam engines and steam turbines

EMS Power Machines is a global power engineering company, one of the five world leaders in the industry in terms of installed equipment. The companies included in the company have been operating in the energy market for more than 60 years.

EMS Power Machines manufactures steam turbines, gas turbines, hydroelectric turbines, generators, and other power equipment for thermal, nuclear, and hydroelectric power plants, as well as for various industries, transport, and marine energy.

EMS Power Machines is a major player in the global power industry, and its equipment is used in power plants all over the world. The company has a strong track record of innovation, and it is constantly developing new and improved technologies.

Here are some examples of Power Machines’ products and services:

  • Steam turbines for thermal and nuclear power plants
  • Gas turbines for combined cycle power plants and industrial applications
  • Hydroelectric turbines for hydroelectric power plants
  • Generators for all types of power plants
  • Boilers for thermal power plants
  • Condensers for thermal power plants
  • Reheaters for thermal power plants
  • Air preheaters for thermal power plants
  • Feedwater pumps for thermal power plants
  • Control systems for power plants
  • Maintenance and repair services for power plants

EMS Power Machines is committed to providing its customers with high-quality products and services. The company has a strong reputation for reliability and innovation. Power Machines is a leading provider of power equipment and services, and it plays a vital role in the global power industry.

EMS Power Machines, which began in 1961 as a small factory of electric motors, has become a leading global supplier of electronic products for different segments. The search for excellence has resulted in the diversification of the business, adding to the electric motors products which provide from power generation to more efficient means of use.

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