Reheater in boiler

Market Dynamics of Reheaters in Boiler Systems

Market Overview: The global market for industrial boilers, which includes reheaters, was valued at approximately US$20.5 billion in 2023 and is projected to grow to US$28.8 billion by 2030, reflecting a compound annual growth rate (CAGR) of 5.0% during this period, according to Global Industry Analysts, Inc. In particular, the fire-tube boiler segment is expected to significantly contribute to this growth, reaching US$17.9 billion by 2030 with a CAGR of 5.5%. This upward trend indicates a robust demand for reheater technologies that optimize thermal efficiency and overall system performance. The U.S. and China emerge as key markets, with the U.S. market estimated at US$5.5 billion in 2023, while China is anticipated to grow at a 4.7% CAGR, reaching US$4.5 billion by 2030.

Industry Insights: As industries seek to enhance energy efficiency and reduce operational costs, the adoption of reheater systems in boiler setups is becoming increasingly prevalent. This shift is driven by the growing emphasis on sustainability and the need for process optimization across various sectors. Major players in the boiler market are innovating to meet these demands, focusing on advanced materials and control technologies that improve heat recovery. Furthermore, consumer behavior is shifting towards integrated solutions that combine reheating capabilities with automation and monitoring systems. Distribution channels are also evolving, with a notable increase in online platforms like Alibaba.com facilitating global transactions and interactions between suppliers and buyers. This trend highlights the importance of digital transformation in the boiler industry, paving the way for more efficient purchasing processes and broader market access.

Types of reheater in boiler

Reheaters are secondary heating components in a steam boiler that are generally made of a series of pipes that are laid in the radiant heat exchange section of a boiler. The main function of reheaters in boilers is to ensure that the steam temperature supplied to the turbine remains constant throughout the process. The turbine operates in an optimal range due to consistent steam temperatures, enhancing its efficiency. The reheater's role goes beyond maintaining steam temperature; it also plays a vital role in preventing cylinder damage within the turbine.

Depending upon the operating conditions and requirements, several kinds of reheater types are available:

• Superheating: It increases the temperature of saturated steam (water vapor) beyond the boiling point. Superheating steam is crucial in preventing turbine blade corrosion and improving efficiency. In a superheated steam boiler, water is converted into steam by adding heat, resulting in superheated steam.
• Radiant reheater: Radiant reheaters are primarily used in high-temperature and pressure applications, such as fossil-fuel boilers. They are usually located directly above the furnace, where radiant heat from burning fuel heats the superheated water/steam. The combination of furnace radiant heat and reheater proximity makes radiant reheaters highly efficient at converting residual moisture in the steam back into superheated steam.
• Convective reheater: Convective reheaters rely on heat transferred from hot gases moving across tube surfaces by convection. Turbine back pressure, moisture content in steam, flue gas temperature, and other factors influence the location of convective reheaters in the boiler unit. They are found in units with high turbine back pressure, which increases the moisture content in the steam. Nevertheless, convective reheaters are less efficient than radiant reheaters because they depend solely on flue gas temperature for heat transfer.
• Superheater and reheater combined: This type of reheater combines both a superheating and reheating section into one unit. It provides added flexibility in boiler design and operation by allowing the adjustment of the proportions of superheated and reheated steam according to specific needs or preferences.

These are a few boiler reheater variations that play an important part in increasing the efficiency and performance of steam turbines by providing consistent superheated steam. Their significance will continue to grow as industries strive to optimize energy use and reduce environmental impact.

Specification and maintenance of reheater in boiler

Specifications of reheater boilers may differ according to the boiler and the performance requirements. Some common specifications include the operating pressure, which typically ranges between 0.25 to 5.4 MPa.

Operating temperatures may range between 400 degrees Celsius and 540 degrees Celsius. The reheater capacity is usually specified in the mass flow rate of steam per unit of time. Dimensions of reheater boilers are usually available upon request.

Generally, reheater boilers are built to be sturdy and durable, yet they require regular maintenance, inspection, and repair to prevent premature failure and ensure the reliability of the boiler. Some routine maintenance tips include the following:

• Users should establish a periodic inspection and maintenance schedule for the reheater based on the manufacturer's recommendations and also consider the boiler's operating conditions. Regular monitoring of the reheater's performance is crucial, including its operating pressure, temperature, and steam quality. Any deviations from the normal parameters should be investigated promptly to identify the cause and prevent potential issues.
• All components of the reheater boiler should be clean and free from any obstructions. Water treatment is also essential to prevent scale buildup and corrosion in the reheater. Users should also ensure that the water used in the boiler is of the appropriate quality and that effective water treatment programs are implemented.
• Upon inspection, users should identify any signs of wear, damage, or leakage in the reheater's components, such as the reheater tubes, headers, and insulation. If any issues are detected, they should be addressed promptly to prevent further damage.
• Users should keep records of the maintenance activities and inspections performed on the reheater boiler. This documentation can help track the reh- reater's performance and identify potential trends or recurring issues that may require further investigation or additional maintenance.

Usage scenarios of reheater in boiler

Reheaters are essential components of high-pressure, high-temperature steam plants. The primary purpose of reheaters in boilers is to increase the temperature of the steam generated by the boiler before feeding it to the final stages of the turbine. This helps to improve the efficiency of the cycle and increase the output of the plant. Besides, reheated steam is also drier, which results lessening the adverse effects of steam carrying water droplets on turbine blades.

The use of reheaters extends beyond just improving thermal efficiency. It also contributes to environmental sustainability by reducing CO2 emissions per unit of electricity generated. As utilities strive to maximize output while minimizing emissions, the role of reheaters in enhancing both turbine performance and eco-friendliness cannot be overstated.

Superheaters and reheater boiler are commonly used in the following industries:

• Power Generation:

  Reheater boilers are widely used in power generation plants, especially in the production of electricity from fossil fuels such as coal, oil, and natural gas. These plants often employ steam turbines for electricity generation, and reheater boilers play a crucial role in enhancing the efficiency of the steam cycle. The efficient conversion of fuel into high-temperature steam by reheater boilers contributes to the overall efficiency of power generation from fossil fuel plants.

• Oil Refineries:

  Oil refineries utilize reheater boilers as a vital component of their operations. The high-temperature steam produced by reheater boilers is indispensable for various processes within the refinery, including cracking, distillation, and dehydration. These processes are essential for transforming crude oil into valuable petroleum products such as gasoline, diesel, and jet fuel. The efficiency and reliability of reheater boilers are paramount in ensuring the smooth functioning of oil refineries and the production of high-quality refined products.

• Chemical Manufacturing:

  Reheater boilers play a significant role in the chemical manufacturing industry by providing the high-pressure, high-temperature steam needed for numerous chemical processes. This includes the production of chemicals, polymers, and other specialized materials used in various applications. The steam generated by reheater boilers serves as a vital feedstock for chemical reactions and processes, contributing to the production of essential chemicals and materials used in everyday products.

• Cellulose Ethanol Plants:

  In the production of cellulose ethanol, reheater boilers are instrumental in providing the necessary high-pressure, high-temperature steam. This steam is utilized to decompose lignocellulosic biomass, which serves as the primary feedstock for cellulose ethanol production. Lignocellulosic biomass can include materials such as agricultural residues, wood chips, and dedicated energy crops. The steam produced by reheater boilers aids in the breakdown of the complex chemical structure of lignocellulosic biomass, releasing fermentable sugars that are subsequently converted into ethanol. Cellulose ethanol is an advanced biofuel that can be used as a renewable energy source for transportation and other applications. The role of reheater boilers in cellulose ethanol plants highlights their contribution to sustainable energy production and the reduction of dependence on fossil fuels.

How to Choose Reheater in Boilers

Choosing a reheater for boiler systems mainly involves looking at how boilers are designed and what needs to be achieved. Clients will want to ensure that the reheater they select can handle the weight of materials it is going to process, and also meet the temperature levels and pressure that have been established.

The type of boiler reheater to use will depend on the fuel being used to generate energy. For example, wood biomass requires a different type of reheater than natural gas. The physical set-up of the boiler system will also determine what kinds of reheaters are suitable. If the system is vertical, typically vertical tube reheaters are used, while horizontal systems use the tube bundle or serpentine configuration.

Another crucial aspect that clients must pay attention to is the material used for the reheater. It is usually carbon steel, stainless steel, or alloy steel. Depending on the corrosive nature of the system, one may need to choose stainless steel or alloys with robust corrosion resistance properties.

The efficiency and effectiveness of the reheater should also be studied and compared before purchasing. Many manufacturers will provide data and charts showing the efficiency of different kinds of reheaters. The more efficient the reheater is at utilizing heat or at transferring heat to the feed water, the more energy and cost savings for the overall facility.

Lastly, the maintenance requirements of the reheater should be assessed. Manufacturers will suggest maintenance schedules and requirements that need to be adhered to for ensuring longevity and effective functioning. If the boiler facility is far away from a city or urban area, then it would make sense to choose a reheater that has low maintenance requirements and is easy to maintain.

Reheater in boiler Q&A

Q1. Why are reheaters needed in boilers?

A reheater is vital for improving the overall efficiency of a boiler by ensuring that fuel is completely combusted and that the heat transmission to the water, thus generating high-quality steam, is maximized. The second advantage of reheaters is that they help regulate the temperature of steam entering the turbine to avoid damage and ensure smooth operation.

Q2. What are the main types of boiler reheaters?

A1. SuperReheaters: They increase the temperature of steam after it has been partially expanded in the turbine. They can be found in various boilers, including water tube and fire tube boilers. A super reheater might be a separate unit or an integral part of the boiler.
A2. Economiser Reheaters: Economisers are devices that recover the heat from the flue gases to preheat the feed water before it enters the boiler. Economiser reheaters aim to increase the overall efficiency of the system by recovering heat that would otherwise be lost.
A3. Combined Reheaters: Some boilers may incorporate combined reheaters that function as both super reheaters and economiser reheaters. These units are more complex but can offer higher efficiencies by utilising heat from multiple sources.

Q3. What materials are generally used for reheater pipes?

The materials used for reheater pipes in boilers may vary depending on the specific application, but some common options include:
Alloy steels are often used because of their combination of strength, resistance to heat, and anti-corrosion properties.
Stainless steels are known for their resistance to rust and corrosion.
Nickel alloys offer superior resistance to high temperatures and corrosion, especially in harsh environments.

Q4. What are the trends in boiler reheater technology?

More efficient heating preservation and transfer techniques are being developed in reheaters, which will allow for the future use of higher pressures and temperatures. In addition, reheater designs will be made simpler because of modularity, which will ease assembly and cut costs. This will make industrial boilers more economically viable. Other innovations will include corrosion monitoring and resistance management systems.