heat exchanger manufacturer in INDIA

What is a shell and tube heat exchanger?



Introduction

United Heat Exchangers is a Leading shell and tube heat exchanger manufacturer and supplier in India, delivering reliable, high-performance heat transfer solutions. When it comes to heat transfer systems in industrial settings, shell and tube heat exchangers are a cornerstone technology. Whether you’re dealing with thermal management in manufacturing, oil refining, or chemical processes, these heat exchangers are renowned for their durability, efficiency, and versatility. 


What is a shell and tube heat exchanger?

A shell and tube heat exchanger (STHE) is a type of heat exchange device commonly used in industrial processes to transfer heat between two fluids. It consists of a series of tubes, with one fluid flowing inside the tubes and another fluid flowing outside the tubes but inside a larger shell. This setup allows for efficient heat transfer between the two fluids, as heat moves through the tube walls from the hotter fluid to the cooler one.

Definition and Function

The primary function of a shell and tube heat exchanger is to transfer heat between two fluids without mixing them. One fluid typically passes through the inner tubes, while the second fluid circulates around the outside of these tubes inside the shell. Heat from the hot fluid is transferred through the walls of the tubes to the cold fluid. This heat transfer is typically achieved through conduction and convection mechanisms.

Components

  1. Shell: The outer container that holds the tubes and allows the second fluid to flow over the outside of the tubes.
  2. Tubes: The inner pipes through which the first fluid (the one being heated or cooled) flows.
  3. Tube Sheets: These are plates that hold the tubes in place and seal the ends of the tubes to prevent leaks.
  4. Baffles: Placed inside the shell to direct the flow of the second fluid, ensuring that it flows across the tubes to increase heat transfer efficiency.
  5. End Caps: These seal the ends of the shell and tubes and may also direct the flow of the fluids.


The Working Principle of a Shell and Tube Heat Exchanger

  1. Heat Transfer Mechanism:

    • Conduction: Heat travels through the tube walls from the hotter fluid (shell-side) to the cooler fluid (tube-side).
    • Convection: As the fluids move, heat is carried away by the flow of the fluids. The convection heat transfer happens on both the tube side and shell side.

      • Factors Affecting Efficiency:

      • The surface area of the tubes.
      • The fluid velocities.
      • The properties of the fluids themselves, such as their thermal conductivity.

  2. Fluid Flow:

    • The fluid can flow either smoothly (laminar flow) or turbulently. Turbulent flow is preferred for better heat transfer since it mixes the fluid, enhancing heat exchange.
    • Design adjustments like tube counts and baffle configurations are made by engineers to optimize fluid velocity and turbulence, ensuring efficient heat transfer.

      • Hot and Cold Fluid Flow in Shell and Tube

      1. Hot Fluid: One fluid, usually at a higher temperature, is introduced into the tubes. The hot fluid may be steam, oil, or any other liquid or gas.
      2. Cold Fluid: The second fluid, which is cooler, flows around the tubes in the shell. This fluid could be water, air, or another coolant.

  3. Thermal Efficiency:

    • The goal is to transfer as much heat as possible without oversizing the exchanger, which would increase costs.
    • Factors Influencing Thermal Efficiency:
      • Exchanger design.
      • Temperature difference between the fluids.
      • Fluid properties.

  4. Outlet Nozzles:

    • After heat exchange, the fluids must exit the exchanger.
    • Tube-side fluid: In a multi-pass exchanger (like BEU type), the fluid may exit from the same end it entered. In a single-pass system (common in NEN or BEM TEMA types), the fluid exits from the opposite end.
    • Shell-side fluid: This typically exits at the top if it is being heated or at the bottom if it is being cooled, though it depends on the specific process design.

  5. Flow Arrangements:

    • Co-current flow: Both fluids flow in the same direction. This is less efficient compared to counterflow.
    • Counter flow: The fluids flow in opposite directions. This arrangement allows for a greater temperature gradient and, hence, better heat transfer.
    • Mixed Flow: Many exchangers use a mix of co-current and counterflow configurations, especially when the tube-side fluid has multiple passes.


Types of Shell and Tube Heat Exchangers

One-Pass Heat Exchangers

In a one-pass heat exchanger, the fluid flows in a single direction through the tubes, providing a simple yet effective method for heat exchange. When modest heat transfer is needed and space is at a premium, this design is frequently used.

Two-Pass Heat Exchangers

Two distinct passes for the fluid inside the tubes are a feature of two-pass heat exchangers. This arrangement increases the fluid’s contact time with the heat-exchanging surface, enhancing heat transfer efficiency compared to one-pass designs.

Four-Pass Heat Exchangers

Four-pass heat exchangers feature a design that divides the tube bundle into four separate passes for the fluid. This arrangement significantly improves heat transfer by increasing the path length of the fluid and introducing more turbulence.

Multi-Pass Custom Heat Exchangers

Multi-pass heat exchangers are tailored to meet specific thermal needs. These exchangers can have several passes, custom-designed based on the required heat exchange and space considerations. They are frequently employed in sectors requiring sophisticated heat transfer.

  1. U-Tube Heat Exchangers

    2. U tube heat exchangerStructure and Design
    • Tubes are fixed at a single tubesheet after being bent into a "U" form.
    • Allows free thermal expansion without stressing the materials.
    • No need for expansion joints.
    Pass Method
    • Typically two-pass: Fluid enters one end of the U-tube, makes a 180° turn, and exits from the same end.
    Pros:
    • Naturally accommodates thermal expansion.
    • More cost-effective due to simpler construction.
    • Saves space with a compact layout.

  2. Fixed Tube Sheet Exchangers

    3. Construction
    These exchangers have their tube bundles fixed permanently between two tube-sheets. The shell remains static, and the internal tubes are inaccessible from outside once installed.
    Ideal Use Cases
    This design is perfect for non-corrosive and clean fluids where thermal expansion isn’t a significant concern.
    Pass Method
    • One-pass, two-pass, four-pass, or even multi-pass configurations are possible by adding partition baffles at the heads.

  3. Floating Head Heat Exchangers

    4. Functionality
    In a floating head exchanger, one end of the tube bundle is free to move. This design helps manage thermal expansion and allows for easier disassembly.
    Maintenance Advantages
    • Easier to clean and inspect.
    • Ideal for fluids that may cause fouling.
    • Suitable for higher temperature variations.
    Pass Method
    • Supports multiple passes on the tube side, making it highly customizable for efficiency.

  4. Kettle-Type Heat Exchangers

    5. Kettle reboilerKey Applications
    Typically used for boiling applications, especially as reboilers in distillation systems.
    Design Features
    • Equipped with a vapor disengagement area.
    • Maintains liquid level with an internal weir.
    • Effective for phase changes like boiling or evaporation.
    Pass Method
    • Usually single-pass on the tube side.
    • Shell-side fluid evaporates as it absorbs heat.

  5. Hairpin Heat Exchangers

    6. Hairppin Heat ExchangerCompact and Efficient
    These are U-shaped, double-pipe exchangers housed in a compact shell, offering high thermal performance in a small footprint.
    Common Industries
    Commonly used in the oil and gas sector, power plants, and chemical industries where space savings and efficiency are priorities.
    Pass Method
    • Normally two-pass, with potential for multi-pass depending on shell design.

  6. Double Tube Sheet Heat Exchangers

    7. For Hazardous Fluids
    When handling toxic or reactive substances, these exchangers offer an extra layer of safety.
    Leak Prevention Design
    Any leak between the shell and tube fluids will be visible in the gap between the two sheets, preventing cross-contamination and improving safety.
    Pass Method
    • Available in one-pass and multi-pass configurations.

  7. Split-Flow and Divided-Flow Designs

    8. Enhanced Heat Transfer
    Split-flow exchangers divide the shell-side fluid, improving flow distribution and heat transfer efficiency.
    Thermal Stress Management
    Divided flow configurations help balance temperature gradients and minimize stress on the exchanger components.
    Pass Method
    • usually combined with split or divided flow on the shell side and multi-pass on the tube side.


Comparison Table: Heat Exchanger Types vs Flow Pass Options

Heat Exchanger Types

Heat Exchanger Types Comparison

Heat Exchanger TypeCommon Pass OptionsKey AdvantagesTypical Uses
U-TubeTwo-PassCompact, thermal expansion friendlyHVAC, moderate industrial use
Fixed Tube SheetOne, Two, Four, Multi-PassSimple, cost-effectiveClean process fluids
Floating HeadMulti-PassEasy maintenance, high-temp usePetrochemical, Power
Kettle TypeSingle-PassIdeal for phase changeReboilers, evaporators
HairpinTwo-Pass, Multi-PassSpace-saving, high efficiencyOffshore, modular setups
Double Tube SheetOne, Multi-PassSafe for hazardous fluidsPharma, food, toxic chemicals
Split/Divided FlowMulti-PassHigh performance, low pressure dropHigh-end industrial applications


Materials & Construction of Shell and Tube Heat Exchangers

When it comes to shell and tube heat exchangers, the materials used and the construction methods play a crucial role in their overall efficiency, durability, and performance in industrial applications. The selection of appropriate materials ensures that the heat exchanger can withstand extreme conditions like high temperatures, corrosive fluids, and high pressure while maintaining optimal heat transfer.

  1. Materials Used in Shell and Tube Heat Exchangers

    2. The materials chosen for both the shell and the tubes must be able to handle various operating conditions, including temperature extremes, corrosive substances, and high pressure. The following materials are most frequently used to build shell and tube heat exchangers:
    • Carbon Steel
      • Carbon steel is commonly used for applications where the fluid being handled is not highly corrosive. It offers a good balance between strength, cost, and performance. Carbon steel is often used for non-corrosive fluids, such as water or air, and is favored for applications where cost efficiency is critical.
    • Stainless Steel
      • Stainless steel is widely used in shell and tube heat exchangers due to its corrosion resistance, particularly when handling aggressive fluids. The addition of chromium makes stainless steel resistant to rust, oxidation, and other types of corrosion, making it ideal for use in industries like food and beverage, pharmaceuticals, and petrochemicals. Common grades include 304, 316, and 317 stainless steel, with 316 being more resistant to corrosion, especially in chlorides.
    • Titanium
      • Titanium is chosen for its superior corrosion resistance, especially when exposed to seawater, acids, or other harsh chemicals. This makes it an excellent choice for the oil and gas industry, marine applications, and other highly corrosive environments. However, titanium is typically more expensive than stainless steel, making it suitable for specialized applications.
    • Copper and Copper Alloys
      • Copper is often used in applications that require efficient thermal conductivity, especially in smaller heat exchangers. Copper alloys, such as brass and bronze, are used for their improved mechanical properties and resistance to corrosion. These materials are often employed in heat exchangers for HVAC systems, refrigeration, and water cooling.
    • Alloy Steels
      • Usually, alloy steels are utilized when high temperatures and high pressures are needed. These materials are strengthened, hardened, and resistant to heat stress by the addition of different alloying elements such as nickel, chromium, and molybdenum. The petrochemical, electricity generation, and chemical processing sectors all make extensive use of them.
    • Nickel Alloys
      • Nickel alloys, such as Inconel or Hastelloy, are highly resistant to corrosion and can withstand extremely high temperatures. These materials are used in applications where both temperature and corrosion resistance are critical, such as in chemical and petrochemical processes, nuclear power plants, and high-temperature heat exchangers.
    • Polymeric Materials
      • In some cases, polymeric materials such as PTFE (polytetrafluoroethylene) and PEEK (polyetheretherketone) are used for specialized applications. These materials offer excellent resistance to aggressive chemicals and are suitable for applications involving highly corrosive fluids at relatively lower temperatures.

  2. Construction of Shell and Tube Heat Exchangers

    3. The construction of a shell and tube heat exchanger involves several key components that are designed to work together for efficient heat transfer and fluid flow. Below are the critical elements involved in the construction process: parts of shell and tube
    1. Shell
      2. The shell is the outer casing that houses the tubes and contains the fluid that exchanges heat with the fluid inside the tubes. It is generally made from materials like carbon steel or stainless steel, depending on the application. The size and design of the shell are tailored to accommodate the number and type of tubes, as well as the fluid flow rates and pressure requirements.
    2. Tubes
      3. Tubes are the internal components where heat transfer occurs. They are typically made of metal, such as stainless steel, copper, or alloys, based on the application. Tubes can be either straight or bent, and in some cases, they may feature finned surfaces to increase the surface area for heat transfer.
    3. Straight Tubes
      4. Often used in applications where the fluid flow is simpler and less demanding in terms of temperature and pressure.
    4. U-Tube Tubes
      5. These tubes are bent into a U-shape to accommodate thermal expansion and contraction. U-tube heat exchangers are commonly used in high-temperature applications.
    5. Tube Sheets
      6. Tube sheets are the plates that hold the tubes in place within the shell. In order to secure the tubes and guarantee a leak-proof seal between the tubes and the shell, certain parts are essential. The tube sheets are typically welded or bolted to the shell and designed to withstand the internal pressures and stresses of the heat exchanger.
    6. Baffles
      7. The shell-side fluid's passage over the tubes is guided by baffles. These components help improve heat transfer by creating turbulence in the fluid, which enhances the heat exchange process. The baffles also ensure that the fluid flows across the tubes in an optimized pattern, increasing the overall efficiency of the heat exchanger.
    7. End Caps
      8. End caps cover the ends of the tubes and seal off the system. They are critical for containing the fluids and preventing leaks. End caps are usually welded or bolted to the tube sheets and designed to be easily removable for maintenance and cleaning.
    8. Supports and Mounting
      9. The structure of the heat exchanger includes supports and mounting brackets that hold the system in place during operation. These components are essential for ensuring that the heat exchanger remains stable and functional under extreme conditions of temperature, pressure, and flow.
    9. Gaskets and Seals
      10. Gaskets and seals are used between the tube sheets and end caps to prevent leakage of the fluids. These components are made from materials that can withstand high pressures and temperatures, such as rubber, PTFE, or other specialized materials.
    10. Inspection and Maintenance Features
      11. A well-designed shell and tube heat exchanger incorporates features that allow for easy inspection, cleaning, and maintenance. This includes access points such as manholes, removable end caps, and the ability to replace or repair individual tubes without disassembling the entire system.

  3. Construction Techniques

    4. The construction of shell and tube heat exchangers involves several techniques to ensure the structural integrity and performance of the system:
    • Welding
      • Welding is the primary method used to join the various components of the heat exchanger. The tubes are welded to the tube sheets, and the end caps are welded to the shell. Specialized welding techniques are used depending on the material and design, such as TIG (tungsten inert gas) welding for stainless steel or MIG (metal inert gas) welding for carbon steel.
    • Brazing
      • For certain applications, brazing may be used to join materials, particularly in situations where the materials must resist high temperatures and pressures but where welding is impractical or too costly.
    • Bolting
      • In some cases, the end caps and other parts of the heat exchanger are bolted together to facilitate easier disassembly and maintenance. Bolted connections are typically used in combination with gaskets to prevent leaks.
    • Tube Expansion
      • To ensure that the tubes are securely fastened into the tube sheets throughout the production process, they are frequently enlarged at the ends. This ensures a tight seal and efficient heat transfer between the tube and the shell-side fluid.
    • Hydrostatic Testing
      • Once the heat exchanger is assembled, it is subjected to hydrostatic testing to ensure that there are no leaks. The heat exchanger is filled with water or another fluid and pressurized to check for any signs of leakage, ensuring that the system is fully functional and safe.


Key Characteristics of Shell and Tube Heat Exchangers

shell tube heat exchanger

  • Heat Transfer Capacity and Flow Rate
    • Shell and tube heat exchangers are designed for high heat transfer efficiency. They can handle significant flow rates, making them ideal for large-scale applications like power plants, chemical processing, and HVAC systems.
  • Temperature and Pressure Capabilities
    • These heat exchangers are known for their ability to operate under extreme temperatures and pressures, making them suitable for applications such as oil and gas refineries, petrochemical industries, and food processing.
  • Power Consumption
    • Shell and tube heat exchangers are engineered to maximize heat transfer with minimal power consumption, contributing to cost savings and enhanced operational efficiency.
  • Cost Minimization
    • The robust design and high efficiency lead to reduced operational costs and lower maintenance expenses, offering a cost-effective solution in the long run.
  • CO2 Emissions Control
    • By optimizing the heat transfer process, shell and tube heat exchangers help reduce the energy consumption of industrial processes, thereby contributing to CO₂ emissions control and environmental sustainability.


    Features of Our Shell and Tube Heat Exchangers

    At United Heat Exchangers, we take pride in offering the highest quality shell and tube heat exchangers. Our products feature:

    • High Heat Transfer Efficiency: Designed to meet the demands of high-performance industrial environments.
    • Customization: Tailored to fit your specific industry and application needs.
    • Durability: Long-lasting performance is guaranteed by its construction, which can tolerate high temperatures and pressures.
    • Ease of Maintenance: Designed for easy inspection and maintenance to minimize downtime.


    Additional Features of Our Heat Exchangers

    • Corrosion Resistance: Our heat exchangers are made from high-quality materials to ensure resistance to corrosion and erosion, especially in harsh environments.
    • Enhanced Surface Area: With features like finned tubes and optimized tube arrangement, our heat exchangers offer increased surface area for heat transfer.
    • Leak Prevention: Designed with leak-proof mechanisms to ensure fluid containment and safety.


    Industrial Uses of Shell and Tube Heat Exchangers

    Shell and tube heat exchangers are essential in various industries:

    • Chemical Processing: Used to manage high temperatures and pressures in reactors.
    • Oil and Gas: vital for heat exchange in gas processing and oil refineries.
    • Power Generation: Integral in nuclear, thermal, and hydroelectric plants for managing heat transfer.
    • HVAC: helps in controlling the heating and cooling systems of big buildings and industries.
    • Food and Beverage: Utilized in pasteurization and heat treatment processes.
    • Pharmaceuticals: Ensures safe and efficient temperature control in drug production.


    Benefits You’ll Experience with Our Shell and Tube Heat Exchangers

    By choosing United Heat Exchangers, you gain access to a range of benefits:

    1. Superior Heat Transfer Efficiency
      2. Our shell and tube heat exchangers maximize heat transfer, leading to energy savings and enhanced system performance.
    2. Cost Efficiency
      3. We provide solutions that lower operational and maintenance costs, giving you the best return on investment.
    3. Environmental Impact
      4. Our heat exchangers are designed to reduce energy consumption, minimizing your carbon footprint and complying with environmental regulations.
    4. Customization and Flexibility
      5. With our tailored solutions, you get a system that perfectly fits your industrial needs, whether it’s for high-pressure, high-temperature, or space-constrained applications.
    5. Long-Term Durability
      6. Built to last, our heat exchangers are resistant to wear and tear, ensuring long-term reliability.

    Why United Heat Exchangers?

    At United Heat Exchangers, we are committed to delivering only the highest quality heat exchange systems. Here’s why our products stand out:
    • Expertise: With years of experience in designing and manufacturing shell and tube heat exchangers, we offer expert solutions tailored to your specific needs.
    • Quality: Our heat exchangers are built to last, offering unmatched durability, performance, and efficiency.
    • Customer Satisfaction: We pride ourselves on providing exceptional customer service and ensuring that our solutions meet your exact specifications.


    Shell and Tube Heat Exchanger Certifications We Have

    ASME Certifications

    • ASME Certification (General)
    • ASME U Stamp Certificate – UNIT I
    • ASME U Stamp Certificate – UNIT II
      • includes pressure vessels made in accordance with ASME Section VIII, Div 1.
    • ASME U2 Stamp Certificate – UNIT I
      • Applicable for high-pressure designs under ASME Section VIII, Div. 2
    • R Stamp Certificate
      • Authorized to perform repairs and alterations of pressure-retaining items
    • NB (National Board) Stamp Certificate
      • Registration and certification with the National Board of Pressure Vessel and Boiler Inspectors

    ISO Certifications

    • ISO 9001:2015 – UNIT I and UNIT II
      • Quality Management System
    • ISO 14001:2015 – UNIT I and UNIT II
      • Environmental Management System
    • ISO 45001:2018 – UNIT I and UNIT II
      • Occupational Health & Safety Management System

    EIL (Engineers India Limited) Approvals

    • EIL Certificate – UNIT I
    • EIL Certificate – UNIT II
      • Approved supplier for engineering, oil & gas, and infrastructure projects

    Industry-Specific Certifications

    • American Petroleum Institute Certification
      • Typically API 660, for shell and tube exchangers used in petroleum refining

    Regulatory Certifications

    • Indian Boiler Regulations (IBR)
      • Mandatory for boilers and pressure vessels in India

    MSME ZED (Zero Defect Zero Effect) Certifications

    • ZED Gold MSME Certificate
      • For manufacturing excellence and sustainability
    • ZED Silver MSME Certificate
      • Recognizing quality and eco-friendly production for MSMEs


    Contact Us

    Ready to enhance your industrial processes with a reliable and efficient shell and tube heat exchanger? Contact United Heat Exchangers today to learn more about our products and services. Our knowledgeable staff is available to help you with the installation, maintenance, and selection procedures.


    Conclusion

    In conclusion, shell and tube heat exchangers are essential components in many industries, offering high efficiency, versatility, and cost-effectiveness. With United Heat Exchangers, you can trust that you’re getting a high-quality, customized solution that will enhance your system’s performance, reduce energy costs, and promote sustainability. Whether you're in chemical processing, power generation, or HVAC, our shell and tube heat exchangers are designed to meet the specific needs of your industry.


    Frequently Asked Questions (FAQs)

    1. What is a shell and tube heat exchanger?

      A shell and tube heat exchanger is a mechanical device used to transfer heat between two fluids. It is made up of a greater cylindrical shell that encloses a group of tubes (the tube bundle). One fluid flows through the tubes, while the other circulates around the tubes inside the shell. The heat is exchanged across the tube walls, typically through conduction and convection, without the fluids ever mixing.

    2. What are the key components?

      • Shell—outer casing
      • Tubes—carry one fluid
      • Tube Sheets—hold tubes
      • Baffles—direct fluid flow
      • End Caps—seal the system

    3. What are the flow pass options?

      • One-Pass—fluid flows once
      • Two-Pass/Four-Pass—fluid reverses direction
      • Multi-Pass—custom paths for enhanced transfer

    4. What are the common types?

      • U-Tube—compact, flexible
      • Fixed Tube Sheet—simple, cost-effective
      • Floating Head—easy to clean
      • Kettle Type—ideal for boiling
      • Hairpin—efficient, compact
      • Double Tube Sheet—for hazardous fluids
      • Split Flow—high performance

    5. What materials are used?

      • Carbon Steel—budget-friendly
      • Stainless Steel—corrosion-resistant
      • Titanium/Nickel Alloys—harsh chemicals
      • Copper Alloys—high conductivity
      • Polymerics—for aggressive fluids

    6. Which certifications are needed?

      • ASME U/U2/R/NB
      • ISO 9001, 14001, 45001
      • API 660, IBR
      • EIL Approved, ZED Gold/Silver

    7. What industries use them?

      8. Oil & gas, chemical, power, HVAC, food processing, and pharmaceuticals.

    8. What are the maintenance benefits of floating head types?

      9. They’re easy to clean, handle fouling fluids, and allow full bundle removal.

    9. How do they save energy?

      10. Efficient design reduces energy use and lowers CO₂ emissions.

    10. Why choose United Heat Exchangers?

      11. Certified, durable, high-efficiency systems with expert customization and support.