Shell and Tube Heat Exchanger basics explained

Summary

This video explains the workings of different types of heat exchangers, including shell and tube, double pipe, and hairpin designs. Shell and tube heat exchangers are used in applications like pharmaceutical factories and refrigeration, where two fluids exchange thermal energy through tubes surrounded by another fluid in the shell. The video also highlights how heat transfer is maximized with the use of baffles in the shell. The simpler double pipe heat exchanger and the more efficient hairpin type are also covered, with real-world examples from dairy processing and oil refineries, demonstrating their use in various industries.

Takeaways

• 😀 Shell and tube heat exchangers consist of a header, shell, and tubes that allow two different fluids to transfer heat through a tube wall.
• 😀 The header has inlets and outlets for one fluid, while the shell surrounds the tubes and provides inlets and outlets for the second fluid.
• 😀 Baffles inside the shell force the fluid to change direction, creating turbulence to maximize heat transfer.
• 😀 Tube ends are separated by a partition inside the header, enabling the fluid to flow through and around the tubes.
• 😀 In pharmaceutical applications, steam can flow through the shell while a chemical product flows through the tubes, transferring heat to the product.
• 😀 Shell and tube heat exchangers are also commonly used in refrigeration systems, where water absorbs heat from refrigerant and is cooled in a cooling tower.
• 😀 Double pipe heat exchangers use a tube within a shell where one fluid flows through the tube and another surrounds it, transferring heat through the tube wall.
• 😀 Tube in tube heat exchangers are simpler to manufacture and cost-effective, but may have wasted heat transfer around the bend areas.
• 😀 Hairpin type heat exchangers, often used in oil refineries, fully utilize the surface area of the bends for heat transfer and typically use multiple tubes for greater surface area.
• 😀 Double pipe and hairpin type heat exchangers are widely used in food processing and pharmaceutical production for applications such as dairy heating or mixing ingredients.

Q & A

What is a shell and tube heat exchanger?

A shell and tube heat exchanger is a type of heat exchanger that consists of tubes arranged within a shell. One fluid flows through the tubes, while another flows through the shell around the tubes, facilitating heat transfer between them.

What is the function of the header in a shell and tube heat exchanger?

The header serves as the inlet and outlet for one fluid, typically located at the ends of the heat exchanger. It connects the fluid to the tubes or shell, enabling the flow of fluid through the system.

How do baffles contribute to the heat exchange process in a shell and tube heat exchanger?

Baffles are metal sheets inside the shell that partially block the flow of fluid. They force the fluid to change direction multiple times, creating turbulence that enhances the heat transfer by ensuring thorough mixing of the fluid.

Can the components of a shell and tube heat exchanger be removed for maintenance?

Yes, both the header and the tubes can be removed for cleaning, repairs, and maintenance to ensure the heat exchanger continues to function efficiently.

What role does the partition in the header play in a shell and tube heat exchanger?

The partition, also known as the divider, separates the ends of the tubes within the header. This ensures that the fluids are directed properly, allowing one fluid to flow through the tubes and the other to flow through the shell.

Can you explain the heat transfer process in a shell and tube heat exchanger with an example?

In a pharmaceutical factory, steam from a boiler flows through the shell and surrounds the tubes. A chemical product flows through the tubes, absorbing heat from the steam through the tube walls. The steam condenses and returns to the boiler for reheating, repeating the cycle.

How do shell and tube heat exchangers function in refrigeration applications?

In refrigeration, such as in industrial chillers, the hot refrigerant flows through the shell, while water flows through the tubes. The water absorbs heat from the refrigerant, cooling it before the water is returned to the cooling tower to release the heat into the atmosphere.

What is the main difference between a shell and tube heat exchanger and a double pipe heat exchanger?

A double pipe heat exchanger consists of one pipe inside another, with one fluid flowing through the inner pipe and the other flowing through the outer shell. Unlike the shell and tube design, it does not have multiple tubes but uses a simple back-and-forth tube structure.

What is the advantage of using a hairpin heat exchanger?

A hairpin heat exchanger utilizes multiple tubes to maximize the surface area for heat transfer. This design improves heat exchange efficiency but also increases resistance to flow.

In what industries are double pipe heat exchangers commonly used?

Double pipe heat exchangers are commonly used in food processing and pharmaceutical production due to their simple design and ease of manufacturing.