Shell and Tube Heat Exchangers: Types | Design | Selection
Shell and tube type heat exchanger is most commonly used equipment for heat transfer. Nowadays a variety of the heat exchangers are available and these are used as per its application and according to the service.
Within this article we will cover the types of the heat exchangers for Shell and tube. That is I tubes, U Tube, Kettles type and others. These are also divided according to the multiple passes and heat transfer coefficients. Now we will try to understand about the exchanger in the details below.
This type of exchanger is a combination of Shell and tubes in which multiple tubes are used for heat transfer and increase the contact surface area for heat transfer.
Shell and Tube Heat Exchangers parts list cover plat buffel tubes dome
Types of Shell and Tube Heat Exchangers
Shell and tube types of heat exchangers or classified depends on many criteria like number of passes and tube arrangement, below we have discribe some of them.
- U-Tube Heat Exchangers:
- Multi-Pass Heat Exchangers:
- Floating Head Heat Exchangers
- Fixed Tube Sheet Heat Exchangers
- Double Tube Sheet Heat Exchangers
U-Tube Heat Exchangers:
U Tube heat exchanger is the simplest and most common type of exchange. The fluid flows within it in a single way. That is best suitable for where thermal efficiency is not a crucial factor. This type of exchanger is generally used for HVAC systems and other low pressure applications. And where the pressure also drops is not a crucial factor.
Fixed Tube Sheet Heat Exchangers:
Fixed tube heat exchanger is also most commonly used in the chemical and oil and Gas Industries. The tube sheet is used to divide the shell and tube fluid mixing. Tubes fixed in tube sheets through a welding. This is best suited for temperature differences that are not an important factor between two floor fluids.
Floating Head Heat Exchangers:
The floating head types of heat exchangers used in oil and gas and petrochemicals Industries where the high temperature and high pressure application are required. Because due to the high temperature the floating head is expanded accordingly and adjusts itself without damaging any other internal parts.
The most benefit of this type of exchanger is that it is easy to maintain. This is used where the maintenance frequency of the equipment is very long. if in future requirement of the bundle removal for maintenance purpose you can do very easily do as compared to others.
Double Tube Sheet Heat Exchangers:
This type of heat exchanger is most commonly used in the pharmaceutical industries where the fluid mixing to each other is a very crucial factor. That can impact the process of the plant. In the Double tube heat exchanger there are two seats provided which prevent the mixing of liquid to other liquid and act as a barrier between both.
Multi-Pass Heat Exchangers:
The multi pass heat exchanger used for the high heat transfer coefficient but created more pressure drop. This is used for where high heat transfer is required in this type of heat exchange the fluid is rotated or circulates within the exchanger in multiple Times according to its passes.
Due to its circulation in the same exchanger the pressure drop also will increase and this type of exchanger is generally used for oil and gas, petrochemicals and power plants.
There are also some other types of shell and tube types heat exchanger available in the market types. Each heat exchange has some advantages and disadvantages. During selection it is important to consider your requirements like installation, capex, capacity, and criticality.
Design Considerations for Shell and Tube Heat Exchangers
The design condsiderationfacetor is the most important factor for appropriate selection of any type of equipment either pump or heat exchanger. This is equally important for both because heat exchangers are the heart of any plant and industry.
So during selection of the heat exchanger following factors need to be considered.
- Material Selection
- Heat Transfer Area
- Tube Diameter and Thickness
- Baffles and Pass Partition Plates
- Shell Diameter and Shell Side Flow
Material Selection:
Several factors also take care during materials selection, Because materials of any equipment directly impact on the life of that equipment.
Choose as per compatibility of the fluide with selected materials, resistant to corrosion of the selected materials for both tube and shell.
Some common types of materials used in construction of heat exchangers are stainless and carbon steel, copper, and titanium.
Heat Transfer Area
The heat transfer area is a key factor which can help the determining of efficiency of that exchanger, as we increase the surface area of the contact fluide, the efficiency is also increased accordingly. So that the proper sizing of tube lenght and numbers of tubes is very important during the selection.
Tube Diameter and Thickness
The tube’s diameter and thickness is also a direct impact on the eficiency of the exchanger because if we increase the thickness of the tube, the heat transfer is also impacted and reduced.
If selected, a small bore tube increases the pressure drop in the equipment and on the other hand a big bore diameter tube reduces pressure drop but the heat transfer will be compromised.
So during the selection must be considered and optimized for both factors. As per specific application requirements.
Shell Diameter and Shell Side Flow:
The shell diameter impacts on the fluid velocity and pressure drop due to available space for flow. if the space between exchanger and tubes are less increase the pressure drop and impact on fluide velocity.
These factors are also impacted by the flow pattern, some heat exchangers have parallel flow and some have cross flow.
So select as per appropriate requirements based on the specific application requirements.
Baffles and Pass Partition Plates
A baffle plate and pass partition are also very important for reducing pressure drop and increasing heat transfer. baffle plates increase heat transfer rate and the partition plates are used to increase the heat transfer efficiency.
It is used for specific requirements to increase the fluid flow turbulance and the multiple pass improves the better control of flow and heat transfer. The selection and position of both is very important and that is also selected on the basis of fluid nature and properties.
Selection Criteria for Shell and Tube Heat Exchangers
Selecting the right shell and tube heat exchanger for a specific application requires careful consideration of various factors. The following selection criteria will help you make informed decisions and ensure optimal performance and efficiency:
- Fluid Properties
- Space Constraints
- Cost Considerations
- Maintenance Requirements
- Longevity and Reliability
- Heat Transfer Requirements
By considering these selection criteria, you can ensure that the shell and tube heat exchanger chosen for your application meets the specific requirements and provides optimal heat transfer performance. In the next section, let’s discuss the advantages and disadvantages of shell and tube heat exchangers.
Advantages and Disadvantages of Shell and Tube Heat Exchangers
Shell and tube heat exchangers offer numerous advantages, making them a popular choice for various industrial applications. However, like any other heat exchanger type, they also have certain disadvantages. Let’s explore the advantages and disadvantages of shell and tube heat exchangers:
Advantages:
- Easy Maintenance is easy and simple.
- Scalability – It can be scale up and down as per requirement.
- High Heat transfer Efficiency because of the large surface area.
- Durability: Long life due to low maintenance if efficiently designed.
- Versatility is due its feature of high heat and high pressure application and it is also used for liquid to liquide and liquide to gas application.
Disadvantages:
- Large Footprint: Large area required for installation and maintenance purpose.
- Higher Capital Cost: Costly due its material and safety factor and application.
- Potential Fouling Issues easily found due to its tube bore is small and maintenance frequency is also long.
- Limited Heat Recovery: Heat transfer and recovery is limited due to its designs being fixed and can not be extended as compared to plate type heat exchanger.
Common Applications of Shell and Tube Heat Exchangers
There are multiple application of this type of heat exchanger, these are as below
- Oil and Gas Industry:
- Chemical Processing:
- Power Plants
- HVAC Systems
- Pharmaceutical Industry
Heat Exchanger Design download sheet Click the link
Maintenance and Troubleshooting Tips for Shell and Tube Heat Exchangers
To improve the efficiency and life regulate maintenance and inspection is most common to avoid any types of failuer.
Maintenance Marvels:
- Gasket Guardians: Regularly inspect and replace gaskets to ensure a proper seal and prevent leaks.
- Routine Checkups generate a checklist for inspection to prevent corrosion and fouling in and on the tubes.
- Cleaning Champions, Fix the cleaning time schedule to remove scaling and fouling and maintain the optimum efficiency.
- Temperature Tamers: Check, record and review the inlet and outlet temperatures of both fluids on a daily basis. For cleaning signals.
