How does a plate heat exchanger work
Heat transfer theory
- Heat is always transferred from a hot medium to a cold medium.
- There must always be a temperature difference between the mediums.
- The heat lost from the hot medium is equal to the amount of heat gained by the cold medium.
About heat exchanger
A heat exchanger is a piece of equipment that transfers heat from one medium to another.
There are two main types of heat exchanger:
- Direct heat exchange, where both mediums are in direct contact with each other. Eg - A cooling tower where water cools through direct contact with air.
- Indirect heat exchange though divided media.
What is a plate heat exchanger
- gasketed plate-and-frame type heat exchangers
- Industrial line range
- semi welded industrial line-typed plate heat exchanger
- Welded plate-and-block heat exchangers e.g. Alfa Laval Compabloc
- Welded plate-and-shell heat exchangers e.g. Alfa Laval DuroShell and Packinox
- Welded spiral heat exchangers
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How gasketed plate heat exchanger works
Advantages of plate heat exchanger:
- Heat transfer precision – improved temperature approach, true counter-current flow, 80-90% less hold-up volume.
- Low cost - low capital investment, installation costs, limited maintenance and operating costs.
- Greatest reliability - less fouling, stress, wear, and corrosion.
- Responsible - least energy consumption for most process effect, reduced cleaning.
- Easy to expand capacity – adjustable plates on existing frames.
Disadvantages of plate heat exchangers:
- Poor sealing would case leakage occurrence which will be a replacement hassle.
- Limited pressure use, generally not more than 1.5MPa.
- Limited operating temperature due to temperature resistance of the gasket material.
- Small flow path, and not suited for gas-to-gas heat exchange or steam condensation.
- High blockage occurrence especially with suspended solids in fluids.
- The flow resistance is larger than the shell and tube.
Maintaining and service for your gasketed plate heat exchanger
Here are the two most common types of services.
Troubleshooting a plate heat exchanger, if the following occurs:
- A decrease in performance
- Unexplainable deviations from the temperature programme or operation requirements
- External or internal leakages
- Disturbances in the process
- Need for increased capacity
- High energy consumption
Reconditioning of plate heat exchanger:
- When high thermal performance is vital to the process.
- For 100% reliability to prolong the heat exchanger lifetime.
- To restore performance should foul, corrosion or leakage occurs.