Part 2: The basics of Shell and Tube Heat Exchanger

The two main Shell and Tube Heat Exchangers are;

• Fixed Tubesheet Heat Exchanger

• U-Tube Heat Exchanger

Before we dive into the calculations, lets discuss the advantages and disadvantages of both type of Shell and Tube Heat Exchanger.

U-Tube Heat Exchanger Advatages:

1. Because one of the tube is not restricted, it will be able to cater higher thermal expansion. Therefore it is suitable for high temperature difference.

2. Because it is not restricted at one end, maintenance team will be able to take out the tube bundles and mechanical cleaning can be performed at the shell side.

Disadvantages:

1. Layout engineer must take into consideration the maintenance area required when the tube is taken out. You must not missed this requirement at the design stage.

2. Its difficult to spot any external tube corrosion due to internal tubes are not visible (sandwiched).

3. Maximum two passes arrangement only.

Fixed Tubesheet HEX Advantages

1. Not requiring space to pull out the bundle.

2. More tube passes arrangement - better heat transfer.

3. Less pressure drop due to straight line tubes arrangement.

Disadvatages:

1. Require thermal expansion joint for shell to accomodate high thermal expansion.

2. Unable to perform mechancial cleaning at shell side - only chemical cleaning/high pressure water jet cleaning.

3. In-situ repair activity for tube bundle or require to take out whole bundle from site.

Below table shows different type of Shell and Tube Heatexchanger as per TEMA:

Note: TEMA is The Tubular Exchange Manufacturers Association.

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