Shell and Tube Heat Exchangers

About

Shell and Tube Heat Exchangers are one of the most popular types of exchanger due to the flexibility the designer has to allow for a wide range of pressures and temperatures. this are compatible with both liquid and gas, giving them a huge range of suitable applications.

It’s important to remember when discussing heat exchangers that a “fluid” can be in a gaseous or liquid state.  Technically, it is not proper terminology to call a heat exchanger a cooler because the process fluid can be warmed as well as chilled.  For our purposes, we will focus on the cooling capabilities of a heat exchanger.  That is what RHM deals with in fluid power and lubrication applications.

Two main categories of Shell and Tube Heat Exchangers

1. Those that are used in the petrochemical industry which tend to be covered by standards from TEMA,    Tubular Exchanger Manufacturers Association (see TEMA Standards);
2. Those that are used in the power industry such as feedwater heaters and power plant condensers.

 consists of 4 major parts:

1. Front Header—this is where the fluid enters the tube-side of the exchanger. It is sometimes referred to as the Stationary Header.
2. Rear Header—this is where the tube-side fluid leaves the exchanger or where it is returned to the front header in exchangers with multiple tube-side passes.
3. Tube bundle—this comprises of the tubes, tube sheets, baffles and tie rods etc. to hold the bundle together.
4. Shell—this contains the tube bundle.

The remainder of this section concentrates on exchangers that are covered by the TEMA Standard.

Advantages

• Less costly as compared to plate type coolers.
• Can be utilized as a part of frameworks with higher working temperatures and weights.
• Pressure drop over a tube cooler is less.
• Tube leaks are effortlessly found and stopped since pressure test is simple.
• Tubular coolers in refrigeration framework can go about as recipient also.
• Using sacrificial anodes secures the entire cooling framework against erosion.
• Tube coolers might be favored for greasing up oil cooling as a result of the weight difference.

Disadvantages

• Heat exchange effectiveness is less as compared to plate type cooler.
• Cleaning and maintenance is troublesome since a tube cooler requires enough leeway toward one side to expel the tube nest.
• Capacity of tube cooler can’t be expanded.
• Requires more space in contrast with plate coolers.

Typical Applications of Shell and Tube Heat Exchangers

The shell-and-tube heat exchanger is by far the most common type of heat exchanger used in industry. It can be fabricated from a wide range of materials both metallic and non-metallic. Design pressures range from full vacuum to 6,000 psi. Design temperatures range from -250oC to 800oC. It can be used in almost all process heat transfer applications.

The shell-and-tube design is more rugged than other types of heat exchangers. It can stand more (physical and process) abuse. However, it may not be the most economical or most efficient selection especially for heat recovery applications or for highly viscous fluids. The shell-and-tube heat exchanger will perform poorly with any temperature crosses unless multiple units in series are employed.

Typical applications include condensers, reboilers and process heaters and coolers.

Images

Shell and Tube Heat Exchanger