SHELL & TUBE HEAT EXCHANGER

SHELL & TUBE HEAT EXCHANGER

Shell and tube heat exchangers are the most widely used type of heat exchanger.

GENERAL INFORMATION

The inside of the exchanger contains many tubes and baffles, as shown in the picture below. These tubes and baffles help direct the two streams flowing through the exchanger.

STRAIGHT TUBE SHELL & TUBE HEAT EXCHENGER

STRAIGHT TUBE SHELL & TUBE HEAT EXCHENGER

A shell and tube heat exchanger consists of several tubes enclosed in a shell. One fluid flows through the tubes while the other fluid is conducted through the shell. Flow through the shell and tubes can be countercurrent, cocurrent, or cross flow. In countercurrent flow, the shell fluid flows in the opposite direction of the tube fluid. In cocurrent flow the shell fluid flows in the same direction as the tube fluid. Lastly, in cross flow the shell fluid flows perpendicular to the flow of the tube fluid. In general, countercurrent flow results in the most efficient heat transfer.

U TUBE SHELL & TUBE HEAT EXCHENGER

The baffles serve two functions: Their strategic positioning supports the tubes, preventing vibration and sagging, and they also channel the fluid in the shell side, resulting in more efficient heat transfer.

U TUBE SHELL & TUBE HEAT EXCHENGER

Static mixers are sometimes placed in the tubes of the shell and tube exchangers to help dissipate heat. Mixing of the fluids in the tube removes temperature, velocity, and material composition gradients. Static mixers also allow fluids to be cooled near their freezing temperature without plugging the tubes.

Static mixer

The diagram below shows the mixing that occurs as the flow in the tube encounters the static mixer. The mixer itself does not move.

Static mixer

ADVANTAGES	DISADVANTAGES
Can handle fluids at high temperatures and pressures. Can handle fluids of all states. Easy to dismantle for cleaning or repairs. Design can be adapted to meet operating conditions.	One unit can only be used for one duty. High amounts of heat loss occur, so insulation is required. Larger space requirements and more expensive than plate and frame. Over time vibrations may damage the heat exchanger. Baffle placement may be optimized to reduce vibrations and help the heat exchanger last longer.