Shell and Tube Exchangers
Shell and Tube Heat Exchanger Sizing
The required heat duty, film coefficients, conductivity, etc. for a shelland-tube heat exchanger can be calculated using the procedures in Heat Transfer Theory, Approximate U-values are given in Table 2-8.
In the basic heat transfer equation it is necessary to use the log mean temperature difference. In Equation 2-4 it was assumed that the two fluids [...]
15Sep2009 | admin | Comments Off | ContinuedTEMA Glasses and Tube Materials
TEMA standards provide for two classes of shell and tube exchanger qualities. Class C is the less stringent and is typically used in onshore applications and where the temperature is above ~20°F. Class R is normally used offshore and in cold temperature service. Table 3-2 shows the most important differences between a Class R and [...]
15Sep2009 | admin | Comments Off | ContinuedHeat Exchanger Placement of Fluid
The question always comes up of which fluid to put in the tubes and which fluid to put in the shell. Consider placing a fluid through the tubes when:
1. Special alloy materials are required for corrosion control and high temperatures.
2. Fluid is at high pressures.
3. Fluid contains vapors and non-condensable gases.
4. Fluid is scale forming.
Consider [...]
Heat Exchanger Selection of Types
In selecting an exchanger, one must know the advantages and disadvantages of each type. The three basic types of shell-and-tube exchangers are fixed tube sheet, floating head, and U-tube. Table 3-1 summarizes the comparison between these three exchangers.
14Sep2009 | admin | Comments Off | ContinuedHeat Exchangers Classification
In addition to the type description code there is also a shorthand that is used for classifying heat exchangers. The first element of the shorthand is the nominal diameter, which is the inside diameter of the shell in inches, rounded off to the nearest integer. For kettle reboilers and chillers (remember the kettle has a [...]
14Sep2009 | admin | Comments Off | ContinuedHeat Exchanger Options
There are many different arrangements of the shells, tubes and baffles in heat exchangers. Figure 3-6 is a list of TEMA standard classifications for heat exchangers, which helps to describe the various options. Theseare best understood in conjunction with the example configurations given in Figures 3-7 through 3-9.
The first letter designates the front end [...]
14Sep2009 | admin | Comments Off | ContinuedHeat Exchanger Shells
Shells up to 24-in. OD are fabricated from pipe using standard pipe nominal diameters. Standard pipe diameters and wall thicknesses are given in Volume 1, Tables 9-5 and 9-9 (1st edition: 9-4 and 9-7), Shells
larger than 24-in. in diameter are fabricated by rolling steel plate. The wall thickness of the pipe or plate used for [...]