Author / Editor
Karl Kolmetz
Plate Heat Exchanger Design
The approximate method given below can be used to size an exchanger for comparison
with a shell and tube exchanger, and to check performance of an existing exchanger for
new duties.
Procedure
The design procedure is similar to that for shell and tube exchangers.
1. Calculate duty, the rate of heat transfer required.
2. If the specification is incomplete, determine the unknown fluid temperature or fluid
flow rate from a heat balance.
3. Calculate the log mean temperature difference, ΔTlm.
4. Determine the log mean temperature correction factor, Ft.
5. Calculate the corrected mean temperature difference ΔTm = Ft x ΔTlm.
6. Estimate the overall heat transfer coefficient.
7. Calculate the surface area required.
8. Determined the number of plates required = total surface area/area of one plate.
9. Decide the flow arrangement and number of passes.
10. Calculate the film heat transfer coefficients for each stream.
11. Calculate the overall coefficient, allowing for fouling factors.
12. Compared the calculated with the assumed overall coefficient. If satisfactory, say
-10% to +10% error, proceed. If unsatisfactory, return to step 8 and increase or
decrease the number of plates.
13. Check the pressure drop for each stream.
The advantages and disadvantages of gasketed plate heat exchangers, compared with
conventional shell and tube exchangers are listed below :
Advantages
1. It can be easily be dissembled for cleaning.
2. The plates can be rearranged, added to, or removed from the plate rack for
difference service conditions.
3. The fluid residence time is short (low fluid volume to surface area ratio).
4. No hot or cold spots exist which could damage temperature sensitive fluids.
5. Fluid leakage between streams cannot occur unless plate material fails.
6. Fluid package due to a defective or damaged gasket is external and easily
detected.
7. Low fouling is encountered due to the high turbulence created by the plates.
8. A very small plot area is required relative to a shell and tube type heat exchanger
for the same service.
Disadvantages
1. Care must be taken by maintenance personnel to prevent damage to the gaskets
during disassembly, cleaning, and reassembly.
2. A relatively low upper design temperature limitation exists.
3. A relatively low upper design pressure limitation exists.
4. Gaskets materials are not compatible with all fluids
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Hofmann can manufacture spare parts of plate heat exchangers which is suitable for the following brands:
Karl Kolmetz
Plate Heat Exchanger Design
The approximate method given below can be used to size an exchanger for comparison
with a shell and tube exchanger, and to check performance of an existing exchanger for
new duties.
Procedure
The design procedure is similar to that for shell and tube exchangers.
1. Calculate duty, the rate of heat transfer required.
2. If the specification is incomplete, determine the unknown fluid temperature or fluid
flow rate from a heat balance.
3. Calculate the log mean temperature difference, ΔTlm.
4. Determine the log mean temperature correction factor, Ft.
5. Calculate the corrected mean temperature difference ΔTm = Ft x ΔTlm.
6. Estimate the overall heat transfer coefficient.
7. Calculate the surface area required.
8. Determined the number of plates required = total surface area/area of one plate.
9. Decide the flow arrangement and number of passes.
10. Calculate the film heat transfer coefficients for each stream.
11. Calculate the overall coefficient, allowing for fouling factors.
12. Compared the calculated with the assumed overall coefficient. If satisfactory, say
-10% to +10% error, proceed. If unsatisfactory, return to step 8 and increase or
decrease the number of plates.
13. Check the pressure drop for each stream.
The advantages and disadvantages of gasketed plate heat exchangers, compared with
conventional shell and tube exchangers are listed below :
Advantages
1. It can be easily be dissembled for cleaning.
2. The plates can be rearranged, added to, or removed from the plate rack for
difference service conditions.
3. The fluid residence time is short (low fluid volume to surface area ratio).
4. No hot or cold spots exist which could damage temperature sensitive fluids.
5. Fluid leakage between streams cannot occur unless plate material fails.
6. Fluid package due to a defective or damaged gasket is external and easily
detected.
7. Low fouling is encountered due to the high turbulence created by the plates.
8. A very small plot area is required relative to a shell and tube type heat exchanger
for the same service.
Disadvantages
1. Care must be taken by maintenance personnel to prevent damage to the gaskets
during disassembly, cleaning, and reassembly.
2. A relatively low upper design temperature limitation exists.
3. A relatively low upper design pressure limitation exists.
4. Gaskets materials are not compatible with all fluids
-----------------------------------------------------------------------------------------------------------------------
Hofmann can manufacture spare parts of plate heat exchangers which is suitable for the following brands:
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