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PLATE FRAME HEAT EXCHANGER

Design of PHE. LMTD Methode- NTU Method. engineering-resource.com. LMTD Method . the fluid flow rates and inlet temperatures, as well as a desired outlet temperature, are prescribed.If the LMTD method is used in performance calculations for which both outlet temperatures must be determined from

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PLATE FRAME HEAT EXCHANGER

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    1. PLATE & FRAME HEAT EXCHANGER By Farhan Ahmad Department of Chemical Engineering, University of Engineering & Technology Lahore engineering-resource.com

    2. Design of PHE LMTD Method e- NTU Method engineering-resource.com

    3. LMTD Method the fluid flow rates and inlet temperatures, as well as a desired outlet temperature, are prescribed. If the LMTD method is used in performance calculations for which both outlet temperatures must be determined from knowledge of the inlet temperatures, the solution procedure is iterative. For both design and performance calculations, the effectiveness-NTU method may be used without iteration. engineering-resource.com

    4. e- NTU Method Effectiveness Capacity rates engineering-resource.com

    5. e- NTU Method 1. Calculate the heat load, q, and from it determine the inlet and outlet temperatures for both the fluids. 2. Calculate the bulk mean temperature and determine the thermo physical fluid properties. Estimate the heat capacity rate ratio, C*. 3. Estimate the heat-transfer effectiveness, E, using the relation 4. Assuming infinite number of channels then Find the required NTU using the appropriate E-NTU relation. 5 . Estimate Reynolds number for the each stream, assuming an exchanger containing one thermal plate, and one pass for each stream. 6. Calculate the heat-transfer coefficient on both sides. Estimate the overall heat-transfer coefficient, taking into account the wall thermal resistance. engineering-resource.com

    6. For series flow : 7. Estimate the approximate number of thermal plates using the equation where ?tm is the mean temperature difference. 8. Assuming an exchanger of N + 1 channels, determine NTU from the appropriate E-NTU relationship. 9. Recalculate N from Eq. 10. Repeat calculations in steps 8 and 9 until the calculated value of N in step 9 matches the assumed value in step 8. e- NTU Method engineering-resource.com

    7. For parallel flow or looped flow In a design involving looped flow patterns, the overall coefficient requires recalculation during each iteration because the channel flow rates become less with the addition of channels in parallel. The calculation procedure for looped flow is as follows: 7. Assuming an exchanger of N thermal plates, calculate the overall heat-transfer coefficient as in step 6. 8. Estimate the approximate number of thermal plates using Eq. 9. Assuming an exchanger of N + 1 channels, determine NTU from the appropriate E-NTU relationship for looped flow. 10. Recalculate the overall heat-transfer coefficient as per step 6 and recalculate N with Eq. 11. Repeat calculations in steps 9 and 10 until the calculated value of N matches with the assumed value. e- NTU Method engineering-resource.com

    8. Heat Transfer Correlations engineering-resource.com

    9. Friction factor Comparison Pressure drop in PHE Expressions for pressure drop Inlet or outlet ports Associated with plate flow passage Due to elevation changes Specific pressure drop Pressure drop Correlations engineering-resource.com

    10. Types of Plates engineering-resource.com

    11. High or Low Theta plates engineering-resource.com

    12. High or Low Theta plates engineering-resource.com

    13. Plate - Corrugation and Channels engineering-resource.com

    14. Flow Arrangements - PHE engineering-resource.com

    15. Plate - corrugation and channels engineering-resource.com

    16. Problem Design an exchanger to sub-cool condensate from a methanol condenser from 95 °C to 40°C. Flow-rate of methanol 100,000 kg/h. Brackish water will be used as the coolant, with a temperature rise from 25° to 40°C. engineering-resource.com

    17. engineering-resource.com

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