Step by Step Guideline for Plate and Frame Heat Exchanger Design, Sizing, Purchasing, and Installing: Save your time in designing and cross-checking vendor's design

Design and sizing of plate-and-frame heat exchangers are explained using a generally accepted method derived from heat exchanger design fundamentals. This method is sufficient to cross-check properness of vendor’s proposed designs and to avoid excessive over-and-under-sizing. This article also covers good practices in designing, specifying, purchasing, and installing plate-and-frame heat exchangers.
Plate-and-frame heat exchangers or plate heat exchangers (PHE) are a type of compact heat exchangers widely used in the food industries because of their ease of disassembly for cleaning to meet health and sanitation requirements. They were first introduced in 1930s, and their design became mature in 1960s. It has recently become more widely used in refining and petrochemical industries too under specific and appropriate conditions. They have also been proposed as a potential alternative for shell and tube heat exchangers in heat recovery networks [1,2].
PHE is mainly designed and supplied only by vendors, thus remaining a black-box for most plant engineers. Most plant engineers rely solely on vendors to propose a well-designed PHE for a specified application. It is a poor practice, though, to rely only on vendors who may not fully understand the actual fluid properties/characteristics and the actual process requirements. This often leads to the design mistakes or inadequacy of the equipment.

Scope

This article covers most practical design aspects of PHE, which have rarely been discussed in details by other articles [1-3]. It explains how to design a PHE using a generally accepted method derived from heat exchanger design fundamentals. The described method can be applied to a preliminary design of PHEs and review of the vendors’ proposed equipment for its suitability for the required service.

Table of Contents
INTRODUCTION 4
Scope 5
General Design Considerations 5
Advantages 8
Disadvantages (compared to Shell-and-Tube type): 9
Selection Criteria: PHE vs. Shell & Tube (S&T) Heat Exchangers 11
TABLE 1: Comparison between PHE and S&T heat exchangers 11
NOMENCLATURE 18
DESIGN FUNDAMENTALS 22
A. Geometric calculations 25
B. Heat Transfer Calculations 25
C. Pressure Drop Calculations 26
TABLE 2: Chevron Angles vs. Coefficients for Heat Transfer and Pressure Loss 27
TABLE 3: Nusselt Number and Convective Heat Transfer Coefficient Calculations 28
Good Practices in Designing, Specifying and Purchasing, and Installing 29
Installing plate-and-frame heat exchangers: 29
Specifying and purchasing plate-and-frame heat exchangers: 29
APPLICATION AND CALCULATION EXAMPLES 32
Application Example 1: How to confirm properness of vendor’s proposed design 32
Application Example 2: Design and Rating by Effectiveness-NTU (?-NTU) method 38
Example 2.1: Determination of Outlet Temperatures by Effectiveness-NTU (?-NTU) method 40
Example 2.2: Determination of Effect of Inlet Temperature Change on Outlet Temperature 42
REFERENCES 43
SPECIFICATION DATASHEET 44