The Benefits of Using a Gasketed Plate Heat Exchanger in Industrial Processes

Gasketed plate heat exchanger (PHEs) have become a preferred choice in many industrial applications due to their numerous advantages over conventional shell and tube exchangers. Let's examine the key benefits of gasketed PHEs that make them so popular in industrial processing.

What is a Gasketed Plate Heat Exchanger?

A gasketed plate heat exchanger consists of alternating layers of corrugated metal plates separated by gaskets. The plates are assembled between end frames and compressed via tightening bolts. The gaskets seal the system and create alternating hot and cold flow channels between the plates for heat transfer. 

Types of Gasketed Plate Heat Exchangers

Gasketed plate heat exchangers (PHEs) utilize elastomeric gaskets between the plates to seal the channels and prevent fluid mixing. They are the most common type of plate heat exchangers used in industrial applications. The main types of gasketed PHEs are:

1. Single Pass

In a single pass PHE, the hot and cold fluids flow through separate passages between the plates only once from the inlet to the outlet. This is the simplest flow arrangement.

2. Multi Pass

In a multi-pass arrangement, the fluids make several passes through the heat exchanger, reversing flow direction using turning channels and baffles. This enhances heat transfer but increases pressure drop.

3. Double Duty

This has two different fluids exchanging heat on both sides of the plate. It is essentially two heat exchangers combined into one. Double duty PHEs save space and cost.

4. Scraped Surface

These have mechanical scrapers on the plates to continuously scrape off solids or viscous deposits and prevent fouling of the plate surface. Used for crystallization, evaporation and freezing applications.

5. Wide Gap

Plates in wide gap PHEs have thicker gaskets, giving wider flow passages. This reduces fouling for fluids with particulates or fibers such as paper stock. Pressure drop is also lower.

6. Brazed Plate

Brazed PHEs use vacuum brazing instead of gaskets to seal the plates. This allows higher temperatures and pressures above 325°F and 435 psi respectively. They cannot be opened or cleaned.

7. Free Flow

Free flow PHEs have no frames or gaskets. The plates with laser welded edges are suspended from top and bottom support bars. This handle positive pressure while eliminating gasket issues.

Understanding the different types of gasketed PHEs allows selection of the optimal configuration based on process requirements like heat duty, fluid properties, pressure limits, fouling tendency, and ease of maintenance.

Benefits of Gasketed Plate Heat Exchangers

1. Compact and Lightweight

Gasketed PHEs provide extremely high heat transfer surface area per unit volume, resulting in a compact exchanger size. This saves installation space and reduces footprint. Their small size and light weight also make transportation and handling easier.

2. Ease of Maintenance and Cleaning

The plates can be easily accessed, disassembled and cleaned by removing the frame bolts. No need for special tools or lifting equipment. Gasket replacement is also simplified for maintenance.

3. Flexible Configuration

Heat transfer area can be adjusted by adding or removing plates. Plates with different patterns are available to handle diverse fluids. Multistage exchangers with interconnections are also possible.

4. Lower Fouling and Scaling

The high turbulence and velocity in plate exchangers keep particulates suspended and reduce mineral scale deposition and fouling. This minimizes cleaning frequency.

5. Higher Heat Transfer Efficiency

The corrugated plate pattern induces turbulent flow which improves heat transfer coefficients. This allows greater heat recovery compared to tubular exchangers.

6. Handle Wide Fluid Varieties

Suitable for clean fluids as well as those containing fibers, particles, viscous fluids, etc. Wide range of gasket materials available for compatibility with different chemicals.

7. Lower Capital and Operating Cost

Compact size and modular nature result in lower capital cost for a given duty compared to shell and tube exchangers. Savings from lower maintenance, cleaning and downtime also reduce operating cost.

8. Minimize Temperature Cross

Countercurrent flow and close temperature approaches result in reduced cross contamination between fluid temperatures.

9. No Leakage Between Fluids

Absence of leakage eliminates possibility of inter-fluid contamination. Useful for toxic and sterile applications.

Conclusion

Gasketed plate heat exchanger provide many advantages like compact size, high efficiency, easy maintenance, and flexible configurations that make them the top choice for heat transfer in industrial processing systems. Their lower capital and operating costs also make them an economical investment compared to conventional exchangers. Considering their numerous benefits, gasketed PHEs are here to stay as the go-to option for industrial heat exchange.