Plate heat exchanger

Structural Principle

Basic Structure

Plate heat exchangers mainly consist of heat transfer plates, gaskets, clamping devices (such as clamping bolts and clamping plates), and a frame. The heat transfer plates are the core component, typically made of stainless steel, titanium alloy, or other metallic materials, possessing good thermal conductivity and corrosion resistance.

Gaskets seal the plates to prevent mixing of the two fluids. Clamping devices are used to press the plate assembly together, ensuring tight contact and sealing performance between the plates.

Working Principle

The working principle of a plate heat exchanger is based on heat conduction. Two fluids at different temperatures flow in adjacent plate channels, and heat is transferred from the high-temperature fluid to the low-temperature fluid through the plates, achieving heat exchange.

Due to the corrugated shape of the plates, turbulence is created within the channels, increasing the contact area between the fluid and the plates and improving heat exchange efficiency.

Features

Advantages

High heat exchange efficiency: Due to the corrugated design of the plates, the fluid forms turbulence within the channels, increasing the contact area between the fluid and the plates. The heat transfer coefficient is typically 35 times higher than that of shell-and-tube heat exchangers.

Compact structure: Large heat exchange area per unit volume, saving space and facilitating installation and maintenance.

High flexibility: The heat exchange area can be easily adjusted by increasing or decreasing the number of plates to adapt to different heat exchange requirements.

Easy cleaning: The plates are easy to disassemble and clean, preventing dirt accumulation from affecting heat exchange performance.

Disadvantages

High sealing requirements: Because the plates are sealed with gaskets, the quality and installation of the gaskets are crucial. Damage to the gaskets can easily lead to fluid leakage.

Limited pressure resistance: Compared to shell-and-tube heat exchangers, plate heat exchangers have relatively weaker pressure resistance and are generally suitable for medium to low pressure applications.

High water quality requirements: If the fluid contains a large number of impurities or particles, it can easily clog the plate channels, affecting heat exchange performance. Fluid pretreatment is required.

Application Areas

Industrial Sector

Chemical Industry: Used for heat recovery and regulation in various chemical reaction processes, such as heat recovery in the ammonia synthesis tower during ammonia production.

Food Processing Industry: Used for heating, cooling, and sterilization processes in food, such as milk pasteurization and fruit juice concentration. It provides good hygiene, ensuring food quality and safety.

Pharmaceutical Industry: Used for heating, cooling, and evaporating drug solutions during pharmaceutical production, meeting strict hygiene and quality standards.

Metallurgical Industry: Used for cooling high-temperature melts and recovering waste heat, improving energy efficiency and reducing production costs.

Civilian Sector

Heating Systems: In centralized heating systems, used for heat exchange in heating stations, transferring heat from the heating network's hot water to the user's hot water system, improving heating efficiency.

Air Conditioning Systems: In central air conditioning systems, used for heat exchange between cooling water and chilled water, ensuring the normal operation of the air conditioning system.

Selection and Maintenance

Selection Key Points

Heat Exchange Calculation: Determine the heat to be transferred based on process requirements and select an appropriate heat exchange area.

Fluid Properties: Consider factors such as fluid temperature, pressure, flow rate, and corrosivity to select suitable plate materials and gaskets.

Installation Space: Select the appropriate plate heat exchanger model and size based on the available installation space.

Economy: Comprehensively consider the purchase cost, operating cost, and maintenance cost to select equipment with a high cost-performance ratio.

Maintenance Measures

Regular Inspection: Regularly inspect the wear condition of the gaskets and replace damaged gaskets promptly to prevent fluid leakage.

Cleaning and Maintenance: Regularly disassemble and clean the plates to remove dirt and ensure heat exchange efficiency. Use appropriate cleaning agents to avoid corrosion of the plates.

Overload Prevention: Avoid operating the equipment under conditions exceeding design pressure and temperature to prevent equipment damage.

Record Operating Parameters: Record the equipment's operating parameters, such as fluid temperature, pressure, and flow rate, to facilitate timely detection and handling of abnormalities.

Plate heat exchangers are high-performance heat exchange devices with broad application prospects. In practical applications, the appropriate model should be selected based on specific needs, and maintenance and management should be strengthened to ensure their long-term stable operation.