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08.04.2025

Plate Heat Exchanger Plate Cleaning Frequency: Comprehensive Technical Guide

Introduction

Plate heat exchangers (PHE - Plate Heat Exchanger) are efficient heat transfer equipment commonly used in industrial facilities, HVAC systems, food and beverage production, chemical plants, and power plants.
However, regular cleaning is critical for plate heat exchangers to maintain efficient operation.
This article will comprehensively cover factors affecting cleaning frequency in plate heat exchangers, cleaning methods, indicators and criteria, cleaning planning, maintenance procedures, and best practices.

1. Importance of Contamination in Plate Heat Exchangers

Loss of Efficiency: Accumulated dirt on plates insulates the heat transfer surface, reducing heat transfer efficiency.
Increase in Pressure Drop: Contaminated plates create additional resistance in fluid flow, increasing system pressure losses.
Increase in Energy Consumption: Pump and system loads increase, leading to higher energy costs.
Corrosion and Plate Damage: Contamination, especially in aggressive environments, can lead to localized corrosion and plate damage.
Decrease in Product Quality: Especially in the food, pharmaceutical, and chemical industries, product purity is compromised.
Unplanned Downtime and Repair Costs: Failure to clean can lead to emergency interventions and high repair costs.

2. Factors Affecting Plate Cleaning Frequency

2.1 Process Characteristics

Fluid Type
- Highly contaminated water, seawater, process chemicals, or viscous fluids lead to faster contamination.
Temperature and Pressure Conditions
- High temperatures accelerate fouling and deposit formation.
Total Dissolved Solids (TDS) Levels
- High TDS values increase scale and mineral accumulation.
pH Level
- Acidic or alkaline fluids can leave different types of deposits.

2.2 Exchanger Design and Material

Plate Structure and Pattern
- Patterns that create high turbulence (e.g., chevron type) can reduce dirt accumulation.
Material Selection
- The chemical resistance of materials like stainless steel, titanium, nickel affects dirt formation.

2.3 Operating Conditions

Operating Hours
- Systems operating 24/7 may require more frequent cleaning.
Flow Variations
- Low flow facilitates fouling.
System Failures or Stop-Start Operations
- Sudden stops increase deposit accumulation.

3. Signs Indicating the Need for Cleaning in Plate Heat Exchangers

Decrease in heat transfer efficiency
Outlet temperatures falling below target
Increase in system pressure drop
Decrease in fluid flow rate
Increase in pump or system loads
Visible dirt, mineral, or biofilm layers on plate surfaces

4. Approaches to Deciding Cleaning Frequency

4.1 Time-Based Planning

Annual or Biannual Maintenance
- Standard practice recommends cleaning at least once a year.
Seasonal Maintenance
- Detailed cleaning is done at the end of the cooling season.

4.2 Condition-Based Maintenance Planning

Monitoring with Pressure and Temperature Sensors
- Cleaning is done when pressure loss exceeds a certain percentage.
Measurement of Heat Transfer Efficiency
- A 10-15% efficiency loss triggers cleaning.

4.3 Online Cleaning (CIP - Cleaning In Place) and Offline Cleaning

CIP Systems
- Enables on-site cleaning without dismantling the system, can be applied at frequent intervals.
Offline Cleaning
- In case of heavy contamination, the exchanger is dismantled and cleaned manually or in a chemical bath.

5. Plate Cleaning Methods

5.1 Chemical Cleaning

Acidic Cleaning (e.g., 5% HNO₃ or 5% H₃PO₄)
- Used to remove mineral and scale deposits.
Alkaline Cleaning (e.g., 2-3% NaOH)
- Suitable for organic pollutants and oils.
Neutral pH Cleaning Solutions
- Preferred for sensitive plates.

5.2 Mechanical Cleaning

Brush Cleaning
- Plates are carefully brushed to remove deposits.
Use of Pressurized Water or Air
- Surface deposits are physically removed.

5.3 Ultrasonic Cleaning

In sensitive systems, vibrations are used to remove microscopic dirt from plates.

6. Creating Cleaning and Maintenance Plan

Maintenance Record Keeping
- Cleaning date, chemicals used, observations are recorded.
Measurement of Cleaning Performance
- Pressure drop and temperature data are evaluated after cleaning.
Preventive Maintenance Programs
- Routine maintenance and inspection schedules should be established.
Spare Parts Management
- Gaskets and plate stocks should be checked, orders placed in advance if necessary.