Shell and Tube Heat Exchanger Maintenance

Maintaining a shell and tube heat exchanger involves more than cleaning it at fixed intervals. Operators need to monitor working conditions, interpret performance changes and select an appropriate maintenance method. An outlet temperature that misses its target may indicate fouling, but changes in flow or problems with auxiliary equipment can cause the same symptom.

This guide explains the information needed when planning maintenance for a shell and tube heat exchanger. Opening and cleaning pressure equipment must be carried out by authorised personnel using the facility’s safe isolation, cooling, depressurisation and drainage procedures.

What signs can indicate fouling?

Reduced heating or cooling performance and a change in pressure drop under comparable operating conditions warrant investigation. Deposits on tube surfaces can affect heat transfer and flow. Alfa Laval’s shell and tube maintenance manual identifies reduced performance and increased pressure drop as possible fouling indicators.

Do not directly compare readings taken at different production loads. Separate the effects of changes in flow, inlet temperature or fluid composition, and check the accuracy of measuring instruments.

Which data support a maintenance decision?

• Inlet and outlet temperatures in both circuits.
• Flow rates and pressure drops on both sides.
• Operating load, product type and running time.
• Water quality or changes in process fluid properties.
• Previous maintenance dates, methods and post-maintenance readings.

Create a baseline record representing normal operation after commissioning. Later readings can be compared with that reference. Trends under similar loads are more useful for maintenance planning than a single measurement.

Mechanical or chemical cleaning?

The method depends on the deposit, tube material, wall thickness, seals and coating compatibility. Mechanical cleaning should avoid surface damage, while chemical products must be compatible with all wetted materials.

Not every exchanger has a removable tube bundle. Fixed-tubesheet and U-tube designs offer different access. U-bends and shell-side access can affect the cleaning method. A generic cleaning procedure should not be applied without the equipment drawing and manufacturer’s instructions.

How is performance assessed after cleaning?

Complete the necessary inspections and leak-tightness verification in accordance with the equipment instructions. After restarting, record temperatures, flows and pressure drops again. Compare results under operating conditions as close as possible to those before maintenance.

If capacity does not recover, the cause may lie elsewhere. Include valves, filters, pumps, air accumulation and changing process requirements in the review. Insufficient heat transfer surface should be distinguished from fouling.

How is the maintenance interval set?

There is no single schedule suitable for every facility. Use fluid fouling tendency, operating hours, historical records and manufacturer recommendations together. Where fouling recurs frequently, review water treatment, filtration and operating conditions rather than only increasing cleaning frequency.

Plan service clearance and component access when selecting a new exchanger. Production downtime, cleaning labour and ease of maintenance affect total cost alongside purchase price.

Frequently asked questions

Does reduced performance always mean scaling?

No. Changes in flow or inlet temperature, trapped air and auxiliary equipment problems should also be investigated.

Can all shell and tube exchangers be cleaned in the same way?

No. Construction, materials and deposit type determine the method. Follow the equipment-specific maintenance instructions.

Contact HEATMEK with your equipment details and performance records to assess a new design or replacement manufacturing requirement.