Tube Bundle Extraction Sequence and Precautions for Heat Exchangers

01 Tube Bundle Extraction Sequence

When the heat exchanger is equipped with an insulation layer, first remove the insulation from the channel head and bonnet. Note that all heat exchanger insulation can be reused to reduce costs, so avoid damage during removal. Mark the heat exchanger nozzle number on the removed insulation with a marker and place it centrally.

Remove the flange bolts at the inlet and outlet, then disconnect the equipment connecting pipes. Be careful not to damage the flange faces during removal. Place the removed components nearby with clear markings for easy reinstallation. Store bolts separately with markings for centralized storage and convenient reassembly.

Remove the end covers at both ends using special tools, again taking care not to damage the flange faces. Place the removed components nearby with clear markings for easy reinstallation. Store bolts separately with markings for centralized storage and convenient reassembly.

Extract and clean the tube bundle using special tools. During the tube bundle extraction process of the heat exchanger, first pull out the tube bundle partially using the positioning lifting lugs on the tube sheet. Once the pulled-out distance allows the installation of the tube puller, use the tube puller to extract the tube bundle smoothly. Pay attention to the following aspects during extraction:

The positioning lifting lugs should be pulled out in a horizontal position to ensure the heat exchanger's slideways are in the force-bearing position (i.e., vertical direction), bearing the weight of the heat exchanger, avoiding direct force on the tube bundle, and preventing baffle plates from scratching the shell.

During hoisting, maintain the levelness of the positioning lifting lugs to ensure the tube bundle is not subjected to vertical pressure. Use professional protective sleeves for the hoisting steel ropes to avoid damaging the tube bundle (especially for coated bundles to prevent coating peeling), and provide protection at all contact points between the steel wires and the tube bundle.

After completing the tube bundle extraction, place it on a special support, usually sleepers with a surface matching the heat exchanger. Do not place the heat exchanger tube bundle directly on the ground. During placement, the connection between the tube sheet and the tube bundle should not bear force—i.e., the tube sheet should be suspended, and the sleepers should be placed under the tube bundle, preferably with the slideways in contact with the sleepers to bear force directly.

02 Precautions

Before disassembling the heat exchanger, measure and record the compression length of the tube bundle. Follow this dimension during reinstallation.

For tube bundle extraction inspection of the heat exchanger, the tube pulling machinery should have sufficient pulling and pushing force, automatic centering capability, stable center of gravity, flexible operation, and safety reliability.

During the heat exchanger tube bundle extraction, mark all removed components clearly and store them properly.

When hoisting the heat exchanger core from the tube puller to the ground, do not directly bind the tube bundle with steel wire ropes or other sharp lifting tools. When placing the tube bundle horizontally, it must be supported on the tube sheet or support plate.

Personnel participating in hoisting operations must hold valid certificates.

Hoisting the heat exchanger must have a designated commander. The commander should be an experienced individual with a high technical level and strong organizational skills, wearing distinctive identification or a safety helmet of a special color. The commander should fully understand and strictly implement the provisions of the hoisting construction technical documents.

The commander should stand in a position where they can direct all work stations; otherwise, signals should be transmitted promptly through an assistant. All signals should be unified in advance, accurate, loud, and clear.

Suspend hoisting operations in case of thunderstorms, heavy snow, low visibility, or wind speed exceeding 10.8m/s.

All personnel are prohibited from standing or walking under the boom or hoisted loads.

Use shackles with force applied along the length direction. For detachable shackles, prevent the pin from slipping. Defective shackles are strictly prohibited.

Use alternating lay steel wire ropes for hoisting. If the steel wire rope shows abnormalities such as kinking, deformation, broken wires, or corrosion, reduce its service standard or discard it promptly.

The crane should be positioned according to the specifications and location specified in the construction plan. If trenches, wells, underground pipelines, or other obstacles are found, report to the construction unit supervisor immediately for appropriate measures.

03 Inspection Content

Clean the tube bundle and shell.

Conduct a visual inspection for corrosion, cracks, and deformation of the shell, tube bundle, and components. If necessary, perform random checks using surface inspection and eddy current testing.

Inspect the anti-corrosion layer for aging and peeling.

Inspect the lining for corrosion, bulging, wrinkling, and cracks.

Inspect the sealing faces and gaskets.

Inspect fasteners for damage. Clean and inspect high-pressure bolts and nuts one by one; perform non-destructive testing if necessary.

Inspect the foundation for settlement, inclination, damage, and cracks. Check for looseness or damage of anchor bolts, shims, and other related components.