The heat exchange capacity and service life of a heat pipe heat exchanger largely depend on whether daily maintenance is properly carried out. Taking the circulating water cooling system of a chemical plant as an example, after 18 months of operation, the heat exchange efficiency of the heat exchanger dropped by about 15% due to ash accumulation outside the tubes and the accumulation of non-condensable gases. The following summarizes common questions about maintenance and precautions from the perspective of a technical engineer.
It is recommended to record the inlet and outlet temperatures and pressure drops on the cold and hot sides of the heat pipe heat exchanger every shift. If the cold-side outlet temperature gradually rises or the pressure drop continues to increase, check for ash accumulation outside the tubes, scaling inside the tubes, or working fluid leakage. For applications in flammable gas environments, an explosion-proof structure can be selected for the wiring cavity, and a temperature controller can be built in as needed for local adjustment and protection.
Failure of a single heat pipe often manifests as an increased local temperature difference. After shutdown, infrared temperature measurement or individual temperature difference testing can be used to locate the abnormal pipe section. When replacing heat pipes, verify the working fluid charge amount and compatibility to avoid mixing working fluids from different batches. If the system contains fluids prone to particles or scaling, the risk of channel blockage should be assessed, and filtration devices should be added if necessary.
When used in flammable gas environments, the explosion-proof structure of the wiring cavity must match the on-site explosion-proof rating, and the temperature controller setpoint should be adjusted according to the medium characteristics and process requirements. Regularly inspect flameproof surfaces and seals to ensure that protection performance is not reduced due to maintenance.
Before long-term shutdown, drain all accumulated liquid, blow off ash outside the tubes, and check the sealing of the heat pipe openings. When restarting, first conduct an airtightness test, then gradually increase temperature and pressure to avoid thermal shock. Plate-type structures are compact and have a high heat transfer coefficient, but have stricter requirements for medium cleanliness; shell-and-tube types have a wide pressure and temperature resistance range but are larger in volume under low-temperature-difference conditions. During maintenance, targeted plans should be formulated according to structural characteristics.
