During on-site operation and maintenance, shell-and-tube heat exchangers often experience outlet temperature fluctuations, increased pressure drop, or localized abnormal noise. The following key points are for troubleshooting and routine maintenance reference.
When the medium temperature reaches the process setpoint, the control system adjusts the output power of the electric heater based on the temperature sensor signal through PID calculation, achieving temperature control of the resistive load of the heating element. If the outlet temperature remains low, verify whether the medium flow rate, inlet temperature, and heating power match. Note: deviations often occur under actual working conditions; after parameter confirmation, corrections should still be made based on operating data.
Increased pressure difference is usually related to scaling, blockage, or valve opening. It is recommended to inspect the baffle plate channels and the attachments on the inner and outer walls of the heat exchange tubes. The cleaning cycle should be determined based on medium cleanliness and operating duration, and should not be fixedly extended.
Leakage mostly occurs at locations where gaskets have aged or bolt pre-tightening force is uneven. After shutdown, check the sealing surface for scratches and re-tighten the bolts in a diagonal sequence. If the medium contains corrosive components, confirm the compatibility of the gasket material.
Excessively high shell-side fluid velocity may cause tube bundle vibration and generate abnormal noise. Check whether the flow velocity is within a reasonable range, and if necessary, adjust the baffle spacing or add supports.
Record the inlet and outlet temperatures, pressures, flow rates, and pressure difference trends. When parameters deviate from initial values, promptly analyze the causes to prevent minor issues from developing into shutdown failures.
