When the outlet temperature of a plate-fin heat exchanger deviates from the setpoint, operations personnel often first suspect internal leakage or blockage. In practice, the more common causes are dust accumulation in the fin channels or uneven distribution of medium flow. The BHX-75 plate-fin heat exchanger adopts a straight fin and staggered arrangement structure, making it easy to open the header for visual inspection. Recording inlet and outlet temperatures, pressures, and flow rates every shift and establishing trend records can help detect signs of a slow decline in the heat transfer coefficient in advance.
Shell-and-tube heat exchangers rely on shell-side baffles to support the tube bundle, and the shell-side pressure drop is usually relatively high, with limited heat transfer area per unit volume. The BHX-75 plate-fin heat exchanger extends the secondary heat transfer area through dense fins, making it more compact in volume under the same heat load and suitable for retrofit projects with limited space. It should be noted that the plate-fin flow channels are relatively narrow and have certain requirements for medium cleanliness, so a filter of appropriate precision should preferably be installed upstream.
Outlet temperature control depends on the coordination between the temperature transmitter and the control valve. It is recommended to calibrate the actuation accuracy of the temperature controller every six months and confirm that the outlet temperature is within the set range. During calibration, simultaneously check the insertion depth and response time of the platinum resistance sensor to avoid measurement lag caused by fouling on the thermowell. The control valve is prone to fluctuation under small opening conditions, and the PID parameters can be appropriately adjusted within the process-permitted range.
Tube-fin heat exchangers have obvious advantages in gas-gas heat exchange scenarios, but their pressure resistance is generally moderate. The BHX-75 plate-fin heat exchanger adopts a brazed or salt-bath welded structure, and the design pressure can be determined according to user operating conditions, making it suitable for high-pressure gas cooling or heating. During model selection, the medium composition, design pressure, and allowable pressure drop must be provided so that the fin parameters can be calculated. Space for tube bundle withdrawal should be reserved during on-site installation to facilitate subsequent cleaning and maintenance.
