Medium composition and concentration have been confirmed, and materials have been selected according to corrosivity—so why does pitting corrosion appear near the welds only half a year after the heat exchanger is put into operation? This problem can actually be avoided at the selection stage: material matching should not rely solely on the medium name; it must also be judged in combination with three conditions: concentration, operating temperature, and flow velocity. The following summarizes the selection and use points of hot and cold heat exchangers.
The medium contacted by the heat exchanger may be corrosive, and material selection must be determined based on medium composition, concentration, and operating temperature. The same medium shows significantly different corrosion rates on materials at different concentrations and temperature ranges. During selection, the supplier should be required to provide a material applicability statement under the corresponding working conditions, rather than simply applying conventional configurations based on the medium name.
If the area is too small, the outlet temperature will fail to reach the set value; if the area is too large, equipment investment and installation space will increase. When selecting, procurement personnel need to reasonably determine the heat exchange area and margin in combination with the load fluctuation range and control valve characteristics, and ask the supplier to provide the calculation basis for later review.
Before the equipment is positioned, the interface orientation, nozzle diameter, and maintenance space should be checked. The detachable structure facilitates cleaning and inspection of the heat exchange surface, while the fixed structure is compact and has fewer sealing points. The specific form should be determined in combination with the cleanliness of the medium and the maintenance cycle.
After commissioning, the corresponding relationship among inlet and outlet temperatures, flow rate, and pressure drop should be recorded as a reference for control valve setting and subsequent capacity expansion. The ZDR-780 hot and cold heat exchanger is suitable for conventional working conditions such as industrial circulating water and process medium cooling and heating. Specific parameters are subject to the ordering technical agreement.
