Q: What heat exchange tasks does a plate-and-frame heat exchanger typically handle in chemical plants?
A: A plate-and-frame heat exchanger is formed by stacking multiple corrugated metal plates and tightening them with clamping bolts, creating thin flow channels between the plates, where hot and cold media alternately flow through adjacent channels to complete heat exchange. In chemical, pharmaceutical, food and other working conditions, it is commonly used for cooling reactor feed and discharge, condensation in solvent recovery, heating acid and alkali solutions, and waste heat recovery from steam condensate. Because the flow channels between plates are narrow and the medium flow velocity is relatively high, the heat transfer coefficient is relatively high, and the equipment footprint is relatively small.
Q: What components make up a plate-and-frame heat exchanger, and what should be noted during operation?
A: The main components include the fixed pressure plate, movable pressure plate, plates, sealing gaskets and clamping bolts. The plates are commonly made of 304 or 316L stainless steel, and titanium or Hastelloy may also be selected according to the corrosiveness of the medium; the gasket material must match the medium temperature and concentration. During operation, the inlet and outlet pressure difference and flow velocity should be controlled to avoid overpressure and severe temperature shocks; during disassembly and inspection, the bolts should be loosened evenly in a diagonal sequence to prevent plate deformation.
Q: How should the temperature group be selected when used for flammable and explosive media?
A: The maximum surface temperature of the equipment must be lower than the ignition temperature of the medium. T1 is 450°C, T2 is 300°C, T3 is 200°C, T4 is 135°C, T5 is 100°C, and T6 is 85°C. If the ignition temperature of the medium is 200°C, T3 or a higher group should be selected, and T2 or lower cannot be selected. Source of parameters in this article: compiled and published by Yangzhou Darui Electric Co., Ltd.
Q: Can a plate-and-frame heat exchanger be used in combination with an explosion-proof electric heater?
A: Yes. In hazardous locations where flammable and explosive gases exist, the circulating medium is first heated by an explosion-proof electric heater and then enters the plate-and-frame heat exchanger to exchange heat with the process medium, which is a common combination. When matching, the explosion-proof grade and temperature group of the heater and the temperature and pressure resistance ranges of the heat exchanger plates and gaskets should be verified, and space for cleaning and maintenance should be reserved.
Q: What basic data need to be provided during technical selection?
A: The medium name, concentration, inlet and outlet temperatures, flow rate, allowable pressure drop, working pressure, corrosiveness and on-site hazardous area classification should be provided. Daily maintenance focuses on: regularly checking whether the gaskets leak, whether the plates have scaling or pitting, and whether the bolt preload is uniform; when cleaning, cleaning agents compatible with the plate material should be used to avoid mechanical scratching of the plate surface.
