In the hot air circulation system supporting the heater, the finned tube heat exchanger handles heat transfer between flue gas and air. Design and selection personnel must first understand the flue gas composition, dust content, and temperature fluctuation range. For working conditions with high dust content, the fin spacing should be appropriately increased to reduce ash accumulation; for occasions with frequent temperature fluctuations, the base tube material must account for thermal fatigue performance. Providing these parameters during the procurement stage helps the manufacturer make targeted configurations in fin spacing and tube material selection, avoiding reduced heat transfer efficiency or cleaning difficulties after commissioning.
The base tube can use heat-resistant alloy steel, with a design task temperature of up to 850°C, meeting the hot air circulation requirements of the heater. During selection, the long-term operating temperature should be used as the basis, with a reasonable margin reserved. The connection process between fins and base tube affects heat transfer stability, and material compatibility must be evaluated in conjunction with flue gas corrosiveness. For sulfur-containing or chlorine-containing flue gas, alloy grades should be selected cautiously, and working condition details should be communicated with the manufacturer when necessary.
For daily maintenance, soft brushes with low-pressure water or compressed air blowing are preferred. For oily conditions, neutral cleaning agents compatible with the base tube material can be used; after cleaning, rinse with clean water and blow dry. During the selection stage, confirm whether the heat exchanger has reserved sufficient maintenance space and cleaning interfaces. The fin spacing design must match the intended cleaning method to avoid brushing difficulties caused by excessively small spacing.
Before determining the model, it is recommended to verify the flue gas flow rate, inlet temperature, allowable pressure drop, and installation space. The arrangement of finned tubes affects the balance between pressure drop and heat transfer area, and must be comprehensively judged in conjunction with fan capacity. For systems with large temperature fluctuations, the manufacturer can be requested to provide explanations of thermal expansion compensation measures. Locking in the tube material and fin spacing after parameter confirmation can reduce later changes.
