In dust-laden flue gas waste heat recovery sites, ash accumulation on the outer walls of the heat exchanger tube bundle and blockage of the passages between fins lead to elevated exhaust gas temperatures and increased system resistance—conditions that operating personnel frequently encounter. The root causes of such problems are often related to how well the flue gas characteristics, fin spacing, and tube row arrangement were matched during the selection stage.
This type of heat exchanger is suitable for scenarios such as dust-laden flue gas waste heat recovery, hot air circulation heating, and drying systems. Under conditions with high flue gas dust content, the fin spacing should be appropriately increased to reduce the risk of ash bridging; for hot air circulation heating systems, attention should be paid to matching the air-side flow rate with the allowable pressure drop.
During procurement, the material combination of the base tube and fins should be clearly specified. Common options include carbon steel tubes with aluminum fins, stainless steel tubes with stainless steel fins, etc., and the selection should be determined based on the corrosiveness of the medium. The arrangement method of the finned tubes (staggered or in-line) affects heat transfer and resistance characteristics and should be noted in the technical agreement.
The upper limit of flue gas temperature fluctuations must be clearly specified in the technical agreement so that the manufacturer can adjust the fin spacing and number of tube rows, avoiding weld cracking or fin loosening caused by differences in thermal expansion. At the same time, basic parameters such as design pressure, design temperature, and allowable pressure drop should be confirmed.
When submitting technical data, technical engineers should, in addition to the medium name, preferably provide data such as inlet and outlet temperatures, flow rate, allowable pressure drop, and dust concentration, so that targeted configuration of fin spacing and number of tube rows can be made. For retrofit projects, the on-site installation space and interface orientation also need to be verified.
