电厂氟塑钢空预器的传热与积灰性能研究

介绍一种新型氟塑钢管板式空气预热器（氟塑钢空预器）.与纯PTFE空预器相比，氟塑钢空预器综合聚四氟乙烯（PTFE）材料的耐腐蚀、不易积灰和不锈钢材料良好的传热性能和机械性能，成本大大降低.理论分析表明，相比不锈钢空预器，氟塑钢空预器多了一层氟塑料，由此产生的空预器传热能力减弱的影响可以接受.某污泥焚烧电厂的测试结果显示，清灰前和清灰后，氟塑钢空预器的传热系数均大于搪瓷空预器，污垢热阻均小于搪瓷空预器.对氟塑钢及搪瓷换热管表面烟灰的EDS及XRD分析显示，在酸环境中，搪瓷管与烟气中氧气及水反应生成铁的氧化物和铁的水合氧化物附着在换热管表面，而氟塑钢空预器几乎没有发生低温腐蚀.氟塑钢空预器可在电厂恶劣的低温腐蚀环境中应用.
Abstract: A new type of fluorine steel pipe plate air-preheater (fluoroplastic steel air-preheater) was introduced. Fluoroplastic steel air-preheater is corrosion resistant and nearly no ash deposit because of PTFE material, and has good heat transfer performance and good mechanical properties due to stainless steel. Thus, the air-preheater greatly reduced the cost compared to pure PTFE heat exchanger. Compared to stainless steel tube, fluoride plastic pipe has a layer of fluorine plastic, leading to the decrease of air-preheater's heat transfer ability, which is acceptable in theoretical analysis. The test results of fluoroplastic steel air-preheater used in a sewage sludge boiler show that the heat transfer performance of fluoroplastic steel air-preheater is better than that of the enamel air-preheater; the thermal resistance of ash deposit is much smaller than that of the enamel air-preheater. The main composition of deposits on the surfaces of fluoroplastic steel and enamel air-preheater was analyzed by using energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). Results show that in the acid environment, the enamel tubes react with oxygen and water in flue gas to produce iron oxides and hydrated oxides, which will attach to the surface of the heat transfer tubes. But the fluorine plastic steel air-preheater is almost no corrosion in the low temperature. Fluoroplastic steel air-preheater can be applied in low temperature corrosion conditions of power plants.