复合改性表面抑制颗粒污垢积聚特性分析

Analysis of composite modified surface inhibiting particle fouling accumulation characteristics

换热设备颗粒污垢一般指悬浮在流体中的固体颗粒在换热面上的积聚。开发了一种Ni-P-TiO_(2)防垢型复合改性表面,并将之用于板式换热器抑制纳米MgO颗粒污垢在换热表面的积聚。基于搭建的板式换热器颗粒污垢热阻动态监测实验系统,研究了不同冷却水流速(0.1~0.3 m/s)、入口温度(30~40℃)及纳米MgO浓度(100~400 mg/L)对Ni-P-TiO_(2)复合改性换热表面抑垢特性的影响。结果表明,随着流速的增加,污垢热阻渐近值减小了27.85%~34.41%;随着冷却水入口温度的升高,污垢热阻渐近值减小了25.15%~39.14%;随着MgO颗粒浓度的增加,热阻渐近值减小了26.15%~45.36%。结合Ni-P-TiO_(2)复合改性表面的表面能分析了其表面的抑垢性能,发现制备的Ni-P-TiO_(2)复合改性表面的表面能与纳米MgO颗粒污垢层的表面能相接近,符合Zhao提出的“最优表面能”抑垢理论。与常规板式换热器不锈钢表面相比,Ni-P-TiO_(2)复合改性表面不仅抑制了颗粒污垢的积聚,还降低了颗粒污垢的固着强度,使得积聚其上的颗粒污垢更容易被剥离换热表面,实现了换热表面持久高效抑垢。

Particle fouling of heat exchange equipment generally refers to the accumulation of solid particles suspended in the fluid on the heat exchange surface.In this research,an anti-fouling Ni-P-TiO_(2) composite modified surface was created and applied in a plate heat exchanger to prevent the accumulation of nano-MgO particle fouling on the heat exchange surface.The effects of cooling water flow rate(0.1—0.3 m/s),input temperature(30—40℃),and nano-MgO concentration(100—400 mg/L)on the anti-fouling property of Ni-P-TiO_(2) composite modified surface were investigated experimentally.The results showed that the asymptotic values of the nano-MgO particle fouling thermal resistance on the Ni-P-TiO_(2) composite modified heat exchanger surface were significantly reduced under all experimental conditions.Compared with the original plate heat exchanger,with the cooling water flow rate increasing(0.1—0.3 m/s),the fouling thermal resistance asymptotic values on Ni-P-TiO_(2) composite surface were decreased by 27.85%—34.41%,with the cooling water inlet temperature increasing(30—40℃),the values were decreased by 25.15%—39.14%,and the values were decreased by 26.15%—45.36%with the nano-MgO particle concentration increasing(100-400 mg/L)accordingly.The antifouling property of Ni-PTiO_(2) composite modified surface was analyzed combined with the surface energy,and the surface energy of the created Ni-P-TiO_(2) composite modified surface was found to be near to the surface energy of the nano-MgO particle fouling deposition,which agreed to Zhao’s“optimal surface energy”anti-fouling theory.Compared with the 316 stainless steel surface,the Ni-P-TiO_(2) composite modified surface not only inhibited particle fouling accumulation,but also reduced particle strength of fouling deposition,so that particle fouling deposition was easier to remove from the composite modified surface,which achieved the purpose of enduring and efficient fouling inhibition and mitigation on heat exchange surface.