湿法脱硫烟气中两种模拟颗粒物在CO2吸收膜上的粘附特性研究

Study of Adhesion Properties of Two Simulated Particles From Desulfurized Flue Gas on CO2 Absorption Membrane

利用原子力显微镜分析湿法脱硫净烟气中燃煤飞灰、石膏颗粒在普通玻璃、硅晶片、PVDF、PP膜上的粘附特性及颗粒间的粘附力,考察膜表面粗糙度、相对湿度、颗粒表面特性等的影响;在此基础上,开展细颗粒物单独及其与水汽共存时PP中空纤维膜组件吸收CO2性能试验。结果表明:干燥条件下,颗粒间的临界粘附力与颗粒–膜表面的临界粘附力大小并未明显差异;但在潮湿环境中,石膏颗粒–颗粒间的粘附力明显大于石膏颗粒–PP膜间的粘附力,且随相对湿度RH的提高,石膏颗粒–颗粒间的临界粘附力显著增加;颗粒单独存在时,连续运行7h后CO2吸收效率下降17.9%;颗粒物和水汽共存时,脱除效率下降18.9%;石膏–飞灰颗粒间的粘附作用可加速颗粒在膜表面的粘附沉积,是导致CO2吸收性能下降的主要因素。

Study of the adhesion properties of particle on membrane surface was investigated by atomic force microscopy(AFM). The adhesion force of a single particle with flat glass, silicon wafer, polypropylene(PP) membrane,and inter-particles were measured. The influence of surface roughness, relative humidity(RH) and particle properties on the adhesion behavior were investigated. The effects of the existence of fine particles and the coexistence of water vapor on the absorption of CO2 absorption properties of the PP hollow fiber membrane module were investigated by using self-designed CO2 membrane absorption system. The results show no obvious difference of adhesion force was obtained between the four substrates which has different surface roughness at dry condition. While in the moist environment,the adhesion force of gypsum-particle is much larger than gypsum-PP membrane. Additionally, with the increase of RH,the adhesion force of gypsum-particle increased significantly.The results show that when the fine particles exist alone, the CO2 removal efficiency decreased by 17.9% after 7 days of continuous operation. When the particles and water vapor coexisted, the removal efficiency decreased by 18.9%, The presence of water vapor had an effect on the removal efficiency but not obvious. The adhesion between gypsum and fly ash particles can accelerate the adhesion and deposition of particles on the membrane surface, which is the main factor leading to the decrease of CO2 absorption properties.