微纤维-活性炭双床层对苯蒸汽吸附动力学研究
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摘要
以镍纤维和活性炭为原料,采用湿法造纸与烧结工艺制备了一种微纤维吸附剂(MFS),并将MFS与常规粒状活性炭(GAC)填充床组成双床层,研究了不同初始浓度下双床层固定床对苯蒸气的吸附行为。基于Shilov方程计算了GAC床层和双床层的无效层厚度和吸附容量,并利用Yoon-Nelson方程模拟了GAC床层和双层床的穿透行为。结果表明:GAC床层和双床层的无效层厚度和吸附容量均随着苯蒸汽浓度的降低而降低;相同的苯蒸气评价浓度和比速条件下,由于置于气流末端的MFS材料能提升复合床层的传质效率,由MFS和常规GAC床层组成的双床层比单独的GAC床层具备更高的苯吸附性能; Yoon-Nelson方程模拟结果曲线与实验数据吻合良好。
Microfibrous entrapped sorbent( MFS) with nickel fibers was prepared by a traditional wet paper making/sintering process,and a double-layer bed is composed of MFS and conventional packed bed( PB) of granular activated carbon( GAC). The adsorption behaviors of benzene vapor in fixed bed at various challenge concentrations are studied. The unused layer depth and adsorption capacity of the bed are calculated using Shilov's equation. Yoon-Nelson equation is used to simulate the breakthrough behaviors of both single-and double-layer fixed beds. The results show that,for both GAC bed and double-layer fixed bed,the unused layer depth and adsorption capacity decrease with the decrease of the challenge concentration. The adsorption efficiency of double-layer fixed bed with benzene vapor is significantly improved compared with GAC bed at the same concentration ratio and flow rate,owing to that the mass transfer efficiency of double-layer bed is improved by MFS at the end of air flow. The results also show that the theoretical curves agreed with the experimental data very well.
Microfibrous entrapped sorbent( MFS) with nickel fibers was prepared by a traditional wet paper making/sintering process,and a double-layer bed is composed of MFS and conventional packed bed( PB) of granular activated carbon( GAC). The adsorption behaviors of benzene vapor in fixed bed at various challenge concentrations are studied. The unused layer depth and adsorption capacity of the bed are calculated using Shilov's equation. Yoon-Nelson equation is used to simulate the breakthrough behaviors of both single-and double-layer fixed beds. The results show that,for both GAC bed and double-layer fixed bed,the unused layer depth and adsorption capacity decrease with the decrease of the challenge concentration. The adsorption efficiency of double-layer fixed bed with benzene vapor is significantly improved compared with GAC bed at the same concentration ratio and flow rate,owing to that the mass transfer efficiency of double-layer bed is improved by MFS at the end of air flow. The results also show that the theoretical curves agreed with the experimental data very well.
引文
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[15]JONAS L A,REHRMAN J A.The rate of gas adsorption by activated carbon[J].Carbon,1974,12(2):95-101.