Adsorption dynamics of ethane from air in structured fixed beds with different microfibrous composites

Adsorption dynamics of ethane in two granular fixed beds and structured fixed beds with microfibrous composites was studied. 5A zeolite membrane 5A/PSSF(paper-like sintered stainless steel fiber) and microfibrous entrapped activated carbon(MEAC) composites were prepared by wet layup papermaking/sintering technique and in-situ hydrothermal method. Microfibrous composites were characterized by X-ray diffraction, scanning electron microscopy and N2adsorption/desorption. Structured fixed beds were designed by filling granular adsorbents(5A zeolite or activated carbon) and microfibrous composites at the inlet and outlet of the beds, respectively. Effects of flow rate, bed height and structure on the breakthrough curves were investigated. The length of unused bed(LUB) was determined, and Yoon–Nelson model was used to fit the breakthrough curves. The experimental results showed ethane was effectively adsorbed on the granular adsorbents and microfibrous composites. Both composites could decrease the LUB values and enhance bed utilization. All breakthrough curves fitted well to Yoon–Nelson model, with correlation coefficient exceeding 0.89. The adsorption rate of ethane could be improved in the structured fixed beds, which showed an enhanced mass transfer efficiency for ethane adsorption. LUB values of structured fixed beds with 5A/PSSF composites were larger, the bed utilization values were lower, and the adsorption rate constants were higher than those with MEAC composites under the same conditions.