Research Of Adsorbing Trace Ethane With Activated Carbon

Recovery of carbon dioxide is significantly important to mitigate the "greenhouse effect" and to use of resources optimally. Trace ethane is difficultl to remove in industry. Therefore, selecting an approptiate adsorbent plays a key role in this problem.Firstly, various adsorbents were investigated to compare the adsorption performance of trace ethane and the coconut shell-based activated carbon, which has a high surface area, rich pore structure and diverse surface chemical groups, was chosed as the best adsorbent. The effects of feed gas velocity and particle size on adsorption capacity were studied. The results showed that activated carbon’s adsorption capacity decreased with the increasing of the velocity and paticle size. But low velocity and small paticle size are’t conducive to industrial applications. The best conditions:the velocity,80mL/min; the particle size,20-40 mesh.ZnO3 and H3PO4 acted as the activation agent of secondary activation. The effect of activation and impregnated conditons were studied.With ZnCl2 as the activator, the main fators affecting the C2H6 adsorbance were prioritized by orthogonal experiments and then examined by single factor experiment. The most optimal conditions were:impregnation ratio,0.5; activation temperature,650℃; impregnation time,24 h; impregnation temperature,50 ℃; activation time,4 h. Breakthrough adsorbance achieved 201.6 ugg-1, increasing 88%. In addition, the effect of mixing methods was also investigated. The results showed that, compare to treating with physical mixing method, the chemical impregnation treated samples exhibited a higher adsobance due to a uniform disperse in activation. It was better than physical mixing and presented a high adsorbance. The regeneration of the samples was preliminarily tested. The samples can be used four cycles.The samples were characterized by N2 phsical adsorption, FTIR, XRD, SEM. The results indicated secondary activation developed a higher surface area and uniform pore size distribution.The crystallite structure reduced slightly.The effect of various factors was investigated using H3PO4 as the activator. The optimal conditions were:activation temperature,300 ℃; dipping ratio,0.8; activation time,2 h: dipping time,3 h. The adsorbance achieved 246.4 ugg-1, increasing 129%. H3PO4 is a more suitable as the activator than ZnCl2 due to low activation temperature and high yield.