| In order to dissolve macromolecule substances to form products, a great deal of organic solvents is used in the industrial process. Among the final products, these solvents must be removed, these results into a lot of organic exhaust gas. So, recovery of these solvents is necessary, which will bring great economic and social benefits.Acetone is widely used as an excellent organic solvent in industry. During the production of acetyl cellulose, some mixed gas is produced which includes 2% (volume concentration) of acetone vapor. This paper is focused on the dynamic adsorption performance of activated carbons for acetone reclaim.Dynamic gas-mixing and adsorption devices were built. At gas-mixing stage, the concentration in the air was predicted with the saturated vapor pressure. Gas chromatography was used for the quantitative analysis of acetone. The initial gas concentration was determined by the weight of the adsorption column. At desorption by water vapor purge stage, the concentration of acetone in the water was determined by Gas chromatography.In this paper, the adsorption capability of adsorbent AC-1 was studied. The influence of the initial gas concentration, flux and temperature was discussed. The adsorption isotherms at 273K 293K and 308K were measured and analyzed. The results show that on breakthrough, the influence of initial gas concentration and flux is more than the temperature. And for adsorption equilibrium, the influence of three factors is obvious. The measured adsorption equilibrium data of acetone on AC-1 was fitted with Langmuir equation, D-R equation and D-A equation.Five commercial activated carbons were chosen which come from different domestic factory. These ACs were compared with AC-1. The process of acetyl cellulose confirmed the experiment condition. The experimental results show that the adsorption performance of AC is closed relate with its micropore volume, and AC's microporous size distribution has a great effect on the adsorption performance. Activated carbon, which has larger micropore volume in the range of 0.5~2.0nm, issuitable for acetone recovery. It has higher used ratio of micropore and the larger adsorption capacity. AC-1 from Japan has the best adsorption capacity.The adsorption performance of regenerated adsorbent AC-1 was compared with fresh one's. The experiment results show that the microporous structure of the regenerated adsorbent has been changed, and the average diameter has been enlarged. Its adsorption capacity decreased, in particular when the initial gas concentration is less than 30g/m3.Water vapor purge and hot air flow were used to study the desorption performance of AC-1 and AC-3. The experimental results showed that the adsorption capacity of two samples declined to a stable level after desorption. Desorption by water vapor purge is fast and available, and desorption by hot air flow is slow and difficult.
|
PDF Full Text Request