Study On Temperature - Dependent Adsorption And Vacuum Desorption Of Toluene

Adsorption technology for the treatment and extraction of volatile organic compounds system is an emerging area. Research shows that adsorption technology has the advantages of strong adaptability, low operation cost, simple operation, high automation, high efficiency, good purification effect to high concentrations of organic waste gas and so on. Until now, the researches of adsorption technology include the selection of adsorbent, determination of technological process, construction of reaction device, optimization of technical parameters and determination of optimal conditions. However, the basic theory of adsorption technology is not yet complete and many conditions and influence factors are still not understood. Therefore, this study is of great significance to the promotion, application and development of this processing technology.Based on the present situation, comparison and determination of the best adsorbent, construction of experiment equipment on the basis of adsorption theory, examination of the influence factors of adsorption and vacuum desorption, determination of the optimum operating condition and exploration of the correlative mechanisms.According to the experimental results and analysis, main conclusions are listed as follows:(1) To choose the best experimental material, we made some comparison and selection of absorption ability of Activated Carbon, Molecular Sieve, Tenax TA and Resin. The result show that the maximum adsorption quantity of activated carbon is 300mg/g better than the other three materials, especially the Selling activated carbon. So we selected the selling activated carbon in the breakthrough experiment.(2) In the adsorption test, this article studied the effects of three factors of temperature, inlet concentration and gas flow rate on the treatment of toluene. The results as follows:The shapes of breakthrough curve is essentially the same no matter in temperature and gas flow rate. When the temperature and gas flow rate rise, the breakthrough curve will move to the left. The breakthrough curve is greatly affected by inlet concentration, the higher inlet concentration is, the higher mass transfer rate and greater slope of the breakthrough curve and the shorter equilibrium time.(3) In desorption regeneration test, this paper studied the effects of three factors of temperature, initial concentration of desorption column on the regeneration treatment of toluene. The results as follows:The influence of temperature to desorption is the same as adsorption, When the temperature rise, the breakthrough curve will move to the left. The desorption breakthrough curve is greatly affected by initial concentration and vacuum condition, the higher inlet concentration is, the faster desorption rate is, the greater slope of the desorption breakthrough curve.(4) Preliminary researched the purification of toluene by vacuum condition adsorption. The results show that higher vacuum condition causes rapidly increase of outlet concentration at the beginning of experiment, and the outlet concentration begin to decline immediately afterwards. When the outlet concentration reached the half of the initial concentration, the speed of desorption start to slow noticeably.