Experiment Study For Low-concentration Toluene Recovery By Adsorption Process

Volatile organic gases(VOCs) are the main pollutants of exhaust emission in today’s industrial production processes,which will not only bring tremendous environmental production pressures to atmosphere,but also cause a huge waste of energy.Therefore,exploring a kind of cost-effective VOCs recovery technology has become a hot topic and difficult for the field of emission reduction of organic waste gases on the international.Compared with conventional gas separation technologies of absorption,condensation and membrane separation methods,adsorption method has exhibited an enormous economic competitive advantage in the governance of environment exhaust gases for industry.In our paper,adsorption recovery for methylbenzene tail gas in the production process of photoinitiators of DETX was taken as a research object.Firstly,we systematically and experimentally investigated the adsorption behaviors of methylbenzene on different adsorbents as well as the effects of adsorption temperature and adsorbent packing density on the adsorption efficiency of methylbenzene.The results of experimental studies show that active carbon fiber(ACF)is an excellent adsorbent with high adsorption selectivity for methylbenzene,and the adsorption efficiency of methylbenzene on active carbon fiber is influenced greatly by adsorption temperature and adsorbent packing density.The adsorption performance of methylbenzene decreases gradually with the increase of adsorption temperature,and the equilibrium adsorption capacity of methylbenzene decreases much obviously when adsorption temperature is greater than 40 degree centigrade,and an appropriate adsorption temperature should be inferior to 40 degree centigrade as a result.The equilibrium adsorption capacity of methylbenzene increases not clearly with an increase in adsorbent packing density,but the adsorbent packing density will cause an obvious effect on the adsorption breakthrough curve of methylbenzene.Further,a scale-up design study by simulation was carried out to validate the economic feasibility of industrialized methylbenzene recovery by adsorption technology.The calculation results of the craft display that a methylbenzene offgas with a concentration of 5026.1mg/m3 can be concentrated into a product gas with a methylbenzene concentration of 85.068%,and the recovery of methylbenzene can reach up to 96.546% and the methylbenzene concentration in process offgas is less than 60mg/m3.It realizes truly the up-to-standard release of purification for VOCs and the efficient recovery of VOCs,and then it can provide feasible strategy instruction for the effective governance and control of air pollutants with VOCs...