以椰壳为活性炭原材料,通过高温炭化、对KOH活化条件进行优化,制备出高比表面积活性炭,并采用CO2二次活化提高微孔材料对CH4/N2的吸附选择性,研制出高效吸附分离CH4/N2的椰壳活性炭。采用磁悬浮热天平测量了303-363K、0-1 000kPa下CH4和N2在所制备的高效椰壳活性炭上的吸附等温线,采用Toth模型对吸附平衡数据进行拟合,获得模型参数和吸附热等动力学参数。建立等温、无动量损失的双分散二级孔结构扩散模型,采用稀释穿透曲线法研究了CH4和N2在此高效椰壳活性炭上的吸附动力学。最后,通过固定床吸附分离CH4/N2的实验,研究了椰壳活性炭动态吸附分离CH4/N2机理,为优化设计CH4/N2吸附分离过程提供基础理论依据。
Coconut activated carbon with high specific surface area was prepared through carbonization of raw coconut shell and KOH activation under optimum conditions. The adsorption selectivity of CH4/N2 was improved with CO2 activation in order to prepare the high efficient coconut activated carbon for theseparation of CH4/N2. The adsorption equilibrium isotherms of CH4 and N2 on the high efficient coconutactivated carbon were measured at 303-363 K and 0-1 000 kPa in a magnetic suspension balance. The experimental data were fitted with Toth model, and the model parameters and kinetic ones such as adsorption heat were obtained. Both the isothermal bidisperse pore model and the diluted breakthrough curve experiment were used to study the adsorption kinetics of CH4 and N2 on the high efficient coconut activated carbon. Furthermore, the fixed-bed adsorption and desorption experiments were carried out to study the separation mechanism of CH4/N2 using the coconut activated carbon. The results presented herewould be significant for the development and optimization of pressure swing adsorption process forCH4/N2 effective separation using the high efficient coconut activated carbon.