煤吸附CO_2、O_2和N_2的能力与竞争性差异

Differences of ability and competitiveness on coal adsorbing CO_2,O_2 and N_2

应用Materials Studio软件,采用巨正则系综蒙特卡洛方法,依据电厂烟气注入采空区防火与封存实际,对煤吸附CO_2、O_2和N_2的能力与竞争性差异进行分析。由计算结果可知,相比于吸附O_2、N_2,煤吸附单组分CO_2除了范德华能起主要作用,还有很强的静电作用能。由相互作用能和等量吸附热计算结果可知,煤容易吸附CO_2,而不容易吸附O_2和N_2。298.15 K时,CO_2对N_2和O_2吸附选择性及O_2对N_2的吸附选择性分别为42.396、32.357和1.310,揭示了竞争能力大小为CO_2>O_2>N_2。分压分别为CO_216.5 k Pa+N_279 k Pa+O_24.5 k Pa内系统竞争吸附时,受吸附能力、竞争性和分压影响,CO_2被大量吸附,而O_2吸附抑制。

Using Materials Studio software and the grand canonical Monte Carlo method,differences in ability and competitiveness of coal adsorbing CO=, 02 and N2 were analyzed according to the practice of injecting power plant flue gas to gob to fire protection and CO2 capture and storage. The simulation results showed that the energy involved in coal adsorbing single CO2 ,O2 and N2 molecules was Van Der Waals energy, but electrostatic interac- tion energy was also strong for CO2 adsorption. Coal adsorbed CO2 rather than 02 and N2 ,as indicated by interac- tion energy and isosteric heat calculations. At 298. 15 K,the adsorption selectivity of CO2 to N2 ,CO2 to 02 ,and 02 to N2 were 42. 396,32. 357 and 1. 310, respectively, which revealed that the competitive ability relation was CO= 〉 02 〉 N2. When the mixture system （ CO216.5 kPa ＋ N279 kPa ＋ O24.5 kPa） was adsorbed competitively, CO2 was largely adsorbed, whereas 02 was adsorbed only slightly, affected by the adsorption ability, competitive- ness and pressure.