CH_(4)/N_(2)分离最佳吸附剂选择的综合指标评价

Comprehensive index evaluation of optimal adsorbent selection for CH_(4)/N_(2) separation

以小麦秸秆和玉米秸秆为原料,在实验室合成了2种生物质活性炭(WSAC和CSAC),以此作为CH_(4)/N_(2)混合气中CH_(4)分离的吸附剂。在3种不同温度(303、323、343 K)下测试了纯气体(N_(2)和CH_(4))的吸附等温线,并采用SIPS模型对其关联性进行了分析,应用理想吸附溶液理论(IAST)预测了CH_(4)/N_(2)二元气体吸附平衡。用Clausius-Clapeyron方程和SIPS方程,从纯组分吸附估算了等温吸附热。将所有吸附平衡时的参数整合为一个性能指标,从气体吸附分离因子、役用性能和等量吸附热等方面评价吸附剂,以便于在具体应用相关的条件下选择最合适的吸附剂。

Two kinds of biomass activated carbon(AC) were synthesized from wheat straw(WS) and corn straw(CS) in the laboratory, which were evaluated as selective adsorbents for the separation of CH_(4) from CH_(4)/N_(2) mixtures. Adsorption isotherms of the pure gases(N_(2) and CH_(4))were performed at three different temperatures(303, 323 and 343 K)and SIPS model was used to analyze its correlation. The ideal adsorbed solution theory(IAST) was applied to predict the binary adsorption equilibrium. The isothermal heat of adsorption was estimated from the pure component adsorption data by means of the Clausius-Clapeyron equation and the SIPS equation. All the adsorption equilibrium parameters were integrated into one performance index, and the adsorbents were evaluated in terms of gas adsorption separation factor, draft performance and equal heat of adsorption, so as to select the most suitable adsorbents under the conditions related to specific applications.