摘要
活性炭因其具有较高的选择吸附性和吸附容量已被广泛应用于CH4/N2的吸附分离研究,影响活性炭选择吸附性和吸附容量的主要物理参数之一是其微孔结构,准确地表征活性炭的微孔结构并阐明其与活性炭选择性吸附CH4/N2混合气中CH4的内在联系至关重要。为此,结合常温气体吸附法和分子探针技术,采用吸液驱气法表征了6种活性炭的微孔孔径分布,结合动态法测量得到CH4/N2分离因子,并借此分析了活性炭的微孔结构对其选择性吸附CH4/N2混合气中CH4的影响。结果表明:①与77K条件下N2吸附法测试结果相比,吸液驱气法能够测量到活性炭中更小尺寸的孔;②活性炭样品微孔孔径分布不同,其CH4/N2分离因子也不相同;③活性炭孔径小于0.48nm的微孔对其选择性吸附混合气CH4/N2中的CH4起着非常重要的作用。结论认为,吸液驱气法可为研发吸附分离CH4/N2的吸附剂提供更为准确的基础数据。
Activated carbons are widely used for CH4/N2 adsorption separation due to their high adsorption capacity and selectivity, which mainly depends on their micropore structure. Hence, it is important to characterize the micropore structure accurately and to reveal the internal relation between micropore structure of activated carbons and their selective adsorption of CH4 from the CH4/N2 mixture. In view of this, in combination with the normal-temperature gas adsorption method and the molecular probe techniques, the micropore size distribution of six kinds of activated carbons were first evaluated by spontaneous liquid-gas imbibition. Then, the CH4/N2 separation factors obtained by the dynamic measuring method were utilized to analyze the influence of micropore size of acti vated carbons on their selective adsorption of CH~ from the CI-I4/N2 mixture. The results showed that （1） the pore sizes character- ized by the spontaneous liquid-gas imbibition tend to be smaller than those by N2 adsorption at 77 K; （2） the separation factor for CH4/N2 on activated carbons changes with the micropore size distribution; and （3） the micropores of activated carbons with their si zes smaller than 0.48 nm play an important role in their selective adsorption of CH4 from the CH4/N2 mixture. Therefore, it is con- sidered that more accurate basic data for developing an adsorbent for CH4/N2 adsorption separation can be obtained with the help of spontaneous liquid-gas imbibition.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2013年第3期89-94,共6页
Natural Gas Industry
关键词
活性炭
吸液驱气
微孔孔径分布
动态法
CH4
N2分离
吸附
activated carbons, liquid-gas imbibition, micropore size distribution, dynamic method, CH4/N2 separation, adsorption
