Yeganegi Saeid, Gholampour Fatemeh
Acta Chim Slov. 2012 Dec;59(4):888-96.
Biogas is a green energy source that mainly contains CH4, CO2 ,traces of H2S and fractions of H2O vapor. One of the effective methods in biogas treatment from its pollutants is adsorptive separation. Here, enrichment of methane using (10, 10) and (6, 6) carbon nanotubes (CNTs) in modelled biogas consisting CH4, CO2 and H2S is studied. Simulations were carried out using Grand Canonical Monte Carlo (GCMC) method. Adsorption isotherms obtained at various temperatures and pressures for two single wall carbon nanotubes (SWCNTs). To quantify the separation ability of the nanotubes the adsorptive separation factors for H2S/CH4 and CO2/CH4 were calculated. For studding temperature effect, simulations at two (0.1 and 1 MPa) pressures and four temperatures: 288, 298, 318 and 338 K have been performed. In all studied conditions, CO2 is preferentially adsorbed by CNTs. Results have shown that the two separation factors are considerable, particularly for (10, 10) CNT. Additionally, the adsorption and selectivity behaviour of studied gases were considered in (6,6), (8,8) and (10,10) CNT hexagonal bundles for comparison. The results for single nanotubes were confirmed with the bundles. Hence, despite lower concentration of CO2 than CH4 and trace amount of H2S in biogas, they can be separated from methane effectively by CNTs as adsorbents. Our results showed that the CNTs can be remarkable tools in methane separation from biogas.
沼气是一种绿色能源，主要包含甲烷（CH₄）、二氧化碳（CO₂）、微量硫化氢（H₂S）和部分水蒸气（H₂O）。吸附分离是处理沼气污染物的有效方法之一。在此，研究了在由CH₄、CO₂和H₂S组成的模拟沼气中，使用（10, 10）和（6, 6）碳纳米管（CNT）富集甲烷的情况。采用巨正则蒙特卡罗（GCMC）方法进行模拟。获得了两种单壁碳纳米管（SWCNT）在不同温度和压力下的吸附等温线。为了量化纳米管的分离能力，计算了H₂S/CH₄和CO₂/CH₄的吸附分离因子。为了研究温度的影响，在0.1 MPa和1 MPa两个压力以及288 K、298 K、318 K和338 K四个温度下进行了模拟。在所有研究条件下，CO₂都优先被碳纳米管吸附。结果表明，这两个分离因子相当可观，特别是对于（10, 10）碳纳米管。此外，为了进行比较，还考虑了（6,6）、（8,8）和（10,10）碳纳米管六边形管束中所研究气体的吸附和选择性行为。单根纳米管的结果得到了管束结果的证实。因此，尽管沼气中CO₂的浓度低于CH₄且H₂S含量微量，但作为吸附剂的碳纳米管能够有效地将它们与甲烷分离。我们的结果表明，碳纳米管可以成为从沼气中分离甲烷的重要工具。
