CIESC Journal ›› 2021, Vol. 72 ›› Issue (8): 4196-4203.DOI: 10.11949/0438-1157.20210012

• Separation engineering • Previous Articles     Next Articles

Preparation of new granular carbon material and its efficient separation of methane and nitrogen

Qiongbin DAI(),Hongbin LIU,Qibin XIA,Xin ZHOU(),Zhong LI()   

  1. School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China
  • Received:2021-01-05 Revised:2021-03-25 Online:2021-08-05 Published:2021-08-05
  • Contact: Xin ZHOU,Zhong LI

一种新的颗粒炭材料的制备及其高效分离甲烷氮气性能

戴琼斌(),刘宏斌,夏启斌,周欣(),李忠()   

  1. 华南理工大学化学与化工学院,广东 广州 510640
  • 通讯作者: 周欣,李忠
  • 作者简介:戴琼斌(1996—),男,硕士研究生,2386421285@qq.com
  • 基金资助:
    国家自然科学基金项目(21978099)

Abstract:

Focusing on the important need for the recovery and separation of low-concentration CH4 from low-grade coalbed methane, it mainly explores the development of granular carbon adsorbents with excellent CH4/N2 separation performance using biomass as a carbon source. Granular rice grains were chosen as carbon source to prepare granular rice-based carbon materials (GRCM) by carbonization and then CO2 activation. The resulting granular carbon material exhibited a relatively narrow micropore distribution, and its BET specific surface area reached 938.529 m2/g. FT-IR analysis results show that the surface of rice-based granular carbon contains oxygen-containing functional groups such as hydroxyl and carbonyl groups. The CH4 adsorption capacity and CH4/N2 adsorption selectivity of the sample GRCM-900 are as high as 1.32 mmol/g and 5.68 (298 K and 100 kPa), respectively, comparable to most of the reported powdered carbon materials and MOF. Molecular simulation revealed the different contributions of surface hydroxyl/carboxyl/aldehyde groups of GRCM to the adsorption selectivity of CH4/N2, and the mechanism of methane and nitrogen adsorption in the slit pores of GRCM. Fixed-bed experiments confirmed that the application of GRCM carbon materials can effectively separate CH4/N2 mixtures at normal temperature, and the prepared granular GRCM have potential application prospects in recovering CH4 from low-concentration CH4 coal mine gas.

Key words: granular porous carbon, coalbed methane, adsorption isotherm, selectivity, methane, nitrogen

摘要:

主要围绕从低品位煤层气中回收分离低浓度的CH4这一重要需求,探索以生物质为碳源研制具有优良CH4/N2分离性能的颗粒炭吸附剂。选择大米碎粒作为碳源,通过碳化制备颗粒状炭前体,然后应用CO2进行活化,制备出大米基颗粒炭材料(GRCM),研究其吸附分离CH4/N2的性能。所制得的颗粒炭材料具有较窄微孔分布,其中样品GRCM-900的BET比表面积为938.529 m2/g。FT-IR分析结果显示大米基颗粒炭表面含有羟基及羰基等含氧官能团。其CH4吸附容量和CH4/N2吸附选择性分别高达1.32 mmol / g和5.68(在298 K和100 kPa条件下),优于大多数已报道的粉末状炭材料和MOF材料。分子模拟揭示了甲烷和氮气在GRCM炭材料狭缝孔道中的吸附构型和差异。固定床实验证实,应用GRCM炭材料可以在常温条件下有效地分离CH4/N2混合物,所制得的颗粒GRCM在从低品位煤层气中回收CH4方面有很好的应用前景。

关键词: 多孔颗粒炭, 煤层气, 吸附等温线, 选择性, 甲烷, 氮气

CLC Number: