Preparation Of New Granular Porous Carbon Material And Its Light Hydrocarbon Separation Performance

The development of high-efficiency separation technology for small molecule gases has an important need to replace the current traditional cryogenic separation process to reduce energy consumption.This paper mainly develops new granular carbon materials,comprehensively characterizes the surface chemistry and pore structure properties of activated carbon materials,gas adsorption and separation performance,and focuses on the realization of adsorption and separation for common small molecule gas pairs,namely N₂/CH₄,CH₄/C₂H₆/C₃H₈,C₂H₄/C₂H₆、C₃H₆/C₃H₈.This provides reference and guidance for the preparation of particulate carbon materials and their applications in the adsorption and separation of small molecule gases.The topic of this article has theoretical research and practical application value.This article mainly develops a new type of binder-free granular rice-based activated carbon and studies its performance in the adsorption and separation of N₂/CH₄,CH₄/C₂H₆/C₃H₈.No binder and chemical activator,simple preparation process are the highlights of this work.The rice-based activated carbon GRCMs show excellent performance in the adsorption and separation of two gas mixture systems.The GRCM-900 material has an adsorption capacity of 1.32 and 0.42 mmol/g for CH₄ and N₂ at 298 K and 100 k Pa,respectively.The adsorption selectivity for CH₄/N₂ is 5.68;the adsorption capacity for C₂H₆ and C₃H₈ are 3.51and 3.99,respectively,and the adsorption selectivity for C₂H₆/CH₄ and C₃H₈/CH₄ are 23 and189,respectively.The application of GRCM-850 fixed bed can achieve complete separation of N₂/CH₄,CH₄/C₂H₆/C₃H₈ mixed gas under normal temperature conditions.In this paper,high propylene selectivity granular carbon material was developed and its adsorption and separation performance of C₃H₆/C₃H₈ was studied.The key to improve the adsorption selectivity of carbon materials is to effectively narrow the pore size distribution of the prepared carbon materials by optimizing the preparation process.The selectivity of CAs series carbon materials increases with the decrease of pore size distribution.Among them,CA700 sample has the narrowest pore size distribution,mainly concentrated in the range of11-14?.Its propylene adsorption capacity is 1.3 mmol/g,and the propane adsorption capacity is only 0.11 mmol/g.Under the conditions of 298K and 100k Pa,its propylene/propane adsorption capacity ratio is as high as 11.8.Its C₃H₆/C₃H₈ selectivity is up to 10⁴;The comprehensive performance belongs to one of the best international level.The complete separation of C₃H₆/C₃H₈ binary mixture can be realized by using CA700 fixed bed under normal temperature and pressure.In this paper,ethane-selective granular coconut shell carbon material was prepared and its adsorption and separation properties of C₂H₆/C₂H₄ were studied.The carbon pore structure of granular coconut shell was regulated by high temperature CO₂ activation.The BET specific surface area and micropore volume of the modified CC-Ts samples increased,and the micropore size increased.The functional groups on the surface of the modified CC-Ts samples were-OH,C=O,methyl and methylene.The adsorption capacity of the prepared CC-850 material is 4.17 mmol/g for ethane,3.7 mmol/g for ethylene and 1.74 for selectivity at room temperature and pressure.The dynamic adsorption and separation performance of the samples was evaluated by fixed bed experiments.The results showed that CC-850 samples could be used to completely separate ethane and ethylene binary mixtures at room temperature.