Binary adsorption of CO2/CH4 in binderless beads of 13X zeolite

•We study the binary of CO2/CH4 on binderless pellets of 13X zeolite.•Experimental selectivities CO2/CH4 can reach the value 37.•Binary breakthrough data show 6 min plateaus of pure CH4.•The binary sorption data is modeled with extended Fowler isotherm.

The binary sorption CO2 and CH4 in binderless beads of 13X zeolite has been investigated between 313 and 473 K and total pressure up to 5 atm through fixed bed adsorption experiments. The amount adsorbed of CO2 and CH4 is around 4.7 mmol/gads and 0.4 mmol/gads, respectively, at 313 K and 3.7 atm in a 50/50 equimolar mixture. In a 25(CO2)/75(CH4) mixture the amount adsorbed is 4.0 and 0.84 mmol/g at the same temperature and pressure. Experimental selectivities CO2/CH4 range from 37 at a low pressure of 0.667 atm to approximately 5 at the high temperature of 423 K. Comparing these values with the ones in literature CO2 adsorption capacity is 20% higher than in CECA 13X binder pellets. The CO2/CH4 binary isotherms were fitted with the extended Fowler model that takes into account interaction between adsorbed molecules at adjacent sites suggesting a moderate attraction between CO2 and CH4. The model is validated through a graphical method using the single component isotherm parameters. The breakthrough curves measured show a plateau of pure CH4 of approximately 6 min depending of the operating conditions chosen.

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