Synthesis and Granulation of a 5A Zeolite-Based Molecular Sieve and Adsorption Equilibrium of the Oxidative Coupling of Methane Gases

Abstract

This work presents a detailed description of the synthesis of a 5A zeolite and its further granulation into molecular sieve beads. The XRD spectrum of synthesized crystals showed the characteristic peaks of a type A sodium zeolite, and XRF results of the ion-exchanged material with a calcium chloride solution allowed us to verify the formation of a 5A zeolite structure. The analysis of SEM images indicated that the granulated process generated a core−shell structure with suitable mechanical properties for industrial use. The granulated material exhibited similar properties (roundness, 96%; crush strength, 57 N; packing density, 607 kg/m 3 ; and Langmuir surface area, 410.5 m 2 /g) to most commercial molecular sieves. However, its lower water sorption capacity (0.142 kg/kg) reveals that zeolite adsorption is affected by the cementing material. Adsorption equilibrium studies at different temperatures with oxidative coupling of methane (OCM) effluent gases indicated that the material showed a higher affinity for CO 2 , followed by ethylene, ethane, and methane, whereas nitrogen was barely retained. The affinity trend was in agreement with the observed heats of adsorption, which were in the range of 13−30 kJ/mol for tested gases. Isotherms were fitted with a Langmuir model, and adsorption parameters were obtained. Regressed equilibrium equations can be used for further modeling of a swing adsorption separation for OCM effluent gases.

A Review of Porous Adsorbents for the Separation of Nitrogen from Natural Gas

“…The experimental results confirm that a greater amount of CH 4 is adsorbed compared to N 2 . These results are in good agreement with reports by Cavenati et al 67 and Garcia et al 68 Tezel and co-workers 69 compared the sorption capacity of zeolite 13X, activated carbon, and silica gel for CH 4 and N 2 sorption at 30 °C and up to 10 atm. The activated carbon exhibited the highest equilibrium adsorption capacity for CH 4 , followed by zeolite 13X and then silica gel for pure and binary components.…”

Freeze Granulated Zeolites X and A for Biogas Upgrading

“…The CO2 uptake of freeze-granulated NaX was 14% higher than of the structured NaX beads as reported by Fateme Rezaei et al [45]. Similarly, the CO2 uptake of freeze-granulated CaA was 100% higher than of the granulated CaA zeolite reported by Leonel G. et al, where the granulation approach used was nucleation and further consolidation [46]. The CO2 adsorption capacity of the freeze-granulated NaX zeolite is comparable to the NaX monolith The CO 2 uptake capacity for the NaX and CaA granules is higher than the previously reported 3D-printed NaX and CaA zeolite monoliths [44].…”

Amine Modification of Binder-Containing Zeolite 4A Bodies for Post-Combustion CO2 Capture

“…The CO 2 and N 2 adsorption capacity of Z4A bodies is found to be comparably lesser than the reported binder-free microporous zeolite 4A (100% active material), presumably due to lower volumetric efficiency . Analogously, a lower CO 2 adsorption capacity was also observed by other researchers, while dealing with the binder-containing zeolite bodies . In general, the zeolite 4A based adsorbents are being degassed at a higher temperature (300–350 °C) to get rid of the moisture .…”