Synthesis and Granulation of a 5A Zeolite-Based Molecular Sieve and Adsorption Equilibrium of the Oxidative Coupling of Methane Gases Leonel Garcı ́ a, † Yuly A. Poveda, † Mohammadali Khadivi, ‡ Gerardo Rodríguez, † Oliver Gö rke, § Erik Esche, ‡ Hamid Reza Godini, ‡ Gü nter Wozny, ‡ and Alvaro Orjuela* ,† † Department of Chemical and Environmental Engineering, Grupo de Investigació n en Procesos Químicos y Bioquímicos, Universidad Nacional de Colombia, 111321, Bogota ́ D.C., Colombia ‡ Chair of Process Dynamics and Operation, Sekr, KWT-9, Technische Universitä t Berlin, Strasse des 17 Juni135, D-10623 Berlin, Germany § Institute of Materials Science and Technology, Technische Universitä t Berlin, FG Keramische Werkstoffe. Sekr. BA3. Hardenbergstr. 40, D-10623 Berlin, Germany * S Supporting Information 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. 1. INTRODUCTION Methane is envisioned as the main transition feedstock for petrochemical manufacturing in the near future. This is a consequence of the oil resources declining, the large reserves of natural, shale, and associated gas, the increasing availability of biogas (from biodigesters and landfills), and the negative climate effects of gas flaring or venting. In particular, olefins such as ethylene and propylene are petrochemical building blocks of major interest to be obtained from methane. Current industrial manufacturing of ethylene and propylene exceeds 200 million tons per year, and it is mainly conducted by steam cracking of a variety of hydrocarbon feedstocks or by the separation of light gases from catalytic cracking. 1 As an alternative route to ethylene manufacturing and since first reported, 2 the oxidative coupling of methane (OCM) has been extensively investigated. Recent reviews describe most of the developed technologies to overcome the main obstacles for OCM industrialization, 3-8 which has not yet been accom- plished partly because of the complex separations required to obtain a polymer-grade product. Current industrial processes for the isolation of high-purity olefins generally involve high-pressure cryogenic distillation in the olefin/paraffin separations. This process is extremely energy-intensive and requires large capital and operating costs. 1,9 A recent report indicates that the separation processes involved in ethylene and propylene production represent 0.3% of the world energy use. 1 Among different in situ or downstream splitting alternatives for olefin/paraffin mixtures, swing adsorption systems, simulated moving beds, membrane separations, chemical complexation, and absorption have shown promising results. 10-18 In particular, current industrial OCM technology developers (e.g., Siluria Technologies, ExxonMobil) have mostly implemented swing adsorption separations. 19-23 In either pressure or temperature swing adsorption separations, the adsorbent materials play a key role in the operating performance. A variety of zeolites, metal-organic Received: January 20, 2017 Accepted: March 23, 2017 Article pubs.acs.org/jced © XXXX American Chemical Society A DOI: 10.1021/acs.jced.7b00061 J. Chem. Eng. Data XXXX, XXX, XXX-XXX