Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX
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Experimental Measurement of Dissociation Condition for Carbon Dioxide Hydrates in the Presence of Methanol/Ethylene Glycol and CaCl2 Aqueous Solutions Majid Dastanian,† Amir Abbas Izadpanah,*,† and Masoud Mofarahi†,‡ †
Department of Chemical Engineering, Faculty of Petroleum, Gas and Petrochemical Engineering, Persian Gulf University, 75169-13817 Bushehr, Iran ‡ Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea ABSTRACT: In this study, hydrate dissociation conditions of carbon dioxide in the presence of methanol/ethylene glycol + CaCl2 at the temperature range of 262.2−276.8 K and the pressure range of 1.49−3.36 MPa, not found in the related literature, were measured and reported. The equilibrium data were conducted by isochoric pressure search method. The experimental findings showed that methanol inhibition power was superior to that of ethylene glycol at similar mass concentrations. An available thermodynamic model was used to predict and compare the results with the measured experimental data. In addition, in order to investigate the inhibitory effect of various inhibitors as well as their synergy to one another, the suppressed temperature of hydrate formation in the presence of various inhibitory solutions used in this work and also in the similar studies in the literature was examined. This measurement indicated no effect of pressure on the reduction amount of suppressed temperature for each solution, so that it can be considered to be independent of pressure. Moreover, at low concentrations synergy level of CaCl2 with methanol or ethylene glycol was negligible, indicating no effect of these two inhibitors on the performance of each other. By increasing the concentration of alcohol and glycol, this rule was interrupted and inhibitors interacted each other and the synergy level increased.
1. INTRODUCTION One of the main problems encountered during production operations as well as the transportation of natural gas is the formation of gas hydrates.1 Gas hydrates are crystalline inclusion compounds which are formed in mixtures of water and light gases such as methane, ethane, carbon dioxide, and so forth. These solids are composed of a lattice of water molecules (host) locating alongside each other through hydrogen bonds. This lattice consists of some empty cavities which are stabilized by placing small molecules (
