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The kinetics of thermocatalytic transformations of methanol into dimethyl ether (DME) in water–methanol waste from natural gas purification on the used ASM, ASM BC, BASF KC-Trockenperlen H, BASF KC-Trockenperlen WS, and NIAP-AOS silica gel adsorbents. The physicochemical characteristics of the adsorbents were studied by low-temperature nitrogen adsorption, X-ray phase and X-ray fluorescence analysis, and scanning electron microscopy. The kinetic reaction of the thermocatalytic conversion of methanol into dimethyl ether on the ASM, ASM BC, BASF KC-Trockenperlen H, and BASF KC-Trockenperlen WS adsorbents was of the first order with respect to methanol, and it was of second order on the aluminum-oxide-based adsorbent NIAP-AOS. The activation energy values for the conversion of methanol to DME on the most effective silica gel adsorbent ASM 1 were estimated in the temperature range 160–290°C at a gas flow rate of 400 mL/min, which according to the Arrhenius dependence were 27.8 kJ/mol with an Si/Al ratio of 50.5 kJ/mol. [ABSTRACT FROM AUTHOR]

This work is devoted to a study of the life cycle of silica gel adsorbents of the ASM brand used in natural-gas purification, as well as to establishing the factors affecting their catalytic activity under the conditions of methanol conversion to dimethyl ether. The elemental and phase composition, specific surface area, and pore volume of commercial adsorbents have been established by X-ray fluorescence, X-ray phase, synchronous thermal analysis, and low-temperature nitrogen adsorption, and relationships with their catalytic activity have been studied. The dependences of the yield of dimethyl ether on the time of operation of adsorbents at gas-treatment gas-transportation units (GTUs) have been studied. It is shown that the phase state of the original, spent, and regenerated adsorbents does not change during their operation. A decrease in the thermal catalytic activity of the adsorbent under the conditions of the conversion of methanol to dimethyl ether over time during the operation of GTUs was found, which is due to a decrease in their specific surface area and specific pore volume, as well as the accumulation of various organic components (turbine oil) and sulfur. [ABSTRACT FROM AUTHOR]