In this study, oxidative coupling of methane on Redox catalysts in fluidized bed reactor was investigated. For this purpose, the catalyst Mn-Na 2 WO 4 /SiO 2 was selected as a Redox catalyst. In order to investigate this catalyst, transient state experiments were designed and performed. Then, the different reaction conditions on this catalyst in a fluidized bed reactor were investigated. In transient state experiments, methane feed without the presence of oxygen in the gas phase was sent incrementally on the catalyst and oxidative coupling of methane was examined. Reactor output was analyzed by two systems of GC and GC-MS. The effect of different operational temperatures on the amount of production of coupling products showed that the catalyst has Redox features. With increasing catalyst bed temperature, mobility of oxygen in network increases, which leads to an increase in production. Reoxidation of catalyst bed with oxygen and repeating the experiment and the results confirmed the property of redox catalyst. Then, transient state experiments at temperatures of 800 and 850 o C were repeated with the same conditions and the percentage of methane conversion, selectivity, and mole percent of components were investigated. It was observed that at first, methane conversion is high and then as the oxygen of the catalyst and the speed decrease, methane conversion decreases dramatically. According to the chart of mole composition, when the conversion rate is high, the main products of coupling reaction are C 2 H 6 , C 2 H 4 is.
In recent years, improving the quality and composition of cement slurry has been one of the most important challenges for researchers and oil and gas well drilling industries. It has been demonstrated that, nanoparticles have made some progresses in the operational characteristics of the conventional cement. This research, via 13 experimental attempts, revealed a great improvement in compressive strength and rheological properties of the cement slurry after addition of silicon dioxide nanomaterial to the slurry. However, it did not make any significant change in the free water content of the cement and fluid loss. In the case of static gel strength analyzers (SGSA) test, transient time followed a decrementing pattern by increasing nanoparticle percentage. As a result, it met the vital goal in drilling industry via deep reduction in gas migration rate, solving the foregoing problem without having any negative effects on the other properties of the cement slurry such as thickening time. Moreover, the Mohr circles analysis demonstrated that, higher compressive strengths were achieved.
One of the main problems during oil well completion and cementing operation is fluid migration through cement bulk or behind the cemented casing. Slurry composition and characteristic have been focused and improved in last decades to mitigate gas migration and, recently, aspects such as using nanotechnology have been investigated to amend the conditions. In this research, two moderate base slurries with 95 and 120 Pound per Cubic Feet (PCF) densities containing different percentages of nanosilica have been examined using a perfect test package. The results of Fluid Migration Analyzer (FMA) demonstrated that using correct percentage of nanosilica particles modified rheological behavior of the slurries and decreased fluid migration volume. Moreover, adding nanoparticles did not have any negative effects on any conventional parameters. However, static gel strength analyzer showed significant transient time reduction which is an important key in cement setting profile. Triaxial test results together with Mohr circles analyzing presented considerable progress in cement stability and compressive strength.
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