Preparation and operating conditions for cobalt cerium oxide catalysts used in the conversion of synthesis gas into light olefins

Abstract

Cobalt cerium oxides, prepared using a co-precipitation procedure, were studied as catalysts for the conversion of synthesis gas to light olefins (C 2 -C 4 ). Specifically, we studied the effect of a range of preparation variables, including the molar ratio of the [Co]/[Ce] of the precipitation solution, ageing time and calcination temperature. In addition, the effects of supports and promoters on the catalysts' activity and selectivity and a range of reaction temperatures using synthesis gas with different H 2 /CO molar feed ratios were investigated. The catalyst containing a molar ratio of 80% Co and 20% Ce, aged for 2 h, supported with 15 wt% SiO 2 without any promoter, at an operating temperature of 450 ºC and an H 2 /CO feed ratio of 2/1 (GHSV = 4500 h -1 ), performed optimally for the conversion of synthesis gas to light olefins. The characterization of both the precursors and the calcined catalysts by powder X-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller specific surface area measurements and thermal analysis methods, including TGA and DSC, show that all the preparation variables influenced the catalyst precursor structure.

Kinetic study of CO hydrogenation over co-precipitated iron–nickel catalyst

“…It is generally accepted that operation condition variables such as temperature, pressure, H 2 /CO feed ratio and gas space velocity influence the product distributions in FT synthesis [23][24][25][26]. The catalyst was reduced in atmospheric pressure in a flow stream of H 2 with flow rate of 30 ml/min at 673 K for 12 h and then it was exposure the stream of H 2 + CO. 103 kinetic tests were carried out over 40%Fe 60%Ni and 5% Al 2 O 3 on the bases of total catalyst weight.…”

Effect of calcination conditions on the structure and catalytic performance of MgO supported Fe–Co–Mn catalyst for CO hydrogenation

“…After formation of catalyst precursor, further heat treatment is required to transform the catalyst precursor into the useful catalyst shape. In our previous works (Mirzaei et al, 2007;Mirzaei et al, 2008;Mirzaei et al, 2011) we demonstrated the importance of calcination conditions with respect to the catalyst activity for the hydrogenation of CO using mixed cobalt cerium oxides catalysts. The obtained results of these investigations have shown that the changes in the calcination conditions of the precipitates obtained by co-precipitation leads to phase changes toward forms that are more thermodynamically stable.…”

Structural characteristics of supported cobalt–cerium oxide catalysts used in Fischer–Tropsch synthesis

“…The experiments were carried out in a fixed bed tubular stainless steel micro reactor; different parts of the catalyst testing set up was explained in our previous work (Mirzaei et al, 2007). The detailed characteristics of the micro fixed bed reactor are illustrated in Fig.…”

“…The preparation steps in detailed were previously explained in our previous work (Mirzaei et al, 2007).…”