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The pressure gradient and the static and the dynamic holdup have been measured for a system consisting ofa Fluid Cracking Catalyst (FCC) of 30-150 x 10m6 m diameter, trickling over a packed bed and with a gas streaming in countercurrent flow. The experiments were carried out at ambient conditions using a glass column of 25 x 10 ~' m diameter. The packing material consisted of 8 x 8 x 3 mm ceramic Raschig rings, a mixture of 7 x 7 x 1 mm glass Raschig rings and 5 x 5 mm catalyst pellets and of stacked Kerapak ceramic mixing units of Sulzer, each unit 50 mm long and 25 mm in diameter. Four different gases have been tested. A correlation for the pressure gradient in the preloading region is derived based on the Ergun equation and taking into account the internal gas recirculation due to the solids trickles. The void fraction of the trickles is found to be independent of-the physical properties of the gas phase. The behaviour of the GSTF-system in the preloading regime and the phenomena of loading and flooding are discussed. A correlation is given which relates the boundary between preloading and loading with the particle and gas properties and the solids flow rate.

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Abstract-Thekinetics of the low pressure synthesis of methanol from feed gases containing solely CO and H, were studied in an internally recycled gradientless reactor. As experimental accuracy impeded the application of high CO contents, the experimental range of mole fraction of CO was limited to 0.04 to 0.22. The total pressure was varied from 3 to 7 MPa and the temperature from 503 to 553 K. Residence time distribution experiments confirmed the assumption of perfect mixing on a macroscale. A maximum likelihood approach was used to fit possible kinetic equations.Although more accurate results and better fits+ompared to previous experiments in a simple integral reactor were obtained, no single rate expression could be selected as the most appropriate one. This was mainly attributed to the effects of small amounts of CO, and H,O formed in the reactor. Three different reaction rate equations fit the experiments equally well. Arguments are given that we never can expect to elucidate the reaction mechanisms on the basis of kinetic experiments.

The activity coefficients of methanol in sulfolane, tetraethylene glycol dimethyl ether (TEGDME) and 18-crown-6 under conditions of equilibrium have been determined in the temperature range 423-503 K and in the pressure range 0. 28-3.5 MPa. A minimum in the activity coefficient was found for the methanol-TEGDME and methanol-l 8-crown-6 solutions. Tab IO-(I3) Kurzfassung