Experimental study of a fast gas-particle separator

A horizontal rapid gas-particle separator dedicated to the Fluid Catalytic Cracking process was tested on a small scale cold Circulating Fluidized Bed. Air (density 1.2 kg/m3, dynamic viscosity 1.8×10-5 Pa.s) and typical FCC particles (density 1400 kg/m3, mean diameter 70 mm) are used. The inlet gas velocity is kept constant at 7.3 m/s while the inlet solid loading and the separator dipleg back pressure range from 0 to 16 kg/kg and 100 to 500 Pa, respectively. Solid collection efficiency and pressure drop are studied. A model based on cyclone concepts is proposed. The solid collection efficiency increases with the inlet solid loading and reaches an asymptotic value close to 95 % when the inlet loading is above 5 kg/kg. Two flow regimes are observed in the separator dipleg through the range of inlet solid loadings, related to the available flow section modification and the interstitial gas entrainment. At constant gas collection efficiency, the separator pressure drop is maximum under single-phase flow conditions and reaches a minimum when the inlet solid loading is close to 2.5. The pressure drop increases again for higher inlet solid loading. The final modeling allows good prediction of the separator operation for all inlet solid loading conditions when the gas collection efficiency is at 100 %

Numerical Simulation of Fixed-Bed Catalytic Reforming Reactors: Hydrodynamics / Chemical Kinetics Coupling

Fixed bed reactors with a single fluid phase are widely used in the refining or petrochemical industries for reaction processes catalysed by a solid phase. The design criteria for industrial reactors are relatively well known. However, they rely on a one-dimensional writing and on the separate resolution of the equation of conservation of mass and energy, and of momentum. Thus, with complex geometries, the influence of hydrodynamics on the effectiveness of the catalyst bed cannot be taken into account. The calculation method proposed is based on the multi-dimensional writing and the simultaneous resolution of the local conservation equations. The example discussed concerns fixed-bed catalytic reactors. These reactors are distinguished by their annular geometry and the radial circulation of the feedstock. The flow is assumed to be axisymmetric. The reaction process is reflected by a simplified kinetic mechanism involving ten chemical species. Calculation of the hydrodynamic (mean velocities, pressure), thermal and mass fields (concentration of each species) serves to identify the influence of internal components in two industrial reactor geometries. The map of the quantity of coke formed and deposited on the catalyst, calculated by the model, reveals potential areas of poor operation

Two phase gas-liquid flows with pockets and slugs

Translated from French (Revue de l'Institut Francais du Petrole 1983 v. 38(2) p. 153-182)SIGLEAvailable from British Library Document Supply Centre- DSC:9022.048(BG-Trans--8603)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo