Study of Methanol to Formaldehyde Reaction in Fluidized Bed Reactor

Formaldehyde, as a valuable compound, has been widely used in chemical processes and is usually produced through the catalytic oxidization of methanol in a fixed bed reactor. In the present work, this reaction has been studied in a fluidized bed reactor. For this purpose, a stainless steel fluidized bed reactor , which has the capability of controlling the temperature and flow rate of the streams, has been employed. The effects of different operating variables on the performance of the above-mentioned reactor are studied. The results are compared with the two and three phase models

CFD Modeling of TiO 2 Nano-Agglomerates Hydrodynamics in a Conical Fluidized Bed Unit with Experimental Validation

ABSTRACT: In the computational fluid dynamics (CFD) modeling of gas-solids two phase flow, the effect of boundary conditions play an important role in predicting the hydrodynamic characteristics of fluidized beds. In this work, the hydrodynamics of conical fluidized bed containing dried TiO 2 nano-agglomerates were studied both experimentally and computationally. The pressure drop was obtained by pressure measurements and mean solid velocity in the different axial and radial positions and their experimental values were measured by a parallel 3-fiber optical probe. The Eulerian-Eulerian multiphase model and granular kinetic theory with using Gidaspow (1994) drag function were applied in simulations. The effect of three different types of boundary conditions (BC) including no-slip/friction, free-slip/no-friction and high-slip/small-friction which were developed b

Enhancement of the catalytic performance of H-clinoptilolite in propane-SCR-NOx process through controlled dealumination

We report for the first time the effect of clinoptilolite dealumination on the propane–SCR–NOx process. This has been accomplished using a mild acid like oxalic acid to avoid excess catalyst crystallinity deterioration. It had been shown that dealumination may result in a significant enhancement of NOx conversion to N2 when an optimum acid concentration of 0.050 M is used for a treatment period of 2 h. Dealumination substantially affects the distribution of the concentration of acid sites of different strength. The effect of dealumination on the HC-SCR activity of the zeolite samples is discussed in terms of Si/Al ratio, crystallinity, distribution of acid site strength, extra framework species concentration and textural characteristics of the samples