الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The goal of the present work was to develop a new heterogeneous stirred tank reactor suitable for conducting liquid solid diffusion-controlled reactions. The agitated vessel was fitted with a fixed bed of iron solid cylinders placed at the bottom of the vessel. The performance of the reactor in conducting diffusion-controlled reactions was evaluated in terms of the mass transfer coefficient under different operating conditions such as: Impeller speed of rotation. Physical properties of the solution (viscosity, density, and diffusivity). Geometrical parameters of the bed such as particle size and bed thickness (height). Geometry of the impeller (radial flow impeller and axial flow impeller). Also, carbon cylinders with a ratio of 1 to 1 with iron cylinders were added to examine the effect of galvanic coupling on the rate of mass transfer. The present study revealed the following results: 1. The mass transfer coefficient at the agitated fixed bed was found to increase with impeller rotation speed but it decreases with increasing the cylinder diameter and the bed thickness (i.e., number of layers of packed cylinders). The productivity of the suggested fixed bed stirred tank reactor with the 90o flat blade turbine (radial flow impeller) is higher than that with 45o pitched blade turbine (axial flow impeller) for a given set of conditions. Mass transfer data were correlated using the method of dimensional analysis, the following overall mass transfer correlation were obtained For radial flow impeller: 𝑆ℎ = 0.23 𝑆𝑐 0.33 𝑅𝑒 0.99 (H/D)-0.29 For axial flow impeller: 𝑆ℎ=0.29 𝑆𝑐0.33𝑅𝑒0.94(𝐻/𝐷)−0.32 4. The galvanic action of adding carbon cylinders with the iron cylinders increased the dissolution rate of iron cylinders with a subsequent increase in the mass transfer coefficient by an amount ranging from 4.4% to 12.7% and from 3% to 15.8% for the axial and radial flow impellers, respectively depending on the operating conditions. 5.The suggested reactor can find applications in conducting heterogeneous liquid solid diffusion controlled catalytic and non-catalytic reactions such as: Catalytic removal of organic pollutants by destruction on the surface of a solid catalyst, such as a destruction of phenol on the surface of copper oxide. Catalyzed electro organic synthesis. Immobilized enzyme biochemical reactions Photochemical reactions on TiO2 catalyst. Heavy metal removal from waste solutions by cementation on a less noble metal. 6. The potential advantage of using the present reactor for conducting catalytic reactions involving gaseous reactants where the reactor acts simultaneously as a gas scrubber and catalytic reactor was pointed out, for instance, flue gas desulphurization where SO2 is absorbed and oxidized to H2SO4 on graphite.