Springer Iranian Journal of Science and Technology (Sciences) 1028-6276 Articles in Press 2016 03 16 Hydrodynamic Study of an Ebullated-bed Reactor in the H-Oil Process 3636 10.22099/ijsts.2016.3636 EN Mohammad Fadhil Abid Chemical Engineering Department-University of Technology Shakir Mahmood Ahmed SCOP-Ministry of Oil Halah Hussein Hassan Chemical Engineering Department- University of Technology Dawood Al-Mousely Faculty of Chemical and Biochemical Engineering, Western University Shahzad Barghi Faculty of Chemical and Biochemical Engineering, Western University Journal Article 2015 09 07 The effectiveness and performance of industrial hydro-processing ebullated bed reactors are highly dependent on the bed hydrodynamics and operating conditions. Hydrodynamics of ebullated bed reactors was studied in a cold model experimental setup. The results of a dynamic similarity test showed that the experimental data could be applied in the study of a large scale unit (Refinery of Lukoil, Burgas, Bulgaria) within a reasonable accuracy. Air and magnesium sulfate 20 wt.% (MgSO4 + H2O) solution and solid catalyst particles were used as the gas, liquid and solid phases respectively. For design of experiments in the lab-scale cold-flow column, factorial method was introduced to study the influence of operating variables on the individual holdups and bubble characteristics. Pressure gradient method was used to estimate the individual holdups and bed porosity along the column, while photographic method was utilized to obtain images of the moving gas bubble. The images were analyzed using Ai Adobe illustrator CC (64 Bit) software to determine the bubbles geometric characteristics. Large gas bubbles were broken to smaller ones due to the increased turbulent intensity and shear forces at higher liquid velocities, reducing mass transfer resistances. Empirical correlations were developed for prediction of phase holdups and bed porosity with high accuracy. The results showed that liquid internal reflux ratio, which characterized the ebullated bed reactors has a predominant effect on the individual holdups and bubble size. A good agreement was observed between the results and available data in the literature.