رهبر رحیمی

In this paper, after a brief investigation of the history of chemical engineering in Iran and the world, the published papers related to chemical engineering education in the Iranian Journal of Engineering Education, on the occasion of its 25th anniversary of publication, were reviewed. In educational part of the present work, the novel educational methods such as remote education, e-learning, game-based education, virtual reality education and the outcomes of these methods are discussed. In addition, from the research perspective, the latest directions of chemical engineering such as stimuli-responsive polymeric micelles, drug delivery, cancer therapy, antimicrobial active packaging films, active food packaging, advanced electro spun nanofiber yarn-based textiles, wound healing applications, advanced technologies for water and wastewater treatment, application of nanomaterials and ionic metals, green and renewable energies, and the applications of artificial intelligence in chemical engineering were reviewed. From the foresight vision and considering the global changes such as environmental challenges, limited world resources, the novel areas of chemical engineering and its future, with emphasis on chemical engineering education, have been investigated. With progresses in many interdisciplinary areas such as energy and decarbonization, water, food, air, human health and medicine, it is being expected that great changes occur in the education of chemical engineering.

Iran, one of the largest greenhouse gas producers in the world, burns hundreds of thousands of tons of sour gases annually, through the flare systems. Sweetening of sour gases, using amin absorption process, with combination of Claus process is the most common process, with a huge amount of sulfur, as by product. In this paper, a feasibility study has been done for "catalytic conversion of H2S to methyl mercaptan" as a novel process for sweetening of sour gases. This investigation shows that the use of this method has a great benefit in comparison with the H2S -to-sulfur conversion processes. The study examined one of Iranian petrochemical companies that burns more than 80,000 tons of gas per year. The results show that by the catalytic conversion of H2S to methyl mercaptan in this petrochemical complex, while producing one of the country's most needed strategic materials, the gross profit of the project is more than 25 million US$ annually. The benefit of this method is 4 times of the H2S to Sulfur method and the total cost will return in less than two years.

Structured packings with large specific area are widely used in mass transfer processes such as distillation. Effective interfacial area is the key parameter in determination of mass transfer performance, and differs from packing specific area. In present work, different  models for predicting effective interfacial area in structured packings such as Wang, Gualito, Olujic and Brunazzi were presented and accuracy of the models were compared with experimental data of  Mellapak 250Y with respect to the pressure and surface tension of system, in terms of gas and Liquid Loads. Predictive values of Wang and Gualito models are better than others by changing pressure. The mean absolute relative error (MARE) for these models are 31% and 44%, none of these models were recommended for predicting effective interfacial area. Respectively. Brunazzi and Olujic models showed the lowest deviation from experimental data which were 8% and 7%, respectively. The results of this work could be used as a guide to select the best models available for effective interfacial area prediction, and to direct future research in this area.

A dividing wall distillation column is a separation technology in the field of process intensification that promises energy and capital savings. Dividing wall columns are applied for separation of mixtures with three and more components, such as hydrocarbons, alcohols, aldehydes, ketones, acetones, and amines. Further, DWCs can be used to conduct azeotropic, extractive and reactive distillation. Scale-up and successful operation of a commercial unit, as well as design, optimization, feasibility and risk reduction in processes require a pilot. These studies indicate that DWC, compared to conventional distillation sequence, can save 20% in equipment investment costs and 30% savings in energy consumption. Most of the studied pilots were reported to have a diameter between 50 and 700 mm and a maximum height of 12 m. The most important points in the design and construction of DWC are vapor split, wall position, number of equilibrium stages, height and diameter of the tower.

Gravity multiphase separators are one of the most important equipment in different industries. Due to the limitations related to semi-empirical models and the high-performance cost of experimental tests in finding the optimized design, computational fluid dynamics (CFD) has been widely used recently. In this research, after a total review on gravity separators, a review of CFD studies on these apparatuses, to find the appropriate model for simulation and optimization, are considered. Results show that, although CFD is a powerful technique for modeling and improving the separator design, some disadvantages like using incorrect models, simplified assumptions and inappropriate optimization methods lead to inaccurate simulation and optimization results, which should be considered in future works.

Three-phase separators are used to separate immiscible phases in petroleum industries. Computational fluid dynamics (CFD) simulation of industrial separators are rather limited in the literature and most of them are based on Eulerian-Eulerian (E-E) or Eulerian-Lagrangian (E-L) approaches with poor agreement between simulation and industrial data. In this research a coupled E-E and E-L method, i.e., the combination of the volume of fluid (VOF) and dispersed phase model (DPM) was developed to simulate an industrial three phase boot separator. Noted that despite the wide usage of boot separators in petroleum industry, no research has been performed on it. In order to develop the coupled model, effects of different sub-models including virtual mass force, droplet break up and also discrete random walk (DRW) model which was ignored in most of the researches, were considered. Liquid droplet entrainment in the gas outlet taken from data of Borzoyeh Petrochemical Company in the south of Iran, was the criteria for evaluating the CFD model. It is concluded that the coupled model using three mentioned sub-models with the high importance of applying DRW, is a successful way in predicting the separator efficiency so that considering all sub-models decreases the simulation error from 40.81% to 12.9%. Using the validated model, effects of inlet droplet size and flow rate on the separation performance were considered. Results demonstrated that decreasing droplet size (by 20%) and increasing flow rate (from 5800-6475 kg/hr), decreased the efficiency, such that the liquid entrainment in the gas outlet increased by 29% and 38 % respectively

Multiphase separation in gravity separators is one of the important processes in different industries. This study presents a computational fluid dynamics (CFD) simulation of an industrial three-phase boot separator applying a coupled volume of fluid (VOF)- dispersed phase model (DPM) method for hydrodynamic analysis and troubleshooting of the separation process. Noted that despite the wide application of the boot separator in different industries, no research has been performed on this type of separator to investigate the macroscopic and microscopic behavior of the separation process. The results of numerical calculations based on three-phase flow profile, secondary phase behavior, separator performance, and size distribution of the droplets were investigated in this research. Results showed that the CFD model is well capable of estimating the separation behavior in a threephase boot separator. Troubleshooting of the studied separator was also investigated to detect the parameters that might decrease the separation performance. Based on the results, it is concluded that the separator suffers from the type of the inlet diverter, lack of an efficient mist extractor at the gas outlet and also lack of an appropriate vortex breaker at the oil outlet. The effect of increasing the inlet water flow rate on the separator performance was another parameter that was studied in this research. Results demonstrated that increasing the inlet water flow rate from 11823-47295 kg/hr caused an increase in the mass of droplets at the gas outlet from 0.09 to 1.6 kg/hr, but this increase did not lead to a significant decrease in the separation efficiency.

It is less than 20 years that the concept of chemical product engineering and chemical product engineer is introduced by chemical engineers. The concept is introduced by US universities and followed by the EU universities afterward. They have introduced the chemical product engineering course at BSc and MSc levels. It is in some universities taught as a project at graduate level to the students.  To master the chemical product engineering the new knowledge of bio and nanosciences are essential.  The strategy for making product engineering structural consists of 4 stages which are named; The need, ideas, selections and manufacture. The production of specialty products takes place in a batch process. That is due to a low amount of production and the need for a change of products. Even though production specialty products have the risk of market rejection, but the initial profit justifies the risk. It is found unfortunate that the same trend is not followed in Iran's universities.

In this work computational fluid dynamics is used to describe the fluid flow across a randomly packed absorption tower. The CFD simulation method is employed on a packed tower that is packed with 1cm Raschig rings. Tower is 175cm in height. Air flow rate range was 1.5 to 5 m/s. The measured pressure drops were in 1.5 to 12 Pascal per height of tower in meter. The Klerk’s approach is examined to define the influence of confining walls on pressure drop in packed areas. It is concluded that CFD model that uses the Klerk’s definition of radial porosity distribution is a successful way for pressure drop prediction in packed beds. Model prediction of dry pressure drop is about 4% lower than the experimental measurements. Ergun’s pressure drop prediction is compared with that of Reichelt’s using averaged and distributed porosity profiles. In both methods Ergun’s approach in comparison with Reichelt’s approach has %6 lesser error in dry pressure drop prediction.

The distillation process remains as the most common method of separation in chemical process industry so that the energy use of this process accounts for an estimated 3% of world’s energy consumption. Different methods have been considered to reduce the energy consumption in distillation processes. As one of these methods, The Dividing-Wall Column (DWC) has been of great concern for multi-component mixtures distillation. The design of DWC is based on Thermally Coupled Distillation System (TCDS) which eliminates some of the operational equipments. That leads to reduction of 20-30% in capital costs and about 25% in operating costs. Thus Dividing-wall column (DWC) is one of the best examples of process intensification in distillation.This paper presents an introduction to DWC, including column configuration, design, simulation and some current industrial applications.

Simulation results of bubbling gas-solid fluidized bed using two-fluid model integrating the kinetic theory of granular flow are presented. Results of solid hold-up at different axial locations and radial directions are shown. Simulations are performed at high gas velocities. Particle motion and bubble behavior at two gas velocities of 0.35 and 0.9856 m/s in the bed are predicted and compared with the experimental data. Predicted results show that the gas velocity and ratio of the static bed height to width of the bed are important parameters for prediction of solid particles motions in a bubbling fluidized bed. Current work indicates the sensitivity of the CFD results to the drag model. Arastoopour’s drag model is the best choice for this study.At high gas velocity of 2.1824 m/s the standard k-e turbulent model and laminar models are compared. In general, the model predictions are in a good agreement with the experimental data. Current model reduces simulation’s errors compared with previous works. The minimum error is 8 % and the maximum error is 13.7 % in lower and upper part of the bed in radial direction, respectively.In addition, the error in axial direction is 4.5 %. The gas velocity values has a significant effect in solid particles motions.