Abstract Research Subject: Identifying and evaluating investment opportunities across the entire network of Iranian petrochemical units is of particular importance for developing the petrochemical industry's value chain, maximizing added value, and ensuring the optimal use of oil and gas resources.
Research Approach: The purpose of this research is to create a mathematical model to identify and evaluate investment opportunities by analyzing technical and economic-financial data of process units active in the Iranian petrochemical industry. This tool can process a large volume of information in a limited time and with acceptable accuracy and provide the desired output. Process information of petrochemical complexes, including operational units, production and consumption of materials, technologies used, and prices of raw materials and products, is the main data that form the basis for preparing mathematical models. In addition to process units, environmental variables affecting the system, along with their effect on the model, are also modeled and integrated with the network of process units.
Main Results: By creating a model and performing the simulation process, the various outputs of the system include: technical and economic-financial analysis, estimation of investment costs of process units, sensitivity analysis of the network of process units to technical and economic parameters and variables such as feed and product prices, as well as the operational capacity of process units. For example, to validate the simulator outputs, the actual data of the Amirkabir Petrochemical Complex were compared with the outputs obtained from the simulator, and accordingly, the error rate of the simulator was estimated to be 3.36 percent in the estimation of the production rate of main products and 22 percent in the estimation of the production rate of by-products. Finally, based on the simulator outputs, investment opportunities in the value chain of the Iranian petrochemical industry were identified, evaluated, and validated, and on this basis, the establishment of a methanol-to-olefin (MTO) conversion unit was introduced as a valid investment opportunity in the downstream part of the methanol value chain.

Abstract Abstract:
Research subject:
The use of deep eutectic solvents (DES) as an effective approach to enhance the performance of polymer membranes in CO₂ gas separation has gained significant attention. Membranes modified with DES are referred to as supported liquid membranes (SLMs).
Research approach:
In this study, two-component (choline chloride/urea) and three-component (choline chloride/urea/DBU) DES were used to improve the efficiency of Pebax-1657 (poly(ether-block-amide)) membranes for separating CO₂ from CH₄ and N₂ gases. Gas permeability tests conducted at 2 bar pressure and 30 °C compared pure membranes with membranes enhanced by 10 wt.% of the two-component DES and 10 wt.% of the three-component DES.
Results:
Results showed that the CO₂ permeability increased from 3.77 barrer for the pure membrane to 4.96 barrer for the 10 wt.% DES two-component membrane, and to 7.101 barrer for the 10 wt.% DES-DBU three-component membrane. The CO₂/N₂ and CO₂/CH₄ selectivities improved from 20.32 and 11.36 for the pure membrane to 38.56 and 13.77 for the DES two-component membrane, and to 40.68 and 14.32 for DES-DBU three-component membrane, respectively. Moreover, with an increase in feed pressure from 2 bar to 6 and 10 bar, the membrane performance improved. At 10 bar, the CO₂ permeability for the 10 wt.% DES three-component membrane increased to 16.28 barrer, while the CO₂/N₂ and CO₂/CH₄ selectivities rose to 56.13 and 20.60, respectively. Since the DES-DBU three-component membrane showed better performance than the DES two-component membrane and the pure membrane, various weight percentages of this composition were used to further enhance the Pebax polymer membrane. The results indicated that the membrane containing 20 wt.% of the DES-DBU three-component exhibited the best performance among all tested membranes. At 2 bar pressure and 30 °C, this membrane increased CO₂ permeability to 13.88 barrer and CO₂/N₂ and CO₂/CH₄ selectivities to 51.46 and 18.80, respectively. Furthermore, at 10 bar pressure, the CO₂ permeability reached 21.25 barrer, while the CO₂/N₂ and CO₂/CH₄ selectivities improved to 40.66 and 60.25, respectively. Ultimately, this membrane, compared to other studies, has successfully surpassed the Robeson limit, demonstrating its high potential for applications related to CO₂ gas separation.

Abstract Research Subject: Carbon dioxide (CO₂) pollution represents a major environmental challenge in contemporary society, primarily driven by industrial expansion. A notable modern approach for CO₂ separation involves the use of polymer membranes, with poly (ether-block-amide) (Pebax) recognized as a prominent industrial membrane in this field. However, this type of membrane is constrained by the permeability–selectivity trade-off, which hinders its broader application in industrial processes. One strategy to overcome this limitation is the incorporation of various functional compounds into Pebax.
Research Approach: This study selected phenol—characterized by its hydroxyl functional group—as a filler, and prepared Pebax membranes with varying phenol concentrations using advanced molecular simulation techniques. Molecular Dynamics (MD) and Grand Canonical Monte Carlo (GCMC) methods were employed to evaluate both the structural properties and gas separation performance of the membranes. Initially, structural properties—including fractional free volume (FFV), density, and polymer chain mobility—were analyzed, followed by assessments of functional properties such as diffusion and solubility coefficients.
Main Results: The incorporation of phenol led to an increase in the membranes' fractional free volume (FFV). Radial distribution function (RDF) analysis revealed that the interaction between CO₂ and phenol molecules was stronger than that between CO₂ and Pebax polymer chains. Furthermore, the results indicated that phenol increased the CO₂ diffusion coefficient by a factor of 5.5 and the solubility coefficient by 1.3 times compared to the pure Pebax membrane, due to Lewis acid–base and π-quadrupolar interactions. Analysis of CO₂ permeability and CO₂/N₂ selectivity in the simulated membranes showed that increasing the phenol content led to higher CO₂ permeability but a continuous decrease in CO₂/N₂ selectivity.

Abstract Research Subject: The flow of two immiscible liquids has garnered significant interest over the past few decades due to its relevance in various industrial applications, including chemical, petrochemical, food, and other process industries. It is particularly encountered in the water-lubricated transport of high-viscosity oil through pipelines. One of the simplest methods for studying the mass transfer coefficient in a liquid–liquid system involves a single droplet rising through a second, stationary phase. While this approach is well understood for nearly spherical droplets without surface turbulence or oscillations, it remains complex for ellipsoidal droplets exhibiting oscillatory motion, particularly in systems characterized by low interfacial tension.
Research Approach: This study investigates the effect of mass transfer on the velocity and shape of droplets in a chemical system composed of normal butanol, succinic acid, and water. Several variables are explored, including the dispersed phase flow rate, droplet size, and succinic acid concentration within the dispersed phase. Experiments were carried out using the single-drop method in an extraction column, employing normal butanol droplets with diameters ranging from 0.3 mm to 1.3 mm and Reynolds numbers below 300.
Main Results: The results reveal that mass transfer significantly influences droplet velocity, delaying the attainment of terminal velocity. Despite deformation, the droplet regime remains unchanged. The low interfacial tension in the system leads to the formation of oval-shaped droplets, with aspect ratios decreasing to as low as 0.4. However, under mass transfer conditions, droplets become wider and more spherical, resulting in a 50% increase in aspect ratio at the highest succinic acid concentration and with the largest nozzle size, compared to conditions without mass transfer. Terminal velocity and droplet deformation were further analyzed using dimensionless numbers, including the Reynolds number, Eötvös number, and Weber number.

Abstract The depletion of fossil energy resources and the emission of greenhouse gases are among the key factors driving attention toward renewable energies. Hydrogen storage, as an energy carrier, is considered one of the promising methods for sustainable utilization of these resources. In underground hydrogen storage (UHS), a portion of the gas remains unrecovered due to insufficient production pressure and is retained as cushion gas. To minimize hydrogen loss, it is proposed to replace hydrogen with more cost-effective gases, such as methane, nitrogen, or carbon dioxide, as the cushion gas. This study provides a comprehensive assessment of various cushion gases and the parameters influencing hydrogen storage in their presence, aiming to propose strategies for optimizing this process. In this study, over 300 scientific papers were reviewed, among which 80 articles were selected as the primary sources related to the underground storage process of hydrogen gas and other gases in the presence of cushion gas, while an additional 82 articles were reviewed as complementary references. These papers were categorized into three groups: the impact of cushion gas properties, reservoir properties, and operational parameters. The content was summarized and presented coherently, providing a comprehensive foundation for analyzing hydrogen storage in the presence of cushion gas. The results indicated that using gases such as methane, nitrogen, and carbon dioxide as cushion gas could significantly contribute to the economic aspects of UHS by reducing the amount of trapped hydrogen in the reservoir. The density and viscosity of the cushion gas play an important role in UHS. Nitrogen gas, due to its favorable physical properties, is a superior option for injection as it reduces the risk of phenomena such as gravitational segregation and fingering. In contrast, carbon dioxide, due to its solubility in formation water and high compressibility, requires the injection of larger volumes to achieve the desired reservoir pressure. Additionally, reduction in pressure and increase in temperature, porosity, and permeability lead to a decrease in hydrogen purity. Furthermore, simulations show that injecting the appropriate cushion gas and increasing the reservoir's recovery factor before starting hydrogen storage can help improve hydrogen purity and recovery.

Abstract Research subject: Research subject: Incomplete combustion of methane in natural gas vehicles, gas turbines, and other sources releases environmental pollutants, including unburned methane. Thus, employment of processes that provide complete combustion of methane at low temperatures is necessary. Lean catalytic methane combustion is an efficient process for controlling environmental pollutants while utilizing methane as a fossil (or synthetic) fuel source. Despite extensive research, the development of catalysts with high activity, thermal stability, and low light-off temperature remains a significant challenge in this field.

Research approach: In this study, manganese-iron mixed oxide catalysts and Ce-promoted manganese-iron mixed oxide catalysts were evaluated for lean methane combustion under the following conditions: an oxygen-to-methane ratio of 6:1 and temperatures ranging from 200°C to 550°C in 50°C increments. The manganese-iron mixed oxide catalyst was synthesized using a surfactant-assisted co-precipitation technique, while the Ce-promoted manganese-iron mixed oxide catalyst was prepared via a wet impregnation method.
Main results: The Mn-Fe catalyst showed great catalytic activity in lean methane combustion. The temperatures corresponding to 10%, 50%, and 90% methane conversion (light-off temperatures) for the Mn-Fe catalyst were 305°C, 333°C, and 437°C, respectively. The high catalytic activity of the Mn-Fe catalyst was attributed to its high BET surface area (59.9 m2·g-1), the redox properties of the mixed oxide, and the oxygen storage capacity of manganese oxide. The Ce-promoted Mn-Fe catalysts exhibited relatively higher catalytic activity compared to the unpromoted catalyst in lean methane combustion. 90% methane conversion was achieved at 421°C (T90) for the promoted catalyst, while no significant changes were observed in the temperatures corresponding to 10% and 50% methane conversion. The addition of Ce as a promoter enhanced the catalyst's stability at 500°C after 5 hours on stream. The promoted catalyst exhibited no decrease in catalytic activity, whereas the unpromoted catalyst showed a decrease of less than 2% in catalytic activity.