مجله فرآیند نو
پیاپی 80 (زمستان 1401)

In this research, the application of adsorption isotherm, kinetic and thermodynamic models in a rotating disk reactor covered with graphene nanoparticles designed to remove aromatic compounds from the wastewater of the refinery located in Sari oil facilities and as a result reducing the chemical oxygen demand (COD) of the wastewater was investigated. Langmuir-Freundlich thermocouple was used to investigate the removal process. Also, adsorption kinetics were investigated by pseudo-first-order, pseudo-second-order and intermolecular diffusion models. The thermodynamics of adsorption was studied by Vant Hoff relation and its results were analyzed. Also, the effect of change in effluent concentration (70,100,150 mg/L) and temperature (20, 30 and 40˚C) and the number of discs containing graphene on the COD removal rate of the effluent was investigated. The results of the experiments showed that the rate of absorption and reduction of effluent COD increased with the increase of initial concentration and the temperature of the process and under optimal conditions was equal to 66%. From the examination of the equations, the applicability of two isothermal equations in the form of Freundlich Langmuir and models Kinetics were determined as pseudo-second order > intermolecular diffusion > pseudo-first order. From the analysis of the data, it was found that increasing the concentration and efficiency of the adsorbent has a positive effect and improves COD removal. At high concentrations, the ratio of effluent to graphene active surfaces and concentration gradients were the leading factors of absorption. The COD reduction percentages for concentrations of 70, 100, and 150 mg/L were 48%, 62%, and 73%, respectively.

Heavy crude oil cracking units (hydrocracker) and crude oil desulfurization (hydrotreater) are the two most important hydrogen-consuming units in the refinery. Affected parameters such as hydrogen consuming units and environmental rules increase the necessity of optimization the hydrogen network in the refinery. In this article, we intend to obtain the optimal hydrogen network structure in Abadan Refinery using the superstructure method. The superstructure method includes a mathematical model that is able to provide the hydrogen necessity by consumers and design the optimal hydrogen network with the lowest cost. The results of optimization show the hydrogen from RPS CRU and COLD-SEP CRU streams, which were sent to the fuel system before optimization can be recovered and reused in the network. RPS CRU and COLD-SEP CRU flow rates of 5000 and 3600 (kg/h), respectively, with relatively high purity of hydrogen, can be sent to the PSA purifier for the recovery. In addition, regarding to the recovery there is no necessity to utilize the hydrogen production unit (U-57) and it will be taken out of service, and as a result, the purchase cost of the hydrogen production unit will be removed from the network.

The increase in CO2 emissions is the main cause of global warming and causes adverse environmental challenges. Based on this, finding ways to convert CO2 into useful products can help reduce the harmful environmental effects of this substance on the one hand, and increase the economic efficiency of the process to produce valuable products on the other hand. Thus, the sources of CO2 emissions were investigated first, and then the methods of separating of CO2 were described. Also, the use cases of CO2 in various industries were discussed. The results showed that membrane contactors are one of the effective technologies in CO2 absorption. Also, the product which currently produced in large quantities from CO2 is urea. Then there are some discussions about urea. The results of studies showed that membrane contactors are one of the effective technologies in CO2 absorption, so some investigations were carried out in this field.

In this paper, the motion of water droplets inside a cathode gas channel of a polymer membrane fuel cell with transverse channel blocking is investigated numerically, biphasically, and two-dimensionally.24 different blocked geometries are studied and the effect of the different block length (Wr) and the position of the block across the channel (λ) upon velocity and pressure contours, the shape of streamlines and droplet deformation is investigated and droplet discharge time, instant pressure drop, mean pressure drop, and instant and mean water coverage ratio are calculated. The results show that the channel becomes blocked and clogged for some geometries and in other cases where the droplet crosses the barrier, the discharge time decreases and the instant and average pressure drop and water coverage ratio increase by placing the barrier. According to the obtained results, the greatest decrease in discharge time (if there is no restriction in pressure supply) is for Wr=1.66 and λ=0.3. Also, the lowest instant pressure drop and water coverage ratio occur for Wr=0.66 and λ=0.3.

Investigating methods to remove sulfur compounds from fuel is one of the most important and vital issues in the oil industry. Adsorptive desulfurization is known as one of the most promising desulfurization methods due to its low energy consumption. Metal-organic frameworks are a new family of porous materials with tunable structure and function. High specific surface area and porosity, adjustable pore size, and most importantly, high selectivity of metal-organic frameworks towards sulfur compounds, are among the features that distinguish this adsorbent from other adsorbents such as metal oxides, zeolites and carbon compounds, and they show higher adsorption capacities than other adsorbents due to the proper interaction with sulfur compounds. The dominant mechanisms in the adsorptive desulfurization process over metal-organic frameworks are π complexation, acid-base interaction, direct sulfur-metal interaction, and van der Waals forces. In this study, the application and mechanisms of MOF in adsorptive desulfurization was investigated.

The purpose of the current research was to know the impact of sustainability on the energy consumption of Asalouye plants. Studies conducted in the world regarding similar issues, especially sustainable development and supply chain, have been conducted in the general aspect of the case, based on existing articles, but in this article, the issue has been tried in the form of a research and case study, taking into account the situation Geographically, technologically and also culturally, to be examined and compared. Considering that in the studies, the stability of the supply chain can also prevent energy waste, in this research, the issue of what effect the stability of the supply chain can have on energy efficiency in Asalouye refineries has been addressed. The investigated population of the statistical population of this research includes the managers and employees of Asalouye refinery centers. The number of managers and centers of single-phase, two-phase and three-phase refinery centers that are in the operational phase has been 15 refineries, and the number of operational experts and specialists in each of these types of refineries has been evaluated as 120 people. According to the size of the statistical population, the sampling method used and based on the Morgan table, 92 people have been considered as a sample. The investigated tool is the sustainable supply questionnaire, which includes 50 questions on the economic, social and environmental scales, and the researcher-made energy efficiency questionnaire, which has 8 questions designed on a five-point Likert scale. Data analysis was done in SPSS21 software. Finally, after conducting the mentioned analyzes and surveys and obtaining results in each of the sources of sustainability in providing security (economic, social and environmental), the amount of influence on the energy efficiency of Assalouye refineries, according to the presented tables. The relevant parts were obtained.