مجله فرآیند نو
پیاپی 82 (تابستان 1402)

In this article, the CFD simulation of the medium pressure flare of South Pars 5th Refinery has been carried out in industrial dimensions in order to investigate the effect of the flare tip geometry on the flare combustion characteristics. CFD model was developed. In order to avoid numerical errors proper meshing was done. The results of CFD simulation show that in the operational conditions, the increase in the temperature of the Flare type body due to the impact of the flame is negligible, so its performance is suitable with the current amount of sweeping gas. Therefore, it is not possible to further reduce the gas sent to the MP flare because the flame may be drawn into the flare network, the temperature of the flare tip surface and the wind shield may increase, which in the long run will cause the flare tip surface to be destroyed.

In the challenge of chemical production, management will be successful if it has production waste and by-products in terms of mass and finance. The new method of material flow costing (MFCA) is using green productivity tools, which increases productivity with a mass and financial approach and increasing efficiency. This method saves money by initially identifying and then providing a scientific and practical way to prevent material loss (waste), energy, costs and CO2 emissions. To achieve this goal, MFCA can be used to calculate the true costs of losses (hidden costs). Therefore, the purpose of this study is the production wastes in the olefin unit of a petrochemical company in the south of Iran and the cost characteristics of these wastes using the MFCA tool. Also, methodological solutions to reduce these wastes and increase productivity in this industrial unit have been presented. Based on the application of productivity improvement strategies, a 40% reduction in coke waste and a 10% increase in ethylene production are predicted in the process.

Today, the drawbacks of the hydrodesulfurization process have led to the development of new methods such as adsorptive desulfurization (ADS), extraction, oxidation, etc. Unlike the hydrodesulfurization method, ADS has the ability to remove resistant sulfur compounds such as DBT and its derivatives without the need for expensive and risky hydrogen and under low operating conditions (temperature and pressure). In this article, in addition to the comparison of modern desulfurization methods, among the solid adsorbents used in the ADS process, the performance of porous carbon adsorbents is investigated due to their unique characteristics such as high surface area and porosity, easy modification of physical-chemical properties and the cost is affordable and has been paid. Also, for a better understanding of the process, the effective process parameters, kinetics and thermodynamics and various adsorption mechanisms in the ADS process by carbon materials have been investigated. And finally, various methods of recovery of carbon adsorbents are introduced and the challenges of advancing the ADS process are mentioned.

Heavy metals are extremely harmful environmental pollutants due to their toxicity, non-biodegradability and environmental accumulation that can affect people and the environment. Microbial fuel cells are a type of bioelectrochemical approach in which bacterial species remove organic pollutants and metal ions from synthetic and industrial wastewater and simultaneously generate electricity. Currently, the real applications of these devices in the world are limited due to the low level of production density. According to the investigations carried out in this article in recent years, microbial fuel cells have been used as one of the ways to remove heavy metals from industrial effluents, and 10 to 100% removal rates were achieved for metals such as gold, chromium, copper, lead, cadmium, mercury, zinc, arsenic and nickel. Also, the parameters affecting the amount of removal were evaluated in these studies, and the optimal conditions are in most cases in the range of neutral pH and in some cases in pH=2, at a temperature of 22 to 35 0C and an external resistance of 200 to 1000 ohms.

Conventional steels and their alloys are not able to withstand high temperature corrosion in thermal power plant boilers. For boiler fireside components, issues of concern include erosion and corrosion in operating environments. Different thermal spray coating techniques have been developed to spray different types of coatings on boiler steels. Advances in thermal spraying techniques have led to the development of coatings with corrosion resistance properties. In this article, firstly, the introduction and the necessity of applying the coating used for boiler equipment is stated, then the studies carried out until today about the performance, developments and applications of thermal spray coatings for resistance to high temperature corrosion were examined, and finally a case study of using this coating in a power plant was mentioned. Among the types of coatings, Ni-20Cr alloy and their composite with carbide compounds is the most optimal coating with good performance in all types of boilers.

Shell & tube heat exchangers are known as one of the most important devices in oil, gas, and energy industries. Alongside their design, their maintenance would also be of prime importance when they are prone to mineral scale formation. According to the field reports, the mineral scaling can be formed in heat exchangers due to the presence of fluid precursors at different operating conditions as well heat transfer surface conditions. Thus, in-depth knowledge of the best management methods to control scale formation in heat exchangers is indispensable for engineers. In this paper, various methods of controlling mineral scale formation, including removal and inhibition, i.e., conventional physical and chemical methods, and ultrasonic technology have been examined for an industrial case study. Moreover, several statistics from the field reports have been examined to prove that the utilization ultrasonic would clean the exchanger under study. The results show that scale management especially the use of ultrasonic technology would lead to an increase in the efficiency of heat exchangers as well as a significant reduction in operating costs.