مجله فرآیند نو
پیاپی 77 (بهار 1401)

In this study, a new composite adsorbent based on dolomite mineral, coated with chitosan and graphene oxide was fabricated and used for removal of methylene blue (MB) from water. The effects of time, initial MB concentration, pH and temperature on the adsorption capacity of the fabricated composite adsorbent in the removal of MB as a cationic dye were investigated. The obtained results were analyzed by Freundlich and Langmuir isotherm models as well as pseudo first and second order kinetic models. The results of adsorption experiments showed that the fabricated composite adsorbent for removing MB follows the Langmuir adsorption isotherm model and the pseudo second order kinetic model. According to the Langmuir isotherm, the maximum monolayer adsorption capacity of MB on the surface of the composite adsorbent is equal to 3.746 mg/g. This adsorbent has a higher adsorption capacity at high temperatures and alkaline pHs.

In this study, a solid oxide fuel cell fed with synthesis gas derived from industrial waste water was combined with a Rankine power generation cycle was analyzed and investigated using thermodynamic relationships. First, the solid oxide fuel cell was independently simulated and the quantities such as output voltage, current density and output power of the fuel cell were calculated. Then, the power cycle that equipped with a gas turbine combined with a solid oxide fuel cell was investigated according to the output results of the fuel cell simulation using thermodynamic analysis. In current study, fuel cell output voltage as a function of current density was reported, and the effect of temperature and pressure increasing on output fuel cell voltage was reported. The analysis of this system showed that with the increase in temperature and pressure, the output voltage of the solid oxide fuel cell increased. The varation in the output power of the fuel cell against the current density at three operating temperatures of 1073, 1173 and 1273 K were also calculated, the results showed that the power of the fuel cell increases with the increase in temperature. Also, the total efficiency of the hybrid system by increasing in fuel cell operating temperature increased.

This study investigates the application of biochar from the macroalgae pyrolysis of Gracylaria gracilis as catalyst support for the production of mid-distillation fuels. Macroalgae were pyrolyzed at 550 °C, and the resulting products were evaluated. The major product of the pyrolysis was biochar (40.1%). The gaseous product mostly contained carbon dioxide (51.9%) and hydrogen (26.3%), and the liquid product mainly contained oxygenate and nitrogenate compounds. The abtained biochar was activated and impregnated with 15% cobalt and then used as a catalyst in the Fisher-Tropesh process under conditions of syngas flow of 45 ml/min (H2/CO = 2), 18 bar pressure and temperature of 220 °C. The results showed that carbon monoxide conversion was 64.2%, and the highest product selectivity was for heavy hydrocarbons (74%), while the selectivity of carbon dioxide as a by-product was 2.3%. Catalyst characterization was performed by BET, XRD, TPR, TGA and TEM methods.

One of the main processes of producing light olefins is catalytic cracking. The commercial catalysts used in this process are zeolite catalysts. According to the operating conditions of the reaction, the used catalysts are deactivated after some time. One of the major challenges in this process is finding an optimal catalyst that, in addition to proper performance, has high selectivity over propylene. In order to reduce the penetration resistance of materials in zeolite micropores and easier access of materials to active sites and to create mesopores, numerous modifications were made using pre- and post-synthesis methods (synthesis of zeolite with special morphology, crystal size reduction, dealumination and desilication) has been done. These modifications have increased the lifetime and improved catalyst performance. In this research, the recent developments about zeolite catalysts and methods of improving the performance of ZSM-5 zeolite catalysts in the catalytic cracking process of normal hexane have been described.

One of the most important strategies of any country for the integrated and comprehensive development of all regions is the development of energy infrastructure with the aim of expanding industries, creating employment, providing public services and preventing the migration of residents of border areas. Therefore, reducing the vulnerability of oil and gas infrastructures is of great importance due to their important role in life, because even a short interruption in the provision of oil and gas infrastructure services will have irreparable effects on the various activities of the country in critical conditions where the country is facing shortages, is enters. In this article, after reviewing the different methods of risk assessment using FEMA's applied method, first the oil and gas assets of the border provinces were screened, then based on the threats based on the identification and evaluation of the vulnerabilities, and the risk of each asset was calculated and at the end with In order to protect the infrastructure, solutions are provided to reduce the risk in the oil and gas infrastructures of the border provinces.

This article is written with the aim of investigating the industrial cleaning methods of crude oil and products storage tanks and identifying the most efficient, safe and economical ones. For this perpose, the types of cleaning and recycling methods for oil sludge describe along with their advantages and disadvantages, then three widely used manual, automatic, and robotic methods discusse. The results show that the automatic cleaning system with powerful pumps is the fastest cleaning system, while the robotic method, where the presence of people inside the tank is not required at every stage, is the safest system. In terms of cleaning costs and environmental impact, automatic and robotic systems may be more expensive than manual methods, but due to the closed cleaning cycle, the ability to recover up to 95% of the sludge, income from the sale of recycle materials, they are the most cost-effective and environmentally friendly.