مجله فرآیند نو
پیاپی 76 (زمستان 1400)

Pipeline is the most common method for transmission of natural gas. One of the most expensive stages of natural gas transmission are pressure boosting stations. To reduce the cost of the pressure boosting stations, natural gas transmission in the dense phase state was proposed. In this study, the fifth national pipeline was investigated in both dense phase and normal conditions. The results showed that when the natural gas is transmitted in a dense phase state, the gas velocity will be 4 times slower than normal condition. The pressure drop in the pipeline was reduced four times compared with normal condition. Due to the lower pressure drop in the dense phase state, the number of pressure boosting stations were reduced from four to zero. Also, in the dense phase state, at the end of the pipeline 379.5 MW energy could be recovered.

Biological desulfurization by microorganis msisasuit able method to remove sulfur containing compounds from fossil fuels.The aim of the present research was to introduce indigenous microorganisms with the ability to biologically remove of sulfur.In order to isolating native microorganisms, oil contaminated soil samples taken from Abadan oil refinery were transferred to the microbiology laboratory.Enrichment of oil-contaminated soil samples was performed during 4 subcultivations in BSM medium with 0.5 mM DBT as the only source of sulfur during which 20 bacterial isolates were obtained.Superior isolates were selected based on growth rate and turbidity caused by the consumption of DBT.In order to investigate the possible metabolic pathway of desulfurization in isolates, the most common metabolic pathway of desulfurization, i.e. 4S pathway, was tracked through the Gibbs assay, and the production of blue color could confirm the existence of this pathway in microorganisms.GC-MS method was used to check the amount of dibenzothiophene reduction.Isolates BDS9, BDS18 and BDS37 were able to remove 95.7%, 95.5% and 86.5% of DBT over a period of 72 hours, respectively.

In this study, a new composite adsorbent based on diatomite mineral, coated with chitosan and functionalized carbon nanotubes was fabricated and used to remove methylene blue dye from water. The effects of initial dye concentration, pH and temperature on the adsorption capacity of the fabricated adsorbent in the removal of methylene blue as a cationic dye were investigated. The obtained results were analyzed by Freundlich and Langmuir isotherm models as well as first and second order kinetic models. The results of adsorption experiments showed that the fabricated composite adsorbent for removing methylene blue follows both the Freundlich and Langmuir adsorption isotherm models and the second order kinetic model and its equilibrium adsorption capacity for methylene blue solution with concentration of 50 ppm equals to 7.98 mg/g. This adsorbent has a higher adsorption capacity at high temperatures and alkaline pHs.

In sulfur recycling units (SRU), due to environmental considerations, increasing efficiency and reducing pollutants have been prioritized, and the most important factors affecting them were process design and the use of appropriate catalysts. In this study, in order to increase the process efficiency, feedback and feedforward control loops along with high percentage (85%) TiO2 catalyst have been used and economic aspects were investigated. The results obtained from SRU Unit 4 of Shahid Hasheminejad Refinery show that the new catalyst increases the temperature difference between different parts of the substrate compared to the usual catalyst and shows an increase in hydrolysis of sulfur compounds and conversion efficiency. The optimal case and the lowest error are created in the case of simultaneous use of both control loops. According to economic estimates, the return on investment is a maximum of one month, and as a result, this plan is economically viable.

Nowadays with the advancement of industry, more greenhouse gases specially CO2 are being emitted to the atmosphere, therefore it leads to some massive environmental issues such as global warming. In addition to the harmful environmental effects of CO2, presence of this gas with H2S in natural gas contribute to low heating value and furthermore corrosion of process equipment due to the high acidity of these gases. One of the effective industrial methods is utilizing amine and ammonia solutions for absorbing and carbon capturing. however, due to its drawbacks and also advantages of adsorption process specially zeolite adsorbents, adsorption has drawn researchers’ attention. In this context, will be discussed about some zeolite adsorbents which are used for CO2 and H2S adsorption and discussion about mechanisms of H2S adsorption on FAU, LTA, and 13X zeolites.

Innovation in the oil refining industry has led to the creation of a new term called petro-refinery. Petro-refineries are the evolution of the oil refining industry against external factors of "technology push" and "market needs". In this paper, the creation of petro-refinery innovation from the perspective of these factors is described. The main factors of market demand at the international level, including energy transition requirements,, reduction of fossil fuel consumption and further added value of petrochemicals production, have been studied in detail. The role of high energy demand in changing the nature of the refining industry from a profit-oriented industry to a fuel-oriented industry has also been considered. From the perspective of "technology push", the technologies developed in this field show that these technologies will play a key role in the future of the petro-refinery industry.