مجله فرآیند نو
پیاپی 75 (پاییز 1400)

Conversion of heavy residual oils like Mazut  is of great importance due to the decrease in local consumption and export following the legislation of strict environmental limitations. In this regard, catalytic conversion of Mazut in the presence of nickel and molybdenum supported on MAF-6 metal-organic framework is studied. MAF-6 was nominated as active phase carrier in heavy oil owing to its higher surface area, milder acidity and flexible framework compared to conventional industrial supports like Alumina and also very high hydrophobicity. Metal insertion was performed via in-situ method and influence of 0.7wt% of prepared catalyst on quality and quantity of upgraded liquid was investigated. Compared to the thermal upgrading, upgrading with nickel and molybdenum containing catalysts were accompanied with 52% and 37.5% more viscosity reduction, 3% and 11.4% higher asphaltene removal, increase in light and middle distillates content from 67.6% to 73.5% and 70.5% and more decrease in aromaticity, respectively.

Erosion occurs due to the transportation of very fine particles in fluid flow such as oil and gas pipelines, which could lead to serious damage to them. In this study, erosion phenomena is modeled using the COMSOL software. Three applied industrial models, namely Finnie, DNV and ECRC in turbulent fluid flow have been applied. The effects of fluid velocity including 5, 10 and 20 m/s, solid particles diameter including 120, 170 and 220 microns, and injecting sand flow rates including 0.3, 0.6 and 0.9 kg/h on the amount of erosion have been investigated. The three models show almost the same area in the external radius section of the elbow, as the region of most susceptible to erosion. The results show that increasing the fluid velocity, solid particles diameter and injection flow rate of solid particle boosts the erosion at the elbows.

In this paper, the integration of a biomass gasification process with a geothermal power plant is investigated. The purpose of this study is to enhance the effective power of the geothermal plant turbine by supersaturating the output steam from the geothermal well by using the excess heat of the biomass gasification process. In this regard, a geothermal power plant with a production capacity of 2.8 MW was selected as a case study and simulated in Aspen Plus software. Then a biomass gasification process was simulated using the binary fluid bed method in this software. Finally, a hybrid system including the geothermal power plant and the biomass gasification unit was designed and simulated. For this purpose, 3.9 kg/s saturated steam was extracted from the geothermal well and supersaturated by the excess heat from the gasification process with a biomass flow rate of 31950 kg/s. The amount of syngas produced in this process as a by-product is 34353.9 kg/hr. The results showed that geothermal process efficiency increased from 15.7% to 29.5% and production capacity under the same operating conditions increased from 2.8MW upgraded to 3.6 MW.

Nowadays Spinning Cone Columns (SCC) are facing widespread application in chemical industries. In this work, the pressure drop parameter of the air and water system inside the SCC tower at pilot scale have been investigated by using computational fluid dynamics and compared with experimental data.The model studied in this work consisted of two stages of the tower and the dry and the two-phase pressure drop at rotational speeds of 500, 1000 and 1500 rpm were obtained and the effect of rotational speed on the amount of pressure drop inside the tower has also been investigated. The average relative error in the case of dry pressure drop was 11% and for the two-phase pressure drop with the liquid flow rates of 0.6, 0.9 and 1.5 kg / min was 13%. The simulation results also show that as the rotational speed increases, the system pressure drop also increases.

Liquefied natural gas is obtained by reducing the temperature of natural gas to a temperature of -160, in this study, by using ASPEN HYSYS software, the PRICO liquefaction cycle, which includes two compressors and a heat exchanger, was simulated. The simulations were performed in two modes of high pressure (7945 Kpa) and low pressure of natural gas (2861 Kpa). The objective function was to minimize the specific energy consumption of the process. The energy consumption was 0.316 kWh / kgLNG, which showed a decrease of 22% compared to the reference value.
From Sensitivity analysis, it was concluded that the higher the molar flow rate of methane, ethane, propane and nitrogen in the refrigerant composition, the higher the specific energy consumption. In addition, it is better to have a high percentage of isopentane in the refrigerant to achieve the lowest specific energy consumption. In addition, the coefficient of performance was examined, which in the high pressure reached 3.12.

In this research, by the method of exergy analysis in the alkylation unit of phase 3 of the Abadan refinery, the possibility of replacing the adsorption cycle with the compression cycle has been investigated. After designing and simulating the cycles based on the results, chillers E-1, E-2, E-3, and E-4 were replaced with compression chillers C4, C3, IC4, and ISOMER in the designed absorption cycle. Also, C-14200compressors with a power consumption of 5537.30 kW and C-14200B with a power consumption of 4258.43 kW are not required. The end result of this research is that the designed adsorption cycle due to the presence of excess steam in the refinery easily provides the desired amount of cooling, which can be a good alternative to the existing compression cycle.