Chemical Engineering
behrouz Bayati; pardis morshedi; Akbar Falahi; Towan Kikhavandi
Abstract
HThe formation of heat stable salts, such as acetate, formate, oxalate, and thiosulfate, in gas sweetening units creates various issues including corrosion, high foaming, and a reduction in unit efficiency. This research aimed to investigate the elimination of heat stable salts using an anion resin. ...
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HThe formation of heat stable salts, such as acetate, formate, oxalate, and thiosulfate, in gas sweetening units creates various issues including corrosion, high foaming, and a reduction in unit efficiency. This research aimed to investigate the elimination of heat stable salts using an anion resin. The findings indicate that it is feasible to remove approximately 85% of acetate anion salt from an amine solution at solution-to-resin ratio of 30. Two adsorption models, Langmuir and Freundlich, were employed to analyze the equilibrium adsorption of acetate anion salt. The results indicate that the Langmuir adsorption isotherm aligns more closely with the data obtained from the acetate anion ion exchange process with the resin. Furthermore, it was determined that the maximum adsorption capacity for acetate onto the resin is 15 mg/g at a temperature of 25°C. The impact of contact time during the adsorption process was examined using quasi-first-order and quasi-second-order kinetic models, as well as an intra-particle model. The results indicated that the quasi-first-order kinetic model provided the best fit to the data, and equilibrium adsorption was achieved after approximately 70 minutes. Thermodynamic parameters were also investigated, revealing a ΔH value of -12.7370 kJ/mol, indicating an exothermic adsorption process. Based on the conducted studies, the utilization of the selected resin appears to be a suitable option for the removal of heat stable salts.
Chemical Engineering
Erfan Tooraji; Ahad Ghaemi
Abstract
Separation of nitrogen from a gaseous mixture is required for many industrial processes. In this study, the adsorption of nitrogen on zeolite 4A was investigated in terms of different adsorption isotherm models and kinetics. An increase in the initial pressure from 1 to 9 bar increases the amount of ...
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Separation of nitrogen from a gaseous mixture is required for many industrial processes. In this study, the adsorption of nitrogen on zeolite 4A was investigated in terms of different adsorption isotherm models and kinetics. An increase in the initial pressure from 1 to 9 bar increases the amount of adsorbed nitrogen from 6.730 to 376.030 mg/(g adsorbent). The amount of adsorbed nitrogen increased from 7.321 to 40.594 mg/(g adsorbent) by raising the temperature from 298 to 333 K at a pressure equal to one bar; however, it then dropped to 15.767 mg/(g adsorbent) when temperature decreased to 353 K. Increasing the amount of the adsorbent from 1 to 4 g decreased the specific adsorption from 67.565 to 21.008 mg/(g adsorbent) at a temperature of 298 K and a pressure of 3 bar. Furthermore, it was found that the nitrogen adsorption experimental equilibrium data are consistent with Sips and Langmuir-Freundlich models. The highest overlap was achieved through second order and Ritchie’s models.
Petroleum Engineering – Production
Hadi Bagherzadeh; Zahra Mansourpour; Bahram Dabir
Abstract
In the current study, the kinetics of asphaltene particle flocculation is investigated under a shear flow through numerical simulation. The discrete element method (DEM) is coupled with computational fluid dynamics (CFD) to model the agglomeration and fragmentation processes. In addition, a coalescence ...
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In the current study, the kinetics of asphaltene particle flocculation is investigated under a shear flow through numerical simulation. The discrete element method (DEM) is coupled with computational fluid dynamics (CFD) to model the agglomeration and fragmentation processes. In addition, a coalescence model is proposed to consider the attachment of colliding particles. The changes in mean asphaltene floc size, the particle size distribution (PSD) of asphaltene flocs over simulation time, and the average fractal dimension are presented. Moreover, the effect of fluid velocity on the kinetics of asphaltene flocculation is examined. The mean asphaltene floc size increases exponentially at first, and then the growth slows; finally, it ceases due to the establishment of a dynamic equilibrium between the agglomeration and fragmentation processes. As expected, asphaltene PSD’s move from fine to coarse sizes during the simulation. Log-normal distribution matches the PSDs best, which is in agreement with the nature of asphaltene. As fluid velocity increases, the dynamic equilibrium is attained more rapidly at a smaller mean floc size and higher average fractal dimension; furthermore, PSDs shift to smaller asphaltene floc sizes. The obtained average fractal dimensions of the asphaltene flocs are in the range of 1.65 to 1.74, which is compatible with the values reported in the literature. Eventually, a semi-analytical model is utilized to fit the simulation results. It is found out that the semi-theoretical model is capable of predicting the evolution of asphaltene particle size appropriately.
Vahid Mohebbi; Reza Mosayebi Behbahani
Abstract
In this study, mass transfer coefficients (MTC’s) of natural gas components during hydrate formation are reported. This work is based on the assumption that the transport of gas molecules from gas phase to aqueous phase is dominant among other resistances. Several experiments were conducted on ...
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In this study, mass transfer coefficients (MTC’s) of natural gas components during hydrate formation are reported. This work is based on the assumption that the transport of gas molecules from gas phase to aqueous phase is dominant among other resistances. Several experiments were conducted on a mixture of natural gas at different pressures and temperatures and the consumed gas was monitored and measured over time. The driving force is the difference between the solubility of hydrate former components at operating pressure and the corresponding equilibrium pressure. It was found that MTC is a function of pressure and temperature during hydrate growth stage. Consequently, an equation was proposed to calculate the mass transfer coefficient based on the experimental data.
