5 research outputs found
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Optimal Design and Operation of an Industrial Three Phase Reactor for the Oxidation of Phenol
YesAmong several treatment methods Catalytic Wet Air Oxidation (CWAO) treatment is considered as a useful and powerful method for removing phenol from waste waters. In this work, mathematical model of a trickle bed reactor (TBR) undergoing CWAO of phenol is developed and the best kinetic parameters of the relevant reaction are estimated based on experimental data (from the literature) using parameter estimation technique. The validated model is then utilized for further simulation and optimization of the process. Finally, the TBR is scaled up to predict the behavior of CWAO of phenol in industrial reactors. The optimal operating conditions based on maximum conversion and minimum cost in addition to the optimal distribution of the catalyst bed is considered in scaling up and the optimal ratio of the reactor length to reactor diameter is calculated with taking into account the hydrodynamic factors (radial and axial concentration and temperature distribution)
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Significant cost and energy savings opportunities in industrial three phase reactor for phenol oxidation
YesEnergy saving is an important consideration in process design for low cost sustainable production with reduced environmental impacts (carbon footprint). In our earlier laboratory scale pilot plant study of catalytic wet air oxidation (CWAO) of phenol (a typical compound found in wastewater), the energy recovery was not an issue due to small amount of energy usage. However, this cannot be ignored for a large scale reactor operating around 140–160 °C due to high total energy requirement. In this work, energy savings in a large scale CWAO process is explored. The hot and cold streams of the process are paired up using 3 heat exchangers recovering significant amount of energy from the hot streams to be re-used in the process leading to over 40% less external energy consumption. In addition, overall cost (capital and operating) savings of the proposed process is more than 20% compared to that without energy recovery option
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Improvement of fuel quality by oxidative desulfurization: Design of synthetic catalyst for the process
YesThe present study explored a novel oxidative desulfurization (ODS) method of light gas oil fuel, which combines a catalytic oxidation step of the dibenzothiophene compound directly in the presence of molecular air as oxidant to obtain high quality fuel for light gas oil.
In chemical industries and industrial research, catalysis play a significant role. Heightened concerns for cleaner air together with stricter environmental legislations on sulphur content in addition to fulfill economic have created a driving force for the improvement of more efficient technologies and motivating an intensive research on new oxidative catalysts. As the lower quality fuel becomes more abundant, additional challenges arise such as more severe operation conditions leading to higher corrosion of the refinery installations, catalyst deactivation and poisoning. Therefore, among the technologies to face these challenges is to develop catalysts that can be applied economically under moderate conditions.
The objective of this work is to design a suitable synthetic catalyst for oxidative desulfurization (ODS) of light gas oil (LGO) containing model sulphur compound (dibenzothiophene (DBT)) using air as oxidant and operating under different but moderate operating conditions. The impregnation method is used to characterize two homemade catalysts, cobalt oxide (Co3O4/γ-Al2O3) and manganese oxide (MnO2/γ-Al2O3). The prepared catalysts showed that the manganese oxide has a good impregnation (MnO2=13%), good pore size distribution and larger surface area. A set of experiments related to ODS of dibenzothiophene has been carried out in a continuous flow isothermal trickle bed reactor using light gas oil as a feedstock utilizing both catalysts prepared in-house. At constant pressure of 2 bar and with different initial concentration of sulphur within dibenzothiophene, the temperature of the process was varied from 403K to 473K and the liquid hourly space velocity from(LHSV) was varied from 1 to 3 hr-1. The results showed that an increase in reaction temperature and decreasing in LHSV, higher conversion was obtained.
Although both catalysts showed excellent catalytic performance on the removal of molecule sulphur compound from light gas oil, the catalyst MnO2 catalyst exhibited higher conversion than Co3O4 catalyst at the same process operating conditions
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From agro-waste to encapsulated carbon catalyst for improving stability of naphtha desulfurization
NoThe deactivation of the oxidative desulfurization (ODS) catalysts is a challenge and is a major concern in industrial catalytic processes. In this work, an activated carbon (AC) was prepared from agricultural waste and modified to withstand the ODS activity loss over time. The AC was impregnated with manganese and coated with aluminum oxide to prolong the activity lifetime. The catalysts were characterized by nitrogen adsorption-desorption, scanning electron microscope, energy dispersive X-ray, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and transition electron microscope (TEM). The BET surface areas of the examined AC materials were 814.48 m2/g, 784.76 m2/g, and 755.03 m2/g for the AC, Mn/AC, and coated Mn/AC catalysts, respectively with a dominance of microporous pore size. The TGA showed that the coating layer retards the degradation of the active metal and suppresses phase transitions. XRD showed no change in the structure of the catalyst with a coating layer, and from the TEM analysis, the coating layer thickness was 3.6 nm. The kinetics of the ODS catalysts were investigated. It was shown that the ODS reaction follows the first-order kinetics and is not influenced by the coating layer. The activity decay was also investigated. It is found that the activation energy of the deactivation reaction over the coated catalyst was higher than the uncoated catalyst