Chemical Engineering
Gholamreza Roohollahi; Mohammadreza Ehsani
Abstract
Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating ...
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Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating 10 wt.% nickel on the supports, the precursor was decomposed at several temperatures of 500, 600, 700, and 800 °C in order to elucidate the effect of calcination temperature on the physical and chemical characteristics of Mg-Al mixed oxides and the ultimate catalytic performance of the synthesized catalysts in the combined steam and dry reforming (CSDRM). The catalyst the precursor of which was calcined at 700 °C shows an excellent nickel dispersion and the highest activity among the other samples. It also exhibits the most stable performance during the long-term 36-hour run with high resistance against coke formation in the harsh condition of CSDRM.
Chemical Engineering
Farshad Torabi Esfahani; Javad Ivakpour; Mohammadreza Ehsani
Abstract
In this work, new correlations are proposed to predict the products yield of delayed coking as a function of CCR and temperature based on the experimental results. For this purpose, selected Iranian vacuum residues with Conradson carbon residue (CCR) values between 13.40-22.19 wt.% were heated at a 10 ...
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In this work, new correlations are proposed to predict the products yield of delayed coking as a function of CCR and temperature based on the experimental results. For this purpose, selected Iranian vacuum residues with Conradson carbon residue (CCR) values between 13.40-22.19 wt.% were heated at a 10 °C/min heating rate and thermally cracked in a temperature range of 400-500 °C in a laboratory batch atmospheric delayed coking reactor for 2 hours. The amount of distillate (C5+-500 °C) and coke yield were measured in all the experiments, and the gas (C1-C4) product yield was calculated based on mass balance between products and feedstock in each experiment. According to the developed functions, products yield changes with CCR value linearly and is a power function of temperature. The further investigation of the results show that by a 1 wt.% increase in CCR value, the distillate yield decreases by about 2.1 wt.%, but the amount of coke and gas yields rise by 1.2 wt.% and 0.9 wt.% respectively.
Tahereh Asadi; Mohammadreza Ehsani
Abstract
Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped ...
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Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped bodies reduces their adsorption performance. In this work, Cu-BTC tablets provided by BASF are evaluated to perform CO2/CH4 separation through adsorption. The adsorption capacity of pure carbon dioxide from methane was measured in a magnetic suspension balance between temperatures of 308 and 373 K up to a pressure of 700 kPa. The evaluated material presents higher adsorption capacity than previously studied shaped samples with a carbon dioxide and methane adsorption capacity up to 3.07 and 0.63 mol/kg at 100 kPa and 308 K respectively. Moreover, the experimental data were fitted with the Langmuir model. Isosteric heats of adsorption were obtained to be 22.8 and 15.1 kJ/mol for CO2 and CH4 on Cu-BTC tablets respectively, which indicates a strong adsorption of carbon dioxide on these adsorbents. Also, single and binary breakthrough curves were measured in the same temperature range and atmospheric pressure by using Cu-BTC tablets as the adsorbent. The preferential adsorption capacity of CO2 on nanoporous copper trimesate (Cu-BTC) indicates that this material can be used for methane purification from natural gas.
