Study of mechanism and kinetic modeling of CO hydrogenation reaction over the impregnated Co‐Ni/Al₂O₃ catalyst

Abstract

An investigation of the kinetic and mechanism of CO hydrogenation reaction was performed on impregnated Co‐Ni/Al2O3. Determination of kinetic parameters from the experiments was carried out in a micro fixed‐bed reactor. Kinetic evaluations were performed under various operational conditions of T = 473–673 K, p = 1–14 bar, H2/CO = 1–3, and GHSV = 4,500 hr−1. Kinetic models and rate equations for CO consumption were obtained by using two main‐type rate equations of Langmuir‐Hinshelwood‐Hougen‐Watson (LHHW) and Eley‐Rideal (ER). Estimation of various kinetic parameters was performed using a nonlinear regression method. According to the obtained experimental results and using statistical criteria, one kinetic expression based on the LHHW mechanism (‐rCO = kp.bCO.PCO. bH2. PH2/[1+ bCO.PCO + bH2.PH2]2) was chosen as the best‐fitted model. For this fitted model, the activation energy was found to be 109.2 kJ/mol. Characterization of the catalyst was also performed using X‐ray diffraction (XRD), BET, scanning electron microscopy (SEM), and energy‐dispersive x‐ray spectrometer (EDS) techniques.

Selective hydrogenation of α‐pinene on a nickel supported aluminophosphate catalyst: Process optimization and reaction kinetics

“…Although linear equations are the common description forms for most of the reaction kinetics, researchers have found that in some cases linear forms could not describe the process well 43 . Non‐linear description has received growing attention in recent research and the method is indeed better for parameter calculations as the non‐linear form is consistent with the raw kinetic equations 44,45 . In the present study, the non‐linear method was utilized, and Origin version 9.4 was used to determine the kinetic parameters.…”

“…43 Non-linear description has received growing attention in recent research and the method is indeed better for parameter calculations as the non-linear form is consistent with the raw kinetic equations. 44,45 In the present study, the non-linear method was utilized, and Origin version 9.4 was used to determine the kinetic parameters. For the non-linear fitting, the rate equations with an indefinite integral form are listed in Table 7.…”

Fischer–Tropsch synthesis over the Co–Ni/Al2O3 nanocatalyst: influence of process variables, modeling and optimization using response surface methodology

“…Some investigators have reported the effect of operation parameters on the product distribution from cobalt-based catalysts [19][20][21][22][23] and showed that the olefin contents of the product spectrum decreased with increasing pressure, which was consistent with previous investigations. [24][25][26] In our previous works we used Co-Ni catalyst for production of lower olefins; 27,28 in these works, the preparation conditions of co-precipitated sample were optimized 27 and the kinetics and activity of impregnated sample were investigated. 28 In the current work we investigated the influences of process variables on the catalytic behavior of Co-Ni/Al 2 O 3 -impregnated nanocatalyst for lower olefin production.…”

“…[24][25][26] In our previous works we used Co-Ni catalyst for production of lower olefins; 27,28 in these works, the preparation conditions of co-precipitated sample were optimized 27 and the kinetics and activity of impregnated sample were investigated. 28 In the current work we investigated the influences of process variables on the catalytic behavior of Co-Ni/Al 2 O 3 -impregnated nanocatalyst for lower olefin production. In our previous works we investigated the impact of reaction conditions on the catalytic performance of different prepared catalytic systems.…”