Optimization of process parameters of methane decomposition in a fluidized bed reactor using Ni-Cu/AI203catalyst

• Main Author: Palero, Marie Loren
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Methane; Hydrogen; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4085; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10923/viewcontent/CDTG005066_P.pdf
• Institution: De La Salle University

The Thermocatalytic Decomposition of Methane (TCD of Methane) is an alternative method to produce hydrogen. Hydrogen is emerging as a promising energy source as it is sustainable and environment-friendly. The use of fluidized bed reactors with this process avoids problems associated with packed bed reactors. Though TCD of methane has been extensively studied, less attention has been given to the optimization of the process. Thus, this study optimized the process parameters of methane decomposition using a fluidized bed reactor. These parameters were reaction temperature, space velocity and inlet methane concentration. The catalyst used was Ni-Cu/Al2O3. The loading was 14% nickel and 6% copper which was based from the maximum capacity of the alumina support. Optimization was performed using the Box-Behnken design of experiments. The use of design of experiments allows the study of both main and interaction effects. Knowledge of both effects result to a better understanding of the parameters on the process. High hydrogen yield of 2.26% was produced using a methane concentration of 10%, a temperature of 800oC and a space velocity of 20 l/gcat-hr. A small interaction effect between temperature and space velocity was observed. A quadratic model relating hydrogen yield with the parameters was developed with an R2 value of 0.99. The highest methane decomposition rate was obtained with 50% methane feed, 800oC and space velocity of 20 l/gcat-hr. A slight interaction is detected between methane concentration and temperature. A quadratic equation relating the rate of methane decomposition with the parameters methane concentration, temperature and space velocity was developed. The R2 value of the model is 0.95. For a high sustainability factor these parameters were 10% methane, 600oC and 60 l/gcat-hr. Temperature was the most significant factor affecting catalyst deactivation. A linear model relating sustainability factor with temperature was developed with a slightly lower R2 value of 0.71. -iv- De La Salle University For carbon yield, temperature was found to be the most significant parameter. A methane concentration of 26.76%, 800oC and space velocity 60 l/gcat-hr were the parameters that led to a high carbon yield. Characterization of the spent catalyst showed the formation of both nanofibrous carbon and carbon particles. The type of carbon produced was dependent on the reaction temperature employed.