Kinetics of ethanol steam reforming over Ni/Olivine catalyst. (22nd August 2022)

• Record Type: Journal Article
• Authors: Bepari, Sujoy; Sarkar, Joy Jyoti; Pradhan, Narayan C.
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 72(2022)
• Page Start: 30843
• Page End: 30860
• Publication Date: 2022-08-22
• Subjects: Hydrogen -- Ethanol -- Steam reforming -- Olivine -- Nickel -- Kinetic study; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.02.032
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Olivine, a natural mineral consisting of different metal oxides (mainly Mg, Si and Fe oxides) was used as a support for nickel catalyst used in steam reforming of ethanol. Catalyst containing different wt% of Ni on olivine were prepared by conventional wet-impregnation method and characterized by BET, XRD, SEM (coupled with EDS) and H2 -TPR. The reaction was carried out in a tubular fixed bed reactor. Among all the catalysts, 5% Ni on olivine catalyst gave highest hydrogen yield as well as ethanol conversion through ethanol steam reforming reaction. The catalyst activity was analyzed by varying three important process parameters (temperature, ethanol to water molar ratio and space-time). The reaction was performed in the temperature range of 450 °C to 550 °C with 1:6 to 1:12 M feed ratio of ethanol to water at a space-time range 7.21–15.87 kg cat h/kmol ethanol. A maximum yield of 4.62 mol of hydrogen per mole of ethanol reacted was obtained at 550 °C with ethanol to steam molar ratio of 1:10 and space-time of 7.94 kg cat h/kmol ethanol with the ethanol conversion level of 97%. CHNS analysis of the spent catalyst was performed to find the coke deposited over the catalyst surface during the reaction. The power law and LHHW type kinetic models were developed. The power law model predicts the activation energy as 29.07 kJ/mol, whereas the LHHW type model gives the activation energy as 27.4 kJ/mol. Graphical abstract: Image 1 Highlights: Ni/Olivine catalysts of varying Ni content were synthesized for ethanol steam reforming. 5% Ni on Olivine catalyst exhibited best performance. The effects of different process parameters on catalyst performance were investigated. An optimum ethanol conversion of 97% and a hydrogen yield of 4.62 mol H2 /mol ethanol converted were obtained. Kinetic models were developed.