Methane Steam Reforming on the Pt/CeO₂ Catalyst: Effect of Daily Start-Up and Shut-Down on Long-Term Stability of the Catalyst

Abstract

An environmentally friendly auxiliary power unit requires catalysts operating in the cyclic mode, producing H2 at a steady rate with high CO2 selectivity and minimum CO clean-up. Here, 1% Pt/CeO2 catalyst was synthesized using the solution combustion synthesis method and investigated toward methane steam reforming reaction. Preliminary tests were performed by varying the steam-to-carbon ratio (S/C), gas hourly space velocity (GHSV), and time-on-stream (TOS). The catalyst showed near-equilibrium CH4 conversion and high H2 concentration (75% dry basis, N2-free) obtained at S/C = 2.8 and GHSV = 24 000 h–1. The catalytic activity was stable after 25 cycles of start-up and shut-down operations, equivalent to 150 h of TOS. X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques were used to characterize either the fresh and aged catalyst after 150 h of TOS.

Stability and Activity of Rhodium Promoted Nickel-Based Catalysts in Dry Reforming of Methane

“…To avoid homogeneous cracking and coking of hydrocarbons, highly active metals should be chosen [ 12 , 13 ]. Noble metals such as platinum (Pt), rhodium (Rh), and palladium (Pd) have been widely investigated due to their superior performance, but their high prices restrain their application [ 14 , 15 ]. Cheap transition metals are the potential switch.…”

Is There a Stable Deacon Catalyst? Computational Screening Approach for the Stability of Oxide Catalysts under Harsh Conditions

“…If a number of elements take part in a particular technical process, the number of possible reactions and reaction products quickly becomes intractable, especially if contaminants in the gas feed such as sulfur, water, halides, or traces of metals − contribute to the degradation. In addition to that, catalyst degradation happens on longer time scales than the main catalytic reaction(s), typically over the course of months or years, − and even start-up and shut-down protocols can have a significant impact on catalyst stability. , The long time scales, together with the complexity of multicomponent systems and reactor operation, make the study of catalyst degradation phenomena by computational methods highly challenging. The same is true for in situ or operando experimental methods that enable observation over only short time periods.…”

“…In addition to that, catalyst degradation happens on longer time scales than the main catalytic reaction(s), typically over the course of months or years, 17−20 and even start-up and shut-down protocols can have a significant impact on catalyst stability. 21,22 The long time scales, together with the complexity of multicomponent systems and reactor operation, make the study of catalyst degradation phenomena by computational methods highly challenging. The same is true for in situ or operando experimental methods that enable observation over only short time periods.…”

Material and Energy Balance Analysis for Urea Production from Biomass via Methane Steam Reforming

“…Three process steps are the main routes for urea synthesis. They are: (1) decomposition of methane gas (CH4), under high temperatures, into hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2); (2) reaction between hydrogen formed and nitrogen (N2) to synthesize ammonia (NH3) and finally (3) the reaction between ammonia and carbon dioxide (CO2) to form ammonium carbamate (NH2COONH4) and decomposed into urea ((NH2) 2CO) and water (H2O) (DAVEY et al, 2010).…”