Hydrogen Production from Cyclic Chemical Looping Steam Methane Reforming over Yttrium Promoted Ni/SBA-16 Oxygen Carrier

Abstract

Abstract:In this work, the modification of Ni/SBA-16 oxygen carrier (OC) with yttrium promoter is investigated. The yttrium promoted Ni-based oxygen carrier was synthesized via co-impregnation method and applied in chemical looping steam methane reforming (CL-SMR) process, which is used for the production of clean energy carrier. The reaction temperature (500-750 • C), Y loading (2.5-7.4 wt. %), steam/carbon molar ratio (1-5), Ni loading (10-30 wt. %) and life time of OCs over 16 cycles at 650 • C were studied to investigate and optimize the structure of OC and process temperature with maximizing average methane conversion and hydrogen production yield. The synthesized OCs were characterized by multiples techniques. The results of X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) of reacted OCs showed that the presence of Y particles on the surface of OCs reduces the coke formation. The smaller NiO species were found for the yttrium promoted OC and therefore the distribution of Ni particles was improved. The reduction-oxidation (redox) results revealed that 25Ni-2.5Y/SBA-16 OC has the highest catalytic activity of about 99.83% average CH 4 conversion and 85.34% H 2 production yield at reduction temperature of 650 • C with the steam to carbon molar ratio of 2.

Yttrium promoted Ni-based double-layered hydroxides for dry methane reforming

“…It was reported that doping with Y 3+ improved the rate of carbon removal due to oxygen vacancies, which persuaded oxygen radicals from CO 2 to react with coke. [35,39,53,62,63] Thus, a possible removal of carbon could have taken place according to the reverse Boudouard reaction (CO 2 + C = 2CO). [53] The latter may be also linked with possible re-dispersion of the Ni particles (described further in the text).…”

Experimental and Numerical Study of Low Temperature Methane Steam Reforming for Hydrogen Production

“…It is applied widely on large-scale industrial processes due to the low cost, easy accessibility and environmental-friendly nature [15]. It is normally used to maximize the average methane conversion and hydrogen production yield by employing nickel based oxygen carrier catalysts [16]. The temperature range of such process is between 500 and 750 • C [16].…”

“…It is normally used to maximize the average methane conversion and hydrogen production yield by employing nickel based oxygen carrier catalysts [16]. The temperature range of such process is between 500 and 750 • C [16]. Sorption enhanced reduction of the nickel oxygen carrier catalyst is used in chemical looping, aiming to capture CO 2 during conventional steam reforming [17].…”

Nanomaterials for Environmental Purification and Energy Conversion

“…[18]), H 2 evolution [25], and CO 2 reduction [26,27]. Six other papers focus on conventional catalysis ("dark" reactions), reporting efficient H 2 production [28,29], synthesis of ethanol and butanol [30], direct conversion of CO 2 and methanol to dimethyl carbonate [31], water purification [32], and advanced characterization of catalysts by X-ray absorption fine structure (EXAFS) spectroscopy [33]. The majority of studies have been performed with particulate catalysts (nanoparticles (NPs)), but organized nanostructures, such as nanotubes (TiO 2 /Cu x O y [18], carbon nanotubes (CNTs) [30,32]) and nanowires (CeO 2 [31]) have also been used.…”

“…The Fe 2 O 3 -MgAl 2 O 4 with narrowed mesopore-sized (2.3 nm) was successfully synthesized as an ultra-pure lattice oxygen transport medium. Furthermore, Daneshmand-Jahromi et al analyzed the role of yttrium promoted Ni/SBA-16 as an oxygen carrier in steam methane reforming [29]. The reaction temperature, Y and Ni loading, steam/carbon molar ration, and lifetime of the oxygen carrier were investigated.…”