Hydrogen‐rich syngas production from chemical looping steam reforming of bio‐oil model compound: Effect of bimetal on LaNi _0.8 M _0.2 O ₃ (M = Fe, Co, Cu, and Mn)

Abstract

Summary Chemical looping steam reforming (CLSR) of acetic acid as bio‐oil model compound is a suitable way to produce hydrogen‐rich syngas. The LaNiO3 and LaNi0.8M0.2O3 (M = Fe, Co, Mn, and Cu) perovskites were prepared via the sol‐gel method. The perovskites were characterized by X‐ray diffraction (XRD), thermogravimetry (TG), and test activity of hydrogen‐rich syngas in a fixed bed. XRD and TG results showed that the coke generation on LaNi0.8Fe0.2O3 needs a lower decomposition temperature, and a stable structure was appeared after reaction. The activity order of hydrogen‐rich syngas on five types of perovskite is LaNi0.8Fe0.2O3 > LaNi0.8Co0.2O3 > LaNiO3 > LaNi0.8Mn0.2O3 > LaNi0.8Cu0.2O3 at 650°C, mole ratio of steam/carbon (2:1), and sample mixture flow (GHSV = 34 736 g of feed/(g catalyst h)). The CLSR of acetic acid with LaNi0.8Fe0.2O3 at GHSV = 43 992 g of feed/(g catalyst h) showed good stability. Correlated to experimental results, the adsorption energy of steam and acetic acid on five types of perovskite were calculated using density functional theory (DFT). The adsorption energy of steam (−0.61 eV) and acetic acid (−0.93 eV) of LaNi0.8Fe0.2O3 is maximum. This value of DFT calculation is well explained in the experimental results.

Developing Oxygen Carriers for Chemical Looping Biomass Processing: Challenges and Opportunities

“…[172] For LaNi x Fe 1-x O 3 perovskite oxygen carriers, tuning the Fe to Ni could result in optimal CLBP performance over repeated redox cycles. [177,178] When using perovskite OCs, special attentions must be paid to the reversibility of phase changes over long-term redox cycling. For example, deep reduction of CaMnO 3 could result in the irreversible accumulation of CaMn 2 O 4 , which is less reactive than CaMnO 3 .…”

Phase segregation mechanism of NiFe 2 O 4 oxygen carrier in chemical looping process

“…Density Functional Theory calculation showed that the existence of oxygen vacancies made the diffusion barrier of O ions in Fe 2 O 3 /Fe system smaller than that of Fe cations, 32 which provided a theoretical basis for suppressing the phase segregation of NiFe 2 O 4 -based oxygen carriers by controlling the concentration of oxygen vacancies via cation doping. Consequently, promoting the formation of oxygen vacancies in NiFe 2 O 4 -based oxygen carriers can effectively improve the diffusion rate of O ions, 33,34 and then inhibit the phase segregation of NiFe 2 O 4 -based oxygen carriers. In addition, the construction of appropriate pore structure is another important way to improve the diffusion rate of O ions for NiFe 2 O 4 -based oxygen carriers.…”

Development of activated biochar supported Ni catalyst for enhancing toluene steam reforming

“…Until now, many previous studies put forward that catalytic steam reforming of tar or tar model compounds is considered to be one of the acceptable development trends . A variety of catalysts have been studied to realize tar removal and H 2 production during the reaction of tar steam reforming, such as catalysts with active metals (Ni, Co, Fe) and supports (Al 2 O 3, SiO 2, olivine). Among these catalysts, nickel has been widely employed as active metal for tar removal due to its economic feasibility and high activity for aromatic hydrocarbons destruction .…”