Ni‐Al₂O₃/Ni‐foam catalyst with enhanced heat transfer for hydrogenation of CO₂ to methane

Abstract

Monolithic Ni‐Al2O3/Ni‐foam catalyst is developed by modified wet chemical etching of Ni‐foam, being highly active/selective and stable in strongly exothermic CO2 methanation process. The as‐prepared catalysts are characterized by x‐ray diffraction scanning electron microscopy, inductively coupled plasma atomic emission spectrometry, and H2‐temperature programmed reduction‐mass spectrometry. The results indicate that modified wet chemical etching method is working efficiently for one‐step creating and firmly embedding NiO‐Al2O3 composite catalyst layer (∼2 μm) into the Ni‐foam struts. High CO2 conversion of 90% and high CH4 selectivity of >99.9% can be obtained and maintained for a feed of H2/CO2 (molar ratio of 4/1) at 320°C and 0.1 MPa with a gas hourly space velocity of 5000 h−1, throughout entire 1200 h test over 10.2 mL such monolithic catalysts. Computational fluid dynamics calculation and experimental measurement consistently confirm a dramatic reduction of “hotspot” temperature due to enhanced heat transfer. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4323–4331, 2015

Dynamic Methanation of CO2 – Effect of Concentration Forcing

“…The steady‐state rate has the highest value for a stoichiometric mixture with 38.42 µmol g −1 s −1 . The TOF for the temperature of 300 °C and the pressure of 2 bar has a value of 0.143 s −1 , which is in good agreement with the value reported by Li et al with 0.1 s −1 .…”

Surface Oxidation of Supported Ni Particles and Its Impact on the Catalytic Performance during Dynamically Operated Methanation of CO2

“…The turnover frequency (TOF) at 250 °C was calculated as 0.02 s -1 or as 0.08 s −1 at 300 °C. The TOFs for Ni/Al2O3 methanation catalysts reported in the literature cover a broad range between 0.69 s −1 [11], 0.10 s -1 [18], 0.041-0.097 s −1 [12] and 0.5 × 10 −3 -2.4 × 10 −3 s −1 [17]. The achieved TOFs correspond to typical dimensions; however, it is difficult to compare the results due to the diverse reaction conditions applied in these studies.…”

“…Ni-based catalysts generally achieve good activity. In addition, due to the low cost and high activity, Ni catalysts have emerged as the most commonly-used methanation catalysts [11][12][13][14][15][16][17][18], since more active Ru catalysts [19,20] suffer from the high price of the noble metal. The most relevant catalyst support material in industrial methanation reactions is reported to be γ-Al 2 O 3 with a high surface area [19,21,22].…”

Molybdenum Disulfide–Alumina/Nickel‐Foam Catalyst with Enhanced Heat Transfer for Syngas Sulfur‐Resistant Methanation

“…The three strong peaks at 2 θ =44.5, 51.8, and 76.3° were assigned to the Ni (1 1 1), (2 0 0), and (2 2 0) planes of the Ni‐foam (JCPDS No. 04‐0850) only in the MoS 2 ‐Al 2 O 3 /Ni‐foam catalyst. In addition, peaks for the Ni 3 S 2 phase observed in the MoS 2 ‐Al 2 O 3 /Ni‐foam catalyst at 2 θ =31.1, 37.9, 49.7, 50.1, and 55.2° correspond to Ni 3 S 2 (1 1 0), (0 0 3), (1 1 3), (2 1 1), and (1 2 2) (JCPDS No.…”