Reversible hydrogen sorption and kinetics of hydrogen storage tank based on MgH2 modified by TiF4 and activated carbon. (5th July 2018)

• Record Type: Journal Article
• Authors: Thongtan, Puttimate; Dansirima, Palmarin; Thiangviriya, Sophida; Thaweelap, Natthaporn; Suthummapiwat, Apirak; Plerdsranoy, Praphatsorn; Utke, Rapee
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 27(2018)
• Page Start: 12260
• Page End: 12270
• Publication Date: 2018-07-05
• Subjects: Reaction mechanisms -- Dehydrogenation -- Catalyst -- Additive -- Titration measurement; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.04.171
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: By doping with 5 wt % TiF4 and activated carbon (AC), onset and main dehydrogenation temperatures of MgH2 significantly reduce (Δ T = 138 and 109 °C, respectively) with hydrogen capacity of 4.4 wt % H2 . Up-scaling to storage tank begins with packing volume and sample weight of 28.8 mL and ∼14.5 g, respectively, and continues to 92.6 mL and ∼60.5–67 g, respectively. Detailed hydrogen sorption mechanisms and kinetics of the tank tightly packed with four beds of MgH2 TiF4 -AC (∼60.5 g) are investigated. De/rehydrogenation mechanisms are detected by three temperature sensors located at different positions along the tank radius, while hydrogen permeability is benefited by stainless steel mesh sheets and tube inserted in the hydride beds. Fast desorption kinetics of MgH2 TiF4 -AC tank at ∼275–283 °C, approaching to onset dehydrogenation temperature of the powder sample (272 °C) suggests comparable performances of laboratory and tank scales. Hydrogen desorption ( T = 300 °C and P (H2 ) = 1 bar) and absorption ( T = 250 °C and P (H2 ) = 10–15 bar) of MgH2 TiF4 -AC tank provide gravimetric and volumetric capacities during the 1 st -2nd cycles of 4.46 wt % H2 and 28 gH2 /L, respectively, while those during the 3 rd -15th cycles are up to 3.62 wt % H2 and 23 gH2 /L, respectively. Due to homogeneous heat transfer along the tank radius, de/rehydrogenation kinetics superior at the tank center and degrading forward the tank wall can be due to poor hydrogen permeability. Particle sintering and/or agglomeration upon cycling yield deficient hydrogen content reproduced. Highlights: Reduction of desorption temperature by 138 °C after doping TiF4 and AC into MgH2 . Mechanisms and kinetics of cylindrical tank (∼93 mL) filled with ∼60 g MgH2 –TiF4 –AC. Upon 15 cycles, 3.4–4.5 wt. % H2 and 22–28 gH2 /L obtained from MgH2 –TiF4 –AC tank. Homogeneous heat transfer along the tank radius (17.5 mm).