Dry (CO2) reforming of propane over bimetallic Mo-Ni/Al2O3 catalyst: catalyst synthesis and reactor operation

Hydrocarbon reforming using CO2, a greenhouse gas, as a feedstock has attracted increasing attention due to the benefits of chemical valorisation of natural gas and CO2, which have an adverse impact on the environment. For hydrocarbon dry reforming, where the product stream H2: CO ratio is less than 3, synfuel production is more amenable for downstream methanol and other oxygenated synthesis. Dry reforming of propane has attracted much interest because of the associated lower reforming temperature and lower vapour pressure of propane compared with methane at ambient temperature, which makes it more favourable for fuel cell cars with internal reforming. However, the formation of carbon on Ni catalysts is well known, thus the addition of Mo to Ni would help in mitigating carbon deposition through possible conversion of the Mo oxide to a Mo carbide phase. Several authors reported high activity, stability and carbon resilience of the Mo-Ni catalyst during methane steam and dry reforming. Furthermore, it has been shown that potassium promotion also retards the nucleation of carbon. As a result, the present project investigates both reactor operation and the performance of Mo-Ni/Al2O3 catalyst as well as the effect of K-promotion on propane dry reforming at temperatures of 773 -973 K .The catalysts were prepared using wetness co-impregnation method. Alumina supported bimetallic 5(wt%)Mo-10(wt%)Ni was doped with 2.5 (wt%) K. Various characterization techniques were employed to measure the physicochemical properties of the catalysts. Specifically, N2-physisorption, H2-chemisorption, temperature-programmed calcination (TPC), temperature-programmed reduction (TPR), NH3 and CO2- temperature-programmed desorption (TPD), X-ray diffraction (XRD) and Total organic carbon (TOC) analyses were performed. K-promotion enhanced the BET surface area, pore volume, metal dispersion and metal surface area. XRD analysis of calcined catalysts confirmed the presence of metal oxides. TPD experiments revealed the acid : basic site ratio of 8.3 for Mo-Ni , while K-promotion decreased the value to 7.5 ,suggesting that basicity of the catalyst was improved by K addition.Catalytic reaction studies were carried out in a stainless-steel quartz fixed-bed reactor (ID = 15 mm ID) co-axially placed within a temperature-controlled tubular furnace and loaded with 0.5g of catalyst. Both Mo-Ni and K-containing catalysts were found to be promising for dry reforming of propane due to their high activity and stability under different operating conditions

Modelling of Liquid Hydrogen Boil-Off

A model has been developed and implemented in the software package BoilFAST that allows for reliable calculations of the self-pressurization and boil-off losses for liquid hydrogen in different tank geometries and thermal insulation systems. The model accounts for the heat transfer from the vapor to the liquid phase, incorporates realistic heat transfer mechanisms, and uses reference equations of state to calculate thermodynamic properties. The model is validated by testing against a variety of scenarios using multiple sets of industrially relevant data for liquid hydrogen (LH2), including self-pressurization and densification data obtained from an LH2 storage tank at NASA’s Kennedy Space Centre. The model exhibits excellent agreement with experimental and industrial data across a range of simulated conditions, including zero boil-off in microgravity environments, self-pressurization of a stored mass of LH2, and boil-off from a previously pressurized tank as it is being relieved of vapor