Monte Carlo simulations of nitrogen and hydrogen physisorption at high pressures and room temperature. Comparison with experiments

Abstract

The excess surface adsorptions of nitrogen and hydrogen gases on graphite basal planes at a temperature of 293 K have been computed by numerical simulations. The results of the simulations are compared to experimental data on the adsorption of these two gases measured on activated carbons. The adsorption isotherms have been calculated up to 600 MPa, and the experimental isotherms have been measured in the pressure range from 0 to 500 MPa for nitrogen gas and up to 60 MPa for hydrogen gas. Both theoretical and experimental nitrogen adsorption isotherms have similar shapes. They present a maximum at moderate pressures, then decrease toward a constant value or a shallow minimum followed by a slight increase at very high pressures. In addition, we compare the values of the hydrogen adsorption computed by simulation at a temperature of 77 K and low pressures with those recently measured. The qualitative agreement between experimental and simulations results is rather good for both gases at the temperatures considered.

Hydrogen/hydrocarbon phase equilibrium modelling with a cubic equation of state and a Monte Carlo method

“…Also investigating hydrogen adsorption, Cracknell [28] proposed a representation in which the hydrogen molecule is modelled by two Lennard-Jones spheres, one centered on each hydrogen nucleus. Finally, Darkrim et al [29] proposed a model including a single Lennard-Jones sphere model with a quadrupole moment. In their investigation of this model, Lisal et al [30] describe the quadrupole moment with a discrete distribution of charges: two positive electrostatic charges on the hydrogen nuclei and a negative charge on the Lennard-Jones centre.…”

“…2. Comparison of the reference hydrogen compressibility factors from Younglove [32] and the calculated ones with the model of Hirschfelder et al [23], Darkrim et al [29], Craknell [28] and the corresponding state theory [27]. whatever the temperature (AAD about 8%).…”

“…• a unique Lennard-Jones sphere with parameters from Hirschfelder et al [23], • a unique Lennard-Jones sphere with parameters derived from the theory of corresponding states [27], • a Lennard-Jones sphere and a quadrupole moment described with three charges according to Darkrim et al [29] and Lisal et al [30], and • two Lennard-Jones spheres centred on the hydrogen nuclei, according to the parameterization of Craknell [28]. The parameters involved in these models are recalled in Table 2.…”

Graphene nanostructures as tunable storage media for molecular hydrogen

“…In the attempt to understand and improve the storage capacity of graphitic materials, calculations have been made on many models. Some of the calculations were based on empirical interaction potentials (5)(6)(7)(8)(9), and the others used potentials derived from quantum mechanical calculations (10)(11)(12)(13)(14)(15)(16). The role of quantum behavior of molecular hydrogen at low temperatures has also been investigated (6,8,(17)(18)(19).…”

Materials towards carbon-free, emission-free and oil-free mobility: hydrogen fuel-cell vehicles—now and in the future

“…A new approach is extending the temperature range above the liquid hydrogen temperature and the room temperature. Hydrogen absorbing alloy (metal hydride) and its improved hybrid tank system are also very attractive, but material cost and high-performance material development stall implementation (Darkrim et al 1999;Lamari et al 2000;Bénard & Chahine 2001;Gardiner et al 2004;Kojima et al 2005Kojima et al , 2006Mori et al 2005a,b,c;Bhatia & Myers 2006;Kabbour et al 2006;Poirier et al 2006;Furukawa et al 2007;Liu et al 2007;Vasiliev et al 2007;Richard et al 2009a,b).…”