Gas adsorption and desorption

Rouquerol J. and Davy L. (1991) French Patent cm device for integral and continuous measurement of gas adsorption and desorption, filed 25/10/1991. 

During the last few years many studies of the behaviour of sulfur on and with metallic surfaces have been published and have provided a more complete understanding of the interaction processes. They have included gas adsorption and desorption kinetics, surface and grain boundary segregation, embrittlement, sulfidation, corrosion, passivation, catalyst poisoning, among others. 

Numerical modelling of outbursts requires the quantification of a number of processes and factors. These include gas adsorption and desorption, coal deformation and failure, coal fragmentation, gas dynamics and transport of outburst coal (particle flow). 

In the Langmuir treatment of the kinetics of gas adsorption and desorption, the rate of adsorption is equated to the rate of desorption as follows ... 

ABSTRACT In order to investigate the effect of coal particle size on gas desorption and diffusion law at constant temperature, the constant temperature dynamic coal particle gas adsorption and desorption experiment with different particle sizes was conducted in the coal gas adsorption and desorption experiment system. The results suggest that gas desorption laws of different particle size of coal samples show a good consistency at different pressures, and the cumulative desorption of gas coal particle is linear with time. For the same particle, the higher the initial pressure, the more the maximum gas desorption the smaller the coal particle is, the more quickly the gas desorption rate is at the same initial pressure. Then, the gas spherical flow mathematical model is built based on Darcy law and is analysed with finite difference method. At last, the gas spherical flow mathematical model is constructed with Visual Basic. The contrast between numerical simulation and experimental results shows that the gas flow in the coal particle internal micropore accords with Darcy s law. 

The coal gas isothermal adsorption and desorption experiment system mainly includes coal gas adsorption and desorption experiment system, data acquisition system, constant temperature system, weighing system and drying of degassing system. In order to investigate the effect of coal... 

Fig. 10.4 Reversible gas adsorption and desorption of PtII complexes 1 containing the pincer ligand via formation of a colored pentacoordinated adduct 2 (Reprinted with permission from Albrecht and van Koten 1999, Copyright 1999 WILEY-VCH Verlag)...

Figure 6.32. Experimental setup for measurements of gas adsorptions and desorption processes within a column [6.3, 6.10].

Kitamura S, Miyamoto K, Tsujino R (1994) The Evaluation of gas-liquid reaction rate at bath surface by the gas adsorption and desorption tests. Tetsu-to-Hagane 80 101-106... 

First, we investigate Ga adsorption and desorption kinetics in vacuum. The sample vras held at a constant temperature of 740 °C. Ga adsorption/desorption isotherms were recorded by monitoring the intensity of the specularly... 

Figure 6.11 The four stages of Ga adsorption and desorption for the example of

Next, Ga adsorption and desorption in the presence of an active N flux is investigated. The sample was held at a constant temperature of 740 °C and exposed to an active N flux of 0.275 MLs . Ga adsorption/desorption isotherms were recorded exactly as described above. Ga fluxes range from 0.19 to 1.66 MLs . The behavior observed is analogous to that shown in Figure 6.10, and we thus interpret it in the same way. Quantitatively, the adsorbed amount of Ga at the end of stage I was found to be 3 MLs, that is, higher than for adsorption in vacuum [61]. 

Thermogravimetry [HAI 02] involves measuring the uninterrapted solid-phase total mass on a thermobalance. This total mass is modified by each step that consumes and/or produces a gas. These steps are in general the gas adsorption and desorption steps. Steps occurring inside the solid phases do not modify the total mass of these solids. 

Fig. 6.27 Barrett-Joyner-Halenda (BJH) sorption curves for the fly ash, activated fly ash residues and reference zeolite 4A (RZP), where black arrows represent dominant pore diameters corresponding to N2 gas adsorption and desorption...

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