Kinetics of adsorption of aromatic hydrocarbons and organic sulfur compounds by zeolite. [Alpha-decylthiophene, alkylbenzene, benzothiophene, phenanthiene, fluorene]
The ability of synthetic type X zeolites to adsorb large amounts of a substance that are present at low concentrations makes it possible to use the zeolites, in particular, for the thorough removal of aromatic hydrocarbons and organic sulfur compounds from complex mixtures of hydrocarbons. The prospects for development and growth in the use of these processes have made it necessary to study the kinetics of adsorption, which determine the feasibility of using zeolite under dynamic conditions. This paper reports on a kinetic study of the adsorption of aromatic hydrocarbons and organic sulfur compounds (Table 1) by crystals of binder-free NaX zeolite from binary solutions of the test compound in isooctane at a concentration of approximately 0.01 mole fraction. The results are presented in the form of the initial sections of the kinetic curves. It is shown that the rate of adsorption of /alpha/-decylthiophene is lower than those of the alkylbenzene and benzothiophene; the phenanthrene and fluorene molecules are adsorbed at practically the same rate. When the temperature is increased to 70/degree/C, the penetration into the micropore volume is accelerated particularly in the case of the 1,3-di-p-xylyl-2-amylpropane, and activated adsorption is observed. The dependence of the adsorption rate d/alpha/sub d//tau/ on the degree of coverage of the zeolite void spaces is determined by the size of the molecules and the temperature of the process; the lower the temperature and the greater the sizes of the molecules, the flatter is the curve for this relationship. It is concluded that for the thorough treatment of a paraffinic feedstock to remove traces of aromatic hydrocarbons and organic sulfur compounds, there may be kinetic hindrance due to the low diffusion coefficients of the molecules of these compounds at low degrees of coverage of the zeolite void space. 7 refs.
- OSTI ID:
- 6750332
- Journal Information:
- Chem. Technol. Fuels Oils (Engl. Transl.); (United States), Vol. 17:7-8
- Country of Publication:
- United States
- Language:
- English
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