Mercaptan adsorption for desulfurization using a batch microprocess
Aliasghar Mohammadi, Ali Azizzadeh, Farshad Raji
Abstract
In this study, a batch microprocess was developed for the adsorption of ethanethiol from petroleum gas (LPG), liquefied at −45 °C. This process involved microdevices with ZSM-5 zeolite covalently immobilized on the walls of the microchannels. The results indicated the effective removal of the thiol from the liquefied synthetic feed using the microprocess at short contact times. For instance, the thiol concentration of less than 0.005 mg EtSH/g feed was achieved at a contact time of 3 min for the initial thiol concentration of 0.5 mg EtSH/g feed. The ability of the microprocess to remove the thiol from LPG was investigated at different contact times, surface-to-volume ratios of microchannels, and initial thiol concentrations. The thiol removal significantly increased with prolonging the contact time. The effect of time, however, disappeared at long contact times. The thiol removal also showed an ascending trend by increasing the ratio. Furthermore, a phenomenological model was proposed to address the dynamics of the thiol removal. Accordingly, the dynamics was governed by the thiol diffusion toward the immobilized zeolites. In addition, the Freundlich adsorption equation was found to model well the experimental data under equilibrium conditions. Finally, a model was proposed for the operation of the microprocess.