Abstract
Different metal ions were used to modify Hβ zeolite adsorbents by an impregnation method to remove organic chlorides from the model naphtha. The dechlorination performance of different ion-modified adsorbents was evaluated using a microcoulometer. The effects of calcination time and temperature, metal loading, adsorption time and temperature, and dosage of adsorbent were investigated by batch adsorption experiments. The modified adsorbents were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), NH3-temperature-programmed desorption (TPD), scanning electron microscopy (SEM), infrared spectroscopy of pyridine adsorption (Py-IR), and X-ray photoelectron spectroscopy (XPS). After modification, the modified Zn/Hβ zeolite exhibited the best dechlorination performance among the other metal-loaded zeolites. The removal percentage of organic chloride of the Zn/Hβ adsorbent prepared at optimum preparation and adsorption conditions can reach 72.54%, compared with 34.07% of Hβ zeolite. The Zn/Hβ adsorbent also maintained good dechlorination performance after regeneration by calcination for five times. The characterization results revealed that the concentration of the B acid sites in the zeolite decreased with the introduction of the metals, whereas that of the L acid sites increased. Zn/Hβ zeolite had the lowest B/L ratio but the best dechlorination performance, which meant that the type and amount of acidic sites present in zeolites played a significant role in dechlorination performance and L acid was beneficial for chloride compound removal.
Highlights
The organic chloride compounds in crude oil exhibit properties of polarity and electrophilicity, which would hydrolyze and convert into hydrogen chloride
The adsorbents were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), NH3 temperature-programmed desorption (NH3TPD), infrared spectroscopy of pyridine adsorption (Py-IR), Brunauer−Emmett−Teller (BET), and X-ray photoelectron spectroscopy (XPS)
Several metals were introduced to Hβ zeolites by impregnation to remove organic chlorides from the model naphtha, and Zn/ Hβ zeolite had the best dechlorination performance
Summary
The organic chloride compounds in crude oil exhibit properties of polarity and electrophilicity, which would hydrolyze and convert into hydrogen chloride. The methods for removing organic chloride in crude oil mainly include catalytic hydrodechlorination, dechlorination using a chlorine transfer agent, and dechlorination by adsorption methods. The aryl glycols produced in this process were immiscible with the nonpolar liquid, and the two-phase system ensured the efficient removal of the product This method consumes a large amount of the organochlorine transfer agent and has a long reaction time, which would limit its further application. Typical adsorbents are silica gel,[18] activated carbon,[19] activated alumina,[20] molecular sieves,[21] and some special adsorbents Among these adsorbents, zeolite adsorbents are widely used for adsorption desulfurization,[22−24] denitrification,[25] and the removal of volatile organic compounds[26−28] in the production of basic organic chemicals and exhibit excellent performance in the removal of organic chlorine. The adsorbents were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), NH3 temperature-programmed desorption (NH3TPD), infrared spectroscopy of pyridine adsorption (Py-IR), Brunauer−Emmett−Teller (BET), and X-ray photoelectron spectroscopy (XPS)
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