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Studies of Adsorption Behavior of Sulfur Compounds in Selective Adsorption Desulfurization for Clean Fuel

Author: WangHongGuo
Tutor: SunZhaoLin
School: China University of Petroleum
Course: Chemical Engineering and Technology
Keywords: Selective adsorption Modified Zeolites FT-IR Acidity Desulfurization mechanism
CLC: O643.32
Type: PhD thesis
Year: 2010
Downloads: 345
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Abstract

Selective adsorption desulfurization is one of the hot topics of current research, however, since the selective adsorption desulfurization mechanism has not yet reached a consensus, especially in the presence of large amounts of aromatics and olefins, sulfide selective adsorption and competitive adsorption mechanism is unclear. Of sulfide adsorption behavior research to solve the key issues of the desulfurization technology has important guiding significance. Modified Y zeolite as adsorbent for selective adsorption desulfurization system of theoretical and experimental research on the basis of the review of previous work, made a number of valuable research. Using X-ray diffraction (XRD), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) and other methods to characterize the liquid phase ion exchange modified zeolite prepared, the preparation conditions and the desulfurization performance of the sorbent associate. Found that the adsorbent the desulfurization capacity with Y-type zeolite pore volume, specific surface area, such as physical properties of almost unrelated, closely related to the sodium ion exchange or metal cation load. With a cationic degree of exchange is the stronger the higher the desulfurization performance of the resulting adsorbent. In addition, the the cation valences on the adsorbent also affect the the sorbent desulfurization performance of important factors. The XPS showed CeY zeolite calcined prepared in an air atmosphere a metal cation Ce3. CE4 content increased, with increasing calcination temperature, by TEM observation to 800 ° C, part of the cerium ions is based on the state of aggregation exist. Determine the modified molecular sieve suitable desulfurization process conditions. The results show that when CeY, NiY and CuY oil ratios of 14: 1,20: 1 and 60: 1, desulfurization time of 4 hours, 5 hours and 6 hours, the adsorbent can simulate oil sulfides completely removed. The Ce desulfurization performance of Ni and Cu ion modified molecular sieve in order as follows: CeY lt; NiY lt; CuY. Modified molecular sieve desulfurization rate but its desulfurization effect in reverse order. Under a nitrogen atmosphere, the saturation adsorption of the molecular sieve after regeneration, regeneration performance is good. Fixed bed penetration the curve technology as well as SCD chromatography analysis and experimental techniques, combined with molecular simulation study to determine the mode of action between the adsorbate molecules and adsorbent adsorbent on the adsorption behavior of the fuel oil typical sulfide and adsorption configuration. The fuel oil sulfides main thiophenes sulfides main results show that the interaction between the sulfide and the adsorbent depends both on the nature of the cation modified, in turn depends on the structure of the sulfide itself. Different thiophenes organic sulfides and the mechanism of action of the same active component is different, there are also differences in different the cationic active component on the adsorption of the same kind of sulfides. Sulfide selective adsorption of olefins and aromatics. Found that there are significant differences in different cationic modified zeolite. The simulated oil content of olefins, aromatics, the greater, the greater the influence of the desulfurization performance of the modified molecular sieve. CeY zeolite olefin stronger than aromatics, impact sequence is benzene LT; the ortho xylene LT; 1 - octene ≈ 1 - hexene LT; cyclohexene LT; 1,5 - hexadiene. NiY and CuY, olefin and aromatics considerable influence order 1 - octene ≈ 1 - hexene ≈ 1,5 - hexadiene ≈ cyclohexene ≈ benzene lt; toluene lt; ortho-xylene. Olefin desulfurization performance of different adsorbents, its the influence order CeY gt; NiY gt; CuY aromatic hydrocarbon desulfurization performance of different adsorbents no significant difference. The results show that the surface acidity of the molecular sieve also plays a crucial role in the selective adsorption desulfurization process. Situ IR of pyridine adsorption measurement Modified Zeolites acidic results show that different cation exchange, the acid strength and acid modified molecular sieve distribution change, which CeY molecular sieve B acid value to 0.662 mmol / g, CuY molecular sieve B acid value of 0.306 mmol / g. The surface protonic acid caused by the presence of sulfides or sulfide with olefins catalyzed reaction, the formation of sulfide molecules or polymer is adsorbed on the adsorbent surface acidic hydroxyl groups, leading to the clogging of the zeolite channels, and seriously affect the adsorbent desulfurization capacity . Initially using different methods closely related to the modified molecular sieve passivation modulation Zeolite The amount of acid and acid distribution, and found that the desulfurization performance of the adsorbent and the adsorbent B / L values.

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