Mechanism transformation of cyclohexene-thiophene competitive adsorption in FAU zeolite

doi:10.1016/j.cjche.2020.12.024

摘要/Abstract

摘要： Competition of hydrocarbon compounds with sulfides in gasoline has caused a not very high selectivity of sulfides in adsorption desulfurization so far, resulting in a reduction of catalyst lifetime as well as more sulfur oxide emissions. Tostudy the whole competitive process changing with the increase of the loading, the dynamic competition adsorption mechanism of cyclohexene and thiophene in siliceous faujasite (FAU) zeolite was analyzed by the Monte Carlo simulation. The results showed that with the increase of the loading, thiophene and cyclohexene had different performances before and after the inflection point of 40 molecule/UC. The adsorbates weredistributed ideally at optimal sites during the stage that occurredbefore the inflection point, which is called the "optimal-displacement adsorption" stage. When approachingthe inflection point, the competition became apparent and the displacement appeared accordingly, some thiophene molecules at S sites (refers to the sites inside the supercages) were displaced by cyclohexene. After the inflection point, the concentration of adsorbates at W sites (refers to the 12-membered ring connecting the supercages) was significantly reduced, whereas the adsorbates at S sites got more concentrated. The stage some cyclohexene molecules displaced by thiophene and inserted into the center of the supercage can be named as the "insertion-displacement adsorption" stage, and both the adsorption behavior and the competitive relationship became localized when the adsorption amount became saturated. This shift in the competitive adsorption mechanism was due to the sharp increase of interaction energy between the adsorbates. Besides, the increase in temperature and ratio of Si/Al will allow the adsorbates, especially thiophene molecules to occupy more adsorption sites, and it is beneficial to improve the desulfurization selectivity.

关键词: Competitive adsorption mechanism, Cyclohexene, Thiophene, FAU zeolite, Molecular simulation, Selectivity

Abstract: Competition of hydrocarbon compounds with sulfides in gasoline has caused a not very high selectivity of sulfides in adsorption desulfurization so far, resulting in a reduction of catalyst lifetime as well as more sulfur oxide emissions. Tostudy the whole competitive process changing with the increase of the loading, the dynamic competition adsorption mechanism of cyclohexene and thiophene in siliceous faujasite (FAU) zeolite was analyzed by the Monte Carlo simulation. The results showed that with the increase of the loading, thiophene and cyclohexene had different performances before and after the inflection point of 40 molecule/UC. The adsorbates weredistributed ideally at optimal sites during the stage that occurredbefore the inflection point, which is called the "optimal-displacement adsorption" stage. When approachingthe inflection point, the competition became apparent and the displacement appeared accordingly, some thiophene molecules at S sites (refers to the sites inside the supercages) were displaced by cyclohexene. After the inflection point, the concentration of adsorbates at W sites (refers to the 12-membered ring connecting the supercages) was significantly reduced, whereas the adsorbates at S sites got more concentrated. The stage some cyclohexene molecules displaced by thiophene and inserted into the center of the supercage can be named as the "insertion-displacement adsorption" stage, and both the adsorption behavior and the competitive relationship became localized when the adsorption amount became saturated. This shift in the competitive adsorption mechanism was due to the sharp increase of interaction energy between the adsorbates. Besides, the increase in temperature and ratio of Si/Al will allow the adsorbates, especially thiophene molecules to occupy more adsorption sites, and it is beneficial to improve the desulfurization selectivity.

Key words: Competitive adsorption mechanism, Cyclohexene, Thiophene, FAU zeolite, Molecular simulation, Selectivity

Pei Xue, Meng Zheng, Longwei Wang, Liyuan Cao, Liang Zhao, Jinsen Gao, Chunming Xu. Mechanism transformation of cyclohexene-thiophene competitive adsorption in FAU zeolite[J]. 中国化学工程学报, 2021, 39(11): 68-78.

参考文献

[1] V.M. Bhandari, C.H. Ko, J.G. Park, S. Han, S. Cho, J.J.C.E.S. Kim, Desulfurization of diesel using ion-exchanged zeolites, Chem. Eng. Sci. 61(2006) 2599-2608.
[2] R. Prins, V.H.J. De Beer, G.A. Somorjai, Structure and function of the catalyst and the promoter in Co-Mo hydrodesulfurization catalysts, Catal. Rev. 31(1989) 1-41.
[3] Q. Huo, T. Dou, Z. Zhao, H. Pan, Synthesis and application of a novel mesoporous zeolite L in the catalyst for the HDS of FCC gasoline, Appl. Catal. A 381(2010) 101-108.
[4] F.P. Tian, Q.C. Shen, Z.K. Fu, Y.H. Wu, C.Y. Jia, Enhanced adsorption desulfurization performance over hierarchically structured zeolite Y, Fuel Process. Technol. 128(2014) 176-182.
[5] H. Mei, B.W. Mei, T.F. Yen, A new method for obtaining ultra-low sulfur diesel fuel via ultrasound assisted oxidative desulfurization, Fuel 82(2003) 405-414.
[6] M. Almarri, X.L. Ma, C.S. Song, Role of surface oxygen-containing functional groups in liquid-phase adsorption of nitrogen compounds on carbon-based adsorbents, Energ Fuel 23(2009) 3940-3947.
[7] M.A. Betiha, A.M. Rabie, H.S. Ahmed, A.A. Abdelrahman, M.F. El-Shahat, Oxidative desulfurization using graphene and its composites for fuel containing thiophene and its derivatives:An update review, Egypt. J. Pet. 27(2018) 715-730.
[8] A.W. Bhutto, R. Abro, S.R. Gao, T. Abbas, X.C. Chen, G.R. Yu, Oxidative desulfurization of fuel oils using ionic liquids:A review, J. Taiwan Inst. Chem. E 62(2016) 84-97.
[9] S.G. Zhang, Q.L. Zhang, Z.C. Zhang, Extractive desulfurization and denitrogenation of fuels using ionic liquids, Ind. Eng. Chem. Res. 43(2004) 614-622.
[10] J. Eßer, P. Wasserscheid, A. Jess, Deep desulfurization of oil refinery streams by extraction with ionic liquids, Green Chem. 6(2004) 316-322.
[11] C.P. Huang, B.H. Chen, J. Zhang, Z.C. Liu, Y.X. Li, Desulfurization of gasoline by extraction with new ionic liquids, Energ Fuel 18(2004) 1862-1864.
[12] L.C. Huang, G.F. Wang, Z.F. Qin, M. Dong, M.X. Du, H. Ge, X.K. Li, Y.D. Zhao, J. Zhang, T.D. Hu, J.G. Wang, In situ XAS study on the mechanism of reactive adsorption desulfurization of oil product over Ni/ZnO, Appl. Catal. B-Environ. 106(2011) 26-38.
[13] L. Wu, F. Ye, D. Lei, G. Miao, B. Liu, Z. Li, J. Xiao, Regeneration of AgXO@SBA-15 for reactive adsorptive desulfurization of fuel, Pet. Sci. 15(2018) 857-869.
[14] X.L. Ma, S. Velu, J.H. Kim, C.S. Song, Deep desulfurization of gasoline by selective adsorption over solid adsorbents and impact of analytical methods on ppm-level sulfur quantification for fuel cell applications, Appl. Catal. BEnviron. 56(2005) 137-147.
[15] C. Song, An overview of new approaches to deep desulfurization for ultra-clean gasoline, diesel fuel and jet fuel, Catal. Today 86(2003) 211-263.
[16] J. García-Martínez, M. Johnson, J. Valla, K. Li, J.Y. Ying, Mesostructured zeolite Y-high hydrothermal stability and superior FCC catalytic performance, Catal. Sci. Technol. 2(2012) 987-994.
[17] S. Al-Khattaf, The influence of Y-zeolite unit cell size on the performance of FCC catalysts during gas oil catalytic cracking, Appl. Catal. A 231(2002) 293- 306.
[18] J. Scherzer, Designing FCC catalysts with high-silica Y zeolites, Appl. Catal. 75(1991) 1-32.
[19] Y.C. Qin, Z.S. Mo, W.G. Yu, S.W. Dong, L.H. Duan, X.H. Gao, L.J. Song, Adsorption behaviors of thiophene, benzene, and cyclohexene on FAU zeolites:Comparison of CeY obtained by liquid-, and solid-state ion exchange, Appl. Surf. Sci. 292(2014) 5-15.
[20] H. Li, X. Han, H.HuangY. Wang, L. Zhao, L. Cao, B. Shen, J. Gao, C.J.J.o.C. Xu, I. Science, Competitive adsorption desulfurization performance over K-Doped NiY zeolite, J. Colloid Interface Sci. 483(2016) 102-108.
[21] Y.C. Shi, X.J. Yang, F.P. Tian, C.Y. Jia, Y.Y. Chen, Effects of toluene on thiophene adsorption over NaY and Ce(IV)Y zeolites, J. Nat. Gas Chem. 21(2012) 421-425.
[22] H.G. Wang, L.J. Song, H. Jiang, J. Xu, L.L. Jin, X.T. Zhang, Z.L. Sun, Effects of olefin on adsorptive desulfurization of gasoline over Ce(IV)Y zeolites, Fuel Process. Technol. 90(2009) 835-838.
[23] X. Han, H. Li, H. Huang, L. Zhao, L. Cao, Y. Wang, J. Gao, C. Xu, Effect of olefin and aromatics on thiophene adsorption desulfurization over modified NiY zeolites by metal Pd, RSC Adv. 6(2016) 75006-75013.
[24] H.M. Zheng, L. Zhao, Q. Yang, S.Q. Dang, Y.X. Wang, J.S. Gao, C.M. Xu, Insight into the adsorption mechanism of benzene in HY zeolites:The effect of loading, RSC Adv. 6(2016) 34175-34187.
[25] S.Q. Dang, L. Zhao, J.S. Gao, C.M. Xu, Loading dependence of the adsorption mechanism of thiophene in FAU zeolite, Ind. Eng. Chem. Res. 55(2016) 11801- 11808.
[26] S.Q. Dang, L. Zhao, Q. Yang, M. Zheng, J.J. Zhang, J.S. Gao, C.M. Xu, Competitive adsorption mechanism of thiophene with benzene in FAU zeolite:The role of displacement, Chem. Eng. J. 328(2017) 172-185.
[27] L.H. Duan, Z.L. Sun, D.S. Liu, Z.H. Dai, X.Q. Li, L.J. Song, Adsorption and diffusion of thiophene, benzene, n-octane, and 1-octene on FAU zeolites, Stud. Surf. Sci. Catal. 170(2007) 910-917.
[28] C. Papaioannou, G. Petroutsos, W.J.S.S.I. Gunsser, Examination of the adsorption of hydrocarbons at low coverage on faujasite zeolites, Solid State Ionics (1997) 799-805.
[29] L. Si, D. Guo, G. Xie, J. Luo, Mechanical properties and interface characteristics of nanoporous low-k materials, ACS Appl. Mater. Interfaces 6(2014) 13850- 13858.
[30] Z. Zhang, H. Liu, J. Zhu, B. Chen, H. Tian, Z. He, Molecular simulations of adsorption and diffusion behaviors of benzene molecules in NaY zeolite, Chin. J. Chem. Eng. 17(2009) 618-624.
[31] H.M. Zheng, L. Zhao, J.J. Ji, J.S. Gao, C.M. Xu, F. Luck, Unraveling the adsorption mechanism of mono- and diaromatics in faujasite zeolite, ACS Appl Mater Interfaces 7(19) (2015) 10190-10200.
[32] A. Takahashi, F.H. Yang, R.T.J.I. Yang, E.C. Research, New sorbents for desulfurization by p-complexation:Thiophene/benzene adsorption, Ind. Eng. Chem. Res. 41(2002) 2487-2496.
[33] S.G. Ju, Y.P. Zeng, W.H. Xing, C.L. Chen, Computer simulation of the adsorption of thiophene in all-silica Y and Na-Y, Langmuir 22(2006) 8353-8358.
[34] Y. Shi, W. Zhang, H. Zhang, F. Tian, C. Jia, Y. Chen, Effect of cyclohexene on thiophene adsorption over NaY and LaNaY zeolites, Fuel Process. Technol. 110(2013) 24-32.
[35] J. Wang, P. Liu, M. Boronat, P. Ferri, Z. Xu, P. Liu, B. Shen, Z. Wang, J. Yu, Organic-free synthesis of zeolite Y with high Si/Al ratios:Combined strategy of in situ hydroxyl radical assistance and post-synthesis treatment, Angew. Chem. Int. Ed. 132(39) (2020) 17378-17381.
[36] A.N. Fitch, H. Jobic, A. Renouprez, Localization of benzene in sodium-Y-zeolite by powder neutron diffraction, J. Phys. Chem. 90(1986) 1311-1318.
[37] P. Santikary, S. Yashonath, G.J.T. Ananthakrishna, A molecular dynamics study of xenon sorbed in sodium Y zeolite. 1. Temperature and concentration dependence, J. Phys. Chem. 96(1992) 10469-10477.
[38] L.M. Bull, N.J. Henson, A.K. Cheetham, J.M. Newsam, S.J.J. Heyes, Behavior of benzene in siliceous faujasite:A comparative study of deuteron NMR and molecular dynamics, J. Phys. Chem. 97(1993) 11776-11780.
[39] C. Bremard, J. Laureyns, M. Lemaire, G.J. Ginestet, Monte Carlo simulations and spectroscopic studies of the sorption and cosorption of group vi metal hexacarbonyls in faujasitic zeolites, J. AM.Chem. Soc. 117(1995) 9274-9284.
[40] A.D. Mallmann, D.J. Barthomeuf, Site-specific isotherms for benzene adsorption in Na-Y zeolite, J. Phys. Chem. 93(1989) 5636-5637.
[41] H. Zheng, L. Zhao, Q. Yang, J. Gao, B. Shen, C.J.I. Xu, Influence of framework protons on the adsorption sites of the benzene/HY system, Reasearch E.C. 53(2014) 13610-13617.
[42] A.B. Ene, T. Archipov, E.J. Roduner, Competitive adsorption and interaction of benzene and oxygen on Cu/HZSM5 zeolites, J. Phys. Chem. C 115(2011) 3688- 3694.
[43] H. Sun, H. Zhao, N. Qi, X Qi., K. Zhang, W. Sun, Y.J.R.A. Li, Mechanistic insight into the displacement of CH₄ by CO₂ in calcite slit nanopores:The effect of competitive adsorption, RSC Adv. 6(2016) 104456-104462.
[44] C. Liu, R. Bai, Q.S. Ly, Selective removal of copper and lead ions by diethylenetriamine-functionalized adsorbent:Behaviors and mechanisms,, Water Res. 42(2008) 1511-1522.
[45] B.S. And, F.J.L Docquir, Competitive adsorption of benzene and ammonia on NaEMT Zeolite:A quantitative infrared study, Langmuir 17(2001) 3341-3347.
[46] Z. Yan, S. Tang, X. Zhou, L. Yang, X. Xiao, H. Chen, Y. Qin, W. Sun, All-silica zeolites screening for capture of toxic gases from molecular simulation, Chin. J. Chen. Eng. 27(2019) 174-181.
[47] G. Bakhtiari, H. Ghassabzadeh, S.J. Royaee, M. Abdouss, M. Bazmi, Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent:Equilibrium and dynamic studies, Pet. Sci. 16(2018) 417-427.
[48] M. Rahmati, H. Modarress, Grand canonical Monte Carlo simulation of isotherm for hydrogen adsorption on nanoporous siliceous zeolites at room temperature, Appl. Surf. Sci. 255(2009) 4773-4778.