Fabrication of Silica and Titania Anti-coking Passivation Layers in High Aspect-ratio Tubular Reactors by Atomic Layer Deposition†

doi:10.7503/cjcu20180374

Abstract

Abstract:

Silica and titania thin films were deposited inside the micro channels of stainless steel tubular reactors by atomic layer deposition(ALD) to suppress the metal catalyzed coke formation during thermal cracking of hydrocarbon fuels. Quartz crystal microbalance measurements reveal that the average film growth rate is 0.15 nm/cycle for silica and 0.11 nm/cycle for titania. The thicknesses of the passivation layers can be precisely controlled by changing the number of ALD cycle. In coking experiments, very thin films of silica or titania only show modest anti-coking performances and thicker coatings can effectively enhance the run lengths of the micro channel reactors. Generally, ALD titainia coatings perform better than silica coatings. The best anti-coking performance is obtained with a 1000-cycles ALD titania passivation layer, which can extend the lifetime of the reaction system by a factor of 4 to 5.

Key words: Atomic layer deposition(ALD), Surface passivation, Coke suppression, Titania, Silica

CLC Number:

O611.6
TB79

TrendMD:

HUI Longfei,LI Jianguo,GONG Ting,SUN Daoan,LÜ Jian,HU Shenlin,FENG Hao. Fabrication of Silica and Titania Anti-coking Passivation Layers in High Aspect-ratio Tubular Reactors by Atomic Layer Deposition^†[J]. Chem. J. Chinese Universities, 2019, 40(2): 201.

Figures/Tables 10

Fig.1 Schematic of the ALD system customized for fabricating anti-coking passivation layers on the internal walls of high aspect-ratio tubular reactors

Fig.2 Schematic picture for SEM characterization(A) and SEM images of the internal tube wall(B)

Fig.3 SEM images of the internal tube surfaces passivated by 250 cycles(A), 500 cycles(B), 1000 cycles(C), and 1500 cycles(D) of ALD SiO2

Fig.4 SEM images of the internal tube surfaces passivated by 250 cycles(A), 500 cycles(B), 1000 cycles(C), and 1500 cycles(D) of ALD TiO2

Fig.5 XPS spectra of different sample surface

Table 1 Surface composition(molar fraction, %) measured at different position of the internal tube walls by EDS

Element	Surface coated with 1000 cycles ALD SiO₂			Surface coated with 1000 cycles ALD TiO₂
Element	Inlet	Middle	Outlet	Inlet	Middle	Outlet
O	52.1	49.4	46.8	48.0	43.1	45.5
Si	12.0	11.4	10.6	N.A.^*	N.A.^*	N.A.^*
Ti	N.A.^*	N.A.^*	N.A.^*	21.0	18.4	19.5
Cr	9.3	10.1	12.2	9.6	13.8	10.1
Fe	22.5	24.4	25.6	19.9	21.8	23.2
Ni	2.7	3.3	3.2	0.7	1.7	1.0
Mn	0.3	0.6	0.8	0.8	1.2	0.7
Cl	1.1	0.8	1.0	N.A.^*	N.A.^*	N.A.^*

Fig.6 Thickness-time plots of SiO2(A, C) and TiO2(B, D) during ALD of passivation layers (C), (D) are the enlargement of (A), (B).

Fig.7 SEM images of the cokes formed in the un-passivated metal reactor(A) and on the internal tube surface(B)

Fig.8 SEM images of ALD SiO2 passivated metal surface after the coking experiments(A) 500 cycles ALD SiO2(destroyed oxide film); (B) 1000 cycles ALD SiO2(partially-destroyed oxide film); (C) 1500 cycles ALD SiO2(partially-destroyed oxide film).

Fig.9 SEM images of ALD TiO2 passivated metal surface after the coking experiments(A) 500 cycles ALD TiO2(destroyed oxide film); (B) 1000 cycles ALD TiO2(intact oxide film); (C) 1500 cycles ALD TiO2(partially-cracked oxide film).

References 37

[1]	Albright L. F., Marek J. C., Ind. Eng. Chem. Res.,1988, 27, 755-759
[2]	Froment G. F., Chem. Eng. Sci., 1981, 36(8), 1271-1282
[3]	Shen L. M., Gong J. M., Liu H. S., Huang Y. X., J. Shanghai Jiaotong Univ.,2014, 48(8), 1159-1163
	(沈利民, 巩建鸣, 刘焕胜, 黄玉霞. 上海交通大学学报, 2014, 48(8), 1159-1163)
[4]	Kumar P., Kunzru D., Can. J. Chem. Eng.,1987, 65(2), 280-285
[5]	Huang Y. F., Zhu Y. L., Xiong C. J., Pan Y. J., J. Beijing Univ. Aeron. Astron.,2011, 37(6), 753-756
	(黄艳斐, 朱岳麟, 熊常健, 潘英杰. 北京航空航天大学学报, 2011, 37(6), 753-756)
[6]	Wauters S., Marin G. B., Ind. Eng. Chem. Res.,2002, 41(10), 2379-2391
[7]	Mohamadalizadeh A., Towfighi J., Karimzadeh R., J. Anal. Appl. Pyrol.,2008, 82(1), 134-139
[8]	Abghari S. Z., J. Petrol. Sci. Eng., 2013, 2(2), 82-91
[9]	Jiang R. P., Liu G. Z., He X. Y., Yang C. H., Wang L., Zhang X. W., Mi Z. T., J. Anal. Appl. Pyrol.,2011, 92(2), 292-306
[10]	Edwards T., Combust. Sci. Technol., 2006, 178(1-3), 307-334
[11]	Guo Y. S., Fang W. J., Lin R. S., J. Zhejiang Univ-Sci. A,2005, 39(4), 538-541
	(郭永胜, 方文军, 林瑞森. 浙江大学学报(工学版), 2005, 39(4), 538-541)
[12]	Liu G., Han Y., Wang L., Zhang X., Mi Z., Energ. Fuel,2009, 23(1), 356-365
[13]	Hu W. X., Shen J., Zhou R. J., Dang Y. X., J. Petrochemical Universities,2017, 30(1), 1-7
	(胡文学, 沈健, 周如金, 党迎喜. 石油化工高等学校学报, 2017, 30(1), 1-7)
[14]	Wickham D. T., Engel J. R., Karpuk M. R., Preprint Paper Am. Chem. Soc. Div. Petrol. Chem.,2000, 45(3), 459-464
[15]	Mohan A. R., Eser S., Ind. Eng. Chem. Res.,2011, 50(12), 7290-7304
[16]	Zhou J., Xu H., Liu J., Qi X., Zhang L., Jiang Z., Mater. Lett.,2007, 61(29), 5087-5090
[17]	Yang C., Liu G., Wang X., Jiang R., Wang L., Zhang X., Ind. Eng. Chem. Res.,2012, 51(3), 1256-1263
[18]	Tang S., Hu S., Zhang Y., Wang J., Zhu Q., Chen Y., Li X., J. Anal. Appl. Pyrol.,2014, 107(5), 197-203
[19]	Tang S., Gao S., Wang S., Wang J., Zhu Q., Surf. Coat. Tech.,2014, 258(7), 1060-1067
[20]	Chien Y. Y., Chien F. L., Exp. Therm. Fluid. Sci., 2013, 47, 40-47
[21]	Jia S. Y., Yang W. G., Zhang B., Modern Paint & Finishing,2011, 14(1), 25-27
	(贾思洋, 杨万国, 张波. 现代涂料与涂装, 2011, 14(1), 25-27)
[22]	George S. M., Chem. Rev., 2010, 110(1), 111-131
[23]	Clark M. D., Maschmann M. R., Patel R. J., Leever B. J., Sol. Energ. Mat. Sol. C,2014, 128(5), 178-183
[24]	Díaz B., Härkönen E., $\acute{S}$wiatowska J., Maurice V., Seyeux A., Marcus P., Ritala M., Corros. Sci.,2011, 53(6), 2168-2175
[25]	Han D. S., Choi D. K., Park J. W., Thin Solid Films,2014, 552, 155-158
[26]	Hirvikorpi T., Vähä-Nissi M., Mustonen T., Liskola E., Karppinen M., Thin Solid Films,2010, 518(10), 2654-2658
[27]	Marin E., Lanzutti A., Lekka M., Guzman L., Ensinger W., Fedrizzi L., Surf. Coat. Tech.,2014, 211(3), 84-88
[28]	Roy A. K., Schulze S., Hietschold M., Goedel W. A., Carbon,2012, 50(3), 761-770
[29]	Gong T., Hui L. F., Zhang J. W., Sun D. A., Qin L. J., Du Y. M., Li C. Y., Lu J., Hu S. L., Feng H., Ind. Eng. Chem. Res.,2015, 54(15), 3746-3753
[30]	Gao S., Hu S. W., Zhu Q., Zhang Q. Y., Wang J. L., Li X. Y., J. Fuel Chem. Techno.,2014, 42(8), 1010-1017
	(高爽, 胡生望, 朱权, 张其翼, 王健礼, 李象远. 燃料化学学报, 2014, 42(8), 1010-1017)
[31]	Luan X. J., Xu H., Wang Z. Y., Zhou J. X., Zhu W., Chinese Petrol. Processing Petrochem. Technol.,2011, 42(5), 75-80
	(栾小建, 徐宏, 王志远, 周建新, 朱巍. 石油炼制与化工, 2011, 42(5), 75-80)
[32]	Tang S., Wang J., Zhu Q., Chen Y., Li X., ACS Appl. Mater. Inter.,2014, 6(19), 17157-17165
[33]	Du Y., Du X., George S. M., J. Phys. Chem. C,2007, 111(1), 219-226
[34]	Thielsch R., Gatto A., Kaiser N., Appl. Optics,2002, 41(16), 3211-3217
[35]	Du Y., Du X., George S. M., Thin Solid Films,2005, 491(1), 43-53
[36]	Foong T. R. B., Shen Y., Hu X., Sellinger A., Adv. Funct. Mater.,2010, 20(9), 1390-1396
[37]	Sun D. A., Du Y. M., Zhang J. W., Jiao Y., Li Y., Wang Z. X., Li C. Y., Feng H., Lu J., Fuel,2017, 194, 266-273