Analysis of mechanism of fouling increase on blades of FCCU power recovery expander

doi:10.11949/j.issn.0438-1157.20140994

Abstract

Abstract:

Addressing the problem of serious fouling on the blades of FCCU (fluid catalytic cracking unit) power recovery expanders in refinery, micro-morphologies of fouling and catalyst particle at inlet of power recovery expander were analyzed with scanning electron microscopy (SEM). The fouling on the blades consisted of catalyst particle with diameter mainly between 1 μm and 2 μm. Then the adhesion mechanism of the catalyst particle and the effect of various adhesive forces on the adhesion phenomenon were studied. The smaller the diameter of the particle, the easier the particle was adhered, which agreed with the result of SEM. The inner distribution of the velocity field simulated by CFD demonstrated the effect of adhesive force on the fouling.

Key words: FCCU, power recovery expander, adhesion, fouling, CFD

摘要：

针对近年来炼油厂中出现的催化裂化烟气轮机结垢严重问题, 采用SEM(扫描电子显微镜)对催化剂平衡剂、烟机入口催化剂颗粒和垢样进行了微观形貌的分析, 结果表明, 烟机叶片上的结垢主要是由1～2 μm的催化剂颗粒组成。对催化剂黏附在叶片表面的机理进行研究, 分析黏附力对黏附作用的影响, 结果表明, 催化剂颗粒粒径越小, 越容易被黏附, 与SEM的结果吻合。通过CFD模拟烟机流道内速度场的分布, 验证了黏附力对结垢的影响。

关键词: 催化裂化, 烟气轮机, 黏附, 结垢, CFD

CLC Number:

TK268.+2

FEI Da, HOU Feng, CHEN Hui, WU Xiaolei. Analysis of mechanism of fouling increase on blades of FCCU power recovery expander[J]. CIESC Journal, 2015, 66(1): 79-85.

费达, 侯峰, 陈辉, 吴晓磊. 催化裂化装置烟气轮机积垢及其增厚机理[J]. 化工学报, 2015, 66(1): 79-85.

References 20

[1]	Sadeghbeigi R. Fluid Catalytic Cracking Handbook: An Expert Guide to the Practical Operation, Design, and Optimization of FCC Units [M]. Amsterdam: Elsevier, 2012
[2]	Gladys N, Laura V. Analysis of rotor-blade failure due to high-temperature corrosion/erosion [J]. Surface and Coatings Technology, 1999, 120: 145-150
[3]	Cheng Guangxu (程光旭),Yang Yong (杨永), Zhi Hongli (支红利), Wang Baisen (王百森), Zhang Zhiqiang (张志强). Failure mode and criticality analysis of catalytic cracking flue gas energy recovery system [J].Chemical Engineering (China) (化学工程), 2005, 33 (1): 65-70
[4]	Yuan Fang (袁芳). Study and development of energy recovery system for catalytic cracking [D]. Xi'an: Xi'an Shiyou University, 2008
[5]	Gladys N, Laura V. Analysis of rotor-blade failure due to high-temperature corrosion/erosion [J]. Surface and Coatings Technology, 1999, 120: 145-150
[6]	Tabakoff W. Review—turbomachinery performance deterioration exposed to solid particulates environment [J]. Journal of Fluids Engineering, 1984, 106 (2): 125-134
[7]	Dowson P, Rishel D M, Bornstein N S. Factors and preventive measures relative to the high temperature corrosion of blade/disk components in FCC power recovery turbines//Proceedings of the Twenty-Fourth Turbomachinery Symposium [C]. 1995: 11-26
[8]	Dianguo H. Analysis on causes of scaling in flue gas turbine of FCCU and countermeasures [J]. China Petroleum Processing and Petrochemical Technology, 2011, 13 (1): 66-74
[9]	Xie Hongyong (谢洪勇), Liu Zhijun (刘志军). Powders Mechanics and Engineering (粉体力学与工程) [M]. Beijing: Chemical Industry Press, 2003
[10]	Tas N, Sonnenberg T, Jansen H, et al. Stiction in surface micromachining [J]. Journal of Micromechanics and Microengineering, 1996, 6 (4): 385
[11]	Hamaker H C. The London—van der Waals attraction between spherical particles [J]. Physica, 1937, 4 (10): 1058-1072
[12]	Israelachvili J N. Intermolecular and Surface Forces [M]. 3rd ed. New York:Academic Press, 2011
[13]	Butt H J. Electrostatic interaction in atomic force microscopy [J]. Biophysical Journal, 1991, 60 (4): 777-785
[14]	Hao H W, Baro A M, Saenz J J. Electrostatic and contact forces in force microscopy [J]. Journal of Vacuum Science & Technology B, 1991, 9 (2): 1323-1328
[15]	Butt H J. Measuring electrostatic, van der Waals, and hydration forces in electrolyte solutions with an atomic force microscope [J]. Biophysical Journal, 1991, 60 (6): 1438-1444
[16]	Parker G J, Lee P. Studies of the deposition of sub-micron particles on turbine blades [J]. Proceedings of the Institution of Mechanical Engineers, 1972, 186 (1): 519-526
[17]	Rouquerol J, Rouquerol F, Llewellyn P, et al. Adsorption by Powders and Porous Solids: Principles, Methodology and Applications [M]. New York:Academic press, 2013
[18]	Lidén E, Persson M, Carlström E, et al. Electrostatic adsorption of a colloidal sintering agent on silicon nitride particles [J]. Journal of the American Ceramic Society, 1991, 74 (6): 1335-1339
[19]	Seville J P K, Willett C D, Knight P C. Interparticle forces in fluidisation: a review [J]. Powder Technology, 2000, 113 (3): 261-268
[20]	Bayly C I, Cieplak P, Cornell W, et al. A well-behaved electrostatic potential based method using charge restraints for deriving atomic charges: the RESP model [J]. The Journal of Physical Chemistry, 1993, 97 (40): 10269-10280