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Xueqiang S.,North China Electrical Power University | Yan B.,North China Electrical Power University | Yuqiang D.,North China Electrical Power University | Qing-Neng C.,West Pacific Petrochemical Co.
Advanced Science Letters | Year: 2012

In view of the disadvantage that enterprises often adopt the subjective judgment of the experts to choose the equipments maintenance strategy, which is due to the lack of maintenance decision data in applications, a method based on fuzzy classifier is proposed here, that is using reliability and maintenance data in common database to construct the fuzzy classifier model, then classifying the production equipments of enterprises and choosing the optimal maintenance strategy according to different sorts. This method eliminates the disturbance from the factitious factors, enhances the practicability and validity of the maintenance strategy and procures favorable effect in applications. © 2012 American Scientific Publishers. All Rights Reserved. Source


Wang F.,Dalian University of Technology | Sun J.,Dalian University of Technology | Yan D.,Dalian University of Technology | Zhang S.,Dalian University of Technology | And 2 more authors.
Journal of Physics: Conference Series | Year: 2015

This paper discusses the fault feature selection using principal component analysis (PCA) for bearing faults classification. Multiple features selected from the time-frequency domain parameters of vibration signals are analyzed. First, calculate the time domain statistical features, such as root mean square and kurtosis; meanwhile, by Fourier transformation and Hilbert transformation, the frequency statistical features are extracted from the frequency spectrum. Then the PCA is used to reduce the dimension of feature vectors drawn from raw vibration signals, which can improve real time performance and accuracy of the fault diagnosis. Finally, a fuzzy C-means (FCM) model is established to implement the diagnosis of rolling bearing faults. Practical rolling bearing experiment data is used to verify the effectiveness of the proposed method. Source


Zhao Y.,Dalian University of Technology | Ma H.,Dalian University of Technology | Wang L.,Dalian University of Technology | Sun C.,Dalian University of Technology | Guo C.,West Pacific Petrochemical Co.
Acta Metallurgica Sinica (English Letters) | Year: 2011

A detailed knowledge of changes in microstructures and mechanical properties that occur in AISI 321 stainless steels service before and after solution treatment is of great interest, since the ductility and toughness of AISI 321 stainless steels may change drastically after service for a long time. After solution treatment at 1050 °C, the microstructures of AISI 321 stainless steels service for 80 000 h at 700 °C indicate that the content of sigma phase significantly decreased, the grains of austenite grew and the amount of twins together with the size increased with solution treatment time. The results of mechanical properties tests show that the impact toughness at room temperature was superior at solution treatment, and there was no obvious change in the impact toughness between different times of solution treatment at room temperature. Source


Liu C.,West Pacific Petrochemical Co. | Zhang F.,West Pacific Petrochemical Co.
Petroleum Processing and Petrochemicals | Year: 2013

The scale formation mechanism in slurry system of RFCC unit was introduced and analyzed. It is found the slurry scale is composed of catalyst, coke and metal compound and originates from deposition of catalyst, coking in transfer line, coking at the bottom of fractionator and slurry cycling with the coking in transfer line as the main reason. Stabilizing the operation conditions of RFCC unit will inhibit scale in transfer line from entering slurry system. Adding anti-scale agent in slurry is also an effective way to slow down scale formation. Source


Zhu W.,West Pacific Petrochemical Co. | Dong K.,West Pacific Petrochemical Co.
Petroleum Processing and Petrochemicals | Year: 2016

The problems of high H2S content in lean amine and in desulfurized gas in sulfur recovery plant of Dalian West Pacific Petrochemical Co. Ltd. were analyzed. It is found that the high amount of sodium ion (up to 7 800 μg/g) in amine solution is the key factor. The effective method to reduce Na+ from the amine solution, based on the lab experiment, is the on exchange technology. The hydrogen sulfide content in the lean amine solution of the industrial unit, after the on exchange treatment, is reduced from 4 g/L to 1. 5 g/L, and the desulphurization rate of the gases is improved significantly. The steam usage of the desufurization system decreases by 8 t/h. Source

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