Study On Hydraulic Decoking On-line Monitoring Based On Optical Fiber F-P Sensing System

Delayed coking is very important in the modern oil refining production process,and hydraulic decoking as a decoking method which is widely used in delayed cokingprocess, it uses high pressure water which constantly impact on coke tower wall,making the coke loss, then the coke outflow from the chute of tower. At present, inthe process of production of petrochemical industry, mostly rely on the operators whodetermine whether coke water is clean and take appropriate measures by means oflistening the voice of the tower wall under the force of the water. Repeating cuttingcoke makes the high operating frequency and efficiency is relatively low.Aiming at the disadvantages of existing decoking operation, this paper studies akind of real-time monitoring systems based on hydraulic decoking process. Throughpicking up and analysis the audio signal of coke tower in the process of hydraulicdecoking, geting a technique method to monitor in the process of hydraulic decoking,analysising and of real-time display of the tower decoking position and the status ofthe decoking through the computer, which is used to guide the workers to operatedecoking under the tower or make the decoking process being fully automatedoperation. This paper made the following research：1. This paper analyzes the principles and the technology characteristics ofhydraulic decoking, combining with the characteristics of optical fiber sensing, it putforward a set of research method to monitor the process of hydraulic decoking basedon optical fiber Fabry-Perot (F-P) sensor.2. Based on the characteristics of hydraulic decoking the coke tower, this paperdesigned and prepared the fiber optic F-P acoustic emission sensor, at the same time,itset up a kind of demodulation system based on optical fiber F-P acoustic emissionsensor. Completed preliminary software programming to acquire data and analysispreliminary spectrum by LabVIEW.3. This paper did tests in the Lab and coke tower experimental, the monitoringresults show that: through the analysis of the audio signal picked up by the system,obtaining the clean degree of coke in hydraulic decoking. This paper is written about the design and manufacture of the optical fiber F-Psensor, the installation in the petrochemical coking tower, the completed dataacquisition based on LabVIEW and spectrum analysis of signal processing, comingup with the relationship and rules between the coke layer thickness and the audiosignal, which results in mointoring the working condition of hydraulic decoking, inorder to achieve the automation of hydraulic decoking provided the powerful basis.