Study On On-line Monitoring Of Fiber Optic Sensing In Hydraulic Decoking

Delayed coking process is a very important production process in petrochemical enterprises,and hydraulic decoking is an important step in the process of delayed coking production.At present,it generally relies on the workers to listen to the sound of hydraulic decoking process to determine the status of the operation of decoking in the top of coke tower,which is about 50 meters high and filled with harmful gases.This leads to the workers can't accurately locate the position of decoking and determine the progress of decoking in the corresponding position.This kind of operation mode is not only low efficiency,but also causes huge energy consumption of water and electricity.What's worse,it will harm the health of workers.In order to save energy and enable the decoking workers conduct remote decoking operation in the ground operation room,a remote on-line monitoring of hydraulic decoking technology is needed to replace the current artificial experience of operation mode in the petrochemical industry.Therefore,a kind of on-line monitoring technology of fiber optic sensing in hydraulic decoking is studied in this paper.By processing the acoustic signal picked up by the fiber optic F-P(Fabry-Perot)acoustic sensor array which is uniformly distributed on the coke tower wall in the hydraulic decoking process based on DSP signal acquisition and processing unit,the progress of hydraulic decoking can be judged.The main contents of this paper are as follows:(1)According to the analysis of hydraulic decoking monitoring technology in petrochemical industry,it put forward using the fiber optic F-P acoustic sensors to monitor the progress of hydraulic decoking in petrochemical industry by combining with the advantages of fiber optic sensing technology.(2)A kind of on-line monitoring system scheme in hydraulic decoking based on fiber optic sensing was put forward by combining with the characteristics of DSP processor in signal processing,and the automatic Q-point maintaining light source based on SOA,photoelectric conversion circuit and signal acquisition and processing unit based on DSP in the system were designed.(3)The design and implementation of signal acquisition and processing software for on-line monitoring of fiber optic sensing were carried out.According to the requirements of fiber optic F-P acoustic sensing for signal processing and combine with the characteristics of DSP processor,the overall scheme of software design is determined.Finally,the design and implementation of the function modules of the software were carried out,including signal acquisition signal acquisition,digital filter algorithm,fast Fourier transform algorithm,pattern matching for thickness of coke layer and UART serial communication.(4)The test research of on-line monitoring in hydraulic decoking based on fiber optic sensing was done in the petrochemical field.The field test showed that the quantitative relationship between the change of the thickness of coke layer and the acoustic signal can be obtained by using this signal processing technology,and the progress of hydraulic decoking can be judged.