| When the normal operation of the coal gasification equipment,often use electric heating and insulation layer wrapped insulation method to maintain the gas temperature in the synthesis gas pipeline at about 260 ℃,to prevent the synthesis temperature is too low and gas condensation,pitting and other phenomena.The current method of monitoring the temperature of the syngas pipeline is surface thermocouple temperature measurement method,because it can not be fully distributed monitoring,will affect the effect of monitoring the temperature of the syngas pipeline.In this paper,we propose a distributed fibre-optic temperature measurement method for wall temperature monitoring of syngas pipelines in coal gasification,and design a temperature measurement system that can monitor the wall temperature of syngas pipelines online in real time,combining the national key research and development programme with the field requirements of syngas pipelines.The main work of the thesis is as follows:(1)Analyzed the domestic and foreign research in the field of pipeline temperature condition monitoring and distributed fiber optic high temperature monitoring,and proposed a distributed fiber optic Raman temperature monitoring method for coal gasification syngas pipeline temperature monitoring based on distributed fiber optic Raman temperature measurement,which can achieve fully distributed online monitoring for syngas pipeline wall temperature of 240～270℃.(2)Combined with ANSYS software,finite element analysis of the temperature field around the syngas pipeline is carried out.Based on the simulation results,the temperature field distribution around the syngas pipeline was determined,the performance index design of the distributed sensing fiber was guided,and the optimization plan of the fiber layout at the experimental site was completed.(3)Developed a distributed fiber optic temperature measurement device for syngas pipeline field temperature monitoring,designed a single-core multimode polyimide coated high-temperature resistant fiber with stainless steel protection layer,developed a Visual Studio platform-based temperature measurement system for syngas pipeline of coal gasification on the host computer software,and used the developed system to conduct system performance verification experiments on a simulated pipeline heating experiment platform.The experimental results show that the developed fiber optic temperature measurement system can measure temperature in the range of 0～300℃and up to 350℃ in a short period of time,and the accuracy of temperature measurement is ±1℃,which can meet the demand for on-site temperature monitoring of syngas pipeline.(4)The 434.6m distributed high temperature resistant optical fiber was used for long time temperature monitoring experiments in a DN400 coal gasification synthesis gas pipeline site of a refining enterprise in East China.The distributed fiber optic temperature measurement equipment collected one data point every 0.2m,2173 temperature data were collected every minute,and the average temperature of the wall surface of the syngas pipeline was 246.5℃ during normal operation.Conclusion:The distributed fiber optic temperature measurement system based on Raman scattering can complete the real-time online temperature monitoring of the syngas pipeline in the field environment,and compared with the surface thermocouple temperature measurement method,the distributed fiber optic temperature measurement method can achieve full coverage measurement of the syngas pipeline wall. |
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