Design Of Continuous Thermocouple Temperature Measuring System For High Temperature Fault Monitoring On Gasifier Wall

The gasifier is an important reaction equipment in the coal water slurry gasification unit.In order to ensure that the operation of the gasifier is normal,safe and effective,it is necessary to monitor the surface temperature of the furnace wall in real time to prevent the gap cracks caused by the temperature difference stress in the furnace,and then inducing serious accidents by the cross gas,such as the deformation of the furnace wall,the drum package and even the rupture.At present,the commonly used method of monitoring the temperature of the gasifier wall is limited to detect the highest temperature in one area of the furnace wall surface,and then a portable infrared thermal imager and other equipment are used to locate the site.In this thesis,it has been innovatively proposed that a grid distributed method of temperature measurement and location,by using the grid distribution of continuous thermocouples to detect the temperature of the furnace wall and achieving to locate the trouble-spots synchronously.The main work of the paper is as follows:1.On the basis of researching and analyzing the current status of temperature monitoring methods for gasifier wall at home and abroad,the thermoelectricity of continuous thermocouples and performance characteristics of multi-thermal source point are studied by practical measurements.Meanwhile,continuous thermocouples are used to install it on the gasifier wall with a grid distribution mode.Thus,the division of regionalization of the furnace wall surface has been realized.And then,the coordinate system is given to achieve the goal of monitoring and locating the high temperature fault points on the furnace wall.A kind of isothermal fixing device and temperature difference compensation method which does not destroy the strength of the existing furnace wall has been researched and developed,while it has solved the technical problem of the continuous thermocouple installation on the distributed surface of the gasifier wall.2.In view of requirements of inspection and synchronous positioning,a measurement and control unit of systems has been designed and developed.The main research work includes the design of the main control module,which can carry on acquisition and processing of datum and realize the location of a high-temperature point;the design of the array multi-channel temperature inspection module,which can switch the measurement channel through relays action,measure the temperature of the continuous thermocouple in turn,and accomplish temperature inspection;the design of the display module,which is designed to display the alarm location in real time.3.An experimental platform is built to test the accuracy of the temperature measurement and effectiveness of location about the system.It mainly includes heating device for simulating the wall temperature of gasifier,continuous thermocouple network,isothermal fixing device and measurement and control unit.And the software of operation measurement and control is written.Finally,the stability of thermometry and timeliness of the alarm location were tested and analyzed.When the alarm temperature was set at 210?,the system could alarm in real time,while the actual temperature range was 225.8~235.4?,which was slightly higher than the design temperature,and the possible reasons were analyzed.