Research Of The Thermal Power Station Radial Sealed-Control Technology On Hot End Of The Air-Preheater Of The Boilers

With boilers direction to the development of large-capacity in modern thermal power plant, the air pre-heater as a device of heat exchange is used widely in modern thermal power plant. It has a lot of advantage such as the structure of tight, outside dimension small, easy deployment, the temperature of the surface being heated higher, the corrosion of the dust gas is lighter and so on. But owing to the air pre-heater has intrinsic characteristic in structure and the high pressure in air side, there always some air leak into the smoke sides. Thus the thermal efficiency of the hearth and wind volume supply are affected seriously. When too much air leaking into smoke side, Not only makes the use of the electricity increased in the blower and the air-compressors, But also makes the fuel lack of the air. This makes the boiler run in low load, and has effect on running in safely, economic and steadily.The principle of the air pre-heater is introduced in this paper, the factor which affect the air leak of the air pre-heater also is analyzed. The fungus-shaped distortion of the rotor hot end makes the clearance of the radial airproof increased, so the leakage increase also. Aiming at that problem, the fuzzy control plan is proposed to achieve the air leakage control. At the same time, the corresponding protective measures of system is proposed to insure the system can running steadily and reliably.In order to achieve the air leak control effectively, the accurate measurement of the clearance caused by the rotor distortion in high temperature environment in need. But the conditional contact sensors have a high ratio of malfunction, so the air leakage control system is hard to apply steadily and reliably. A non-contact type eddy current displacement sensor has high reliability in high temperature used for the air leakage control system is introduced in this paper. The structure of the sensor and the circuit of the signal processing is dissertated in detail. It also obtain satisfied effect in the practical application. In the paper has carried on the simulation analysis to the control system using Matlab software. Finally, the project realization of the control system and some...