Research Of The Composite Air Leakage Prevention Technology For The Rotary Air Preheater

Rotary air preheater is boilers of thermal power generating units now commonly used a in the tail end of the flue gas heat exchange equipment. Rotary air preheater has small volume, compact structure, high thermal density, the weight of the complete machine, metal consumption and less dosage, easy to install and arrangement and low temperature corrosion features such as light. But at the same time the rotary air preheater air leakage from the disadvantage of large amount of. Main effects of Air Preheater Leakage: leakage of pipeline will be due in the flue gas moisture condensation precipitation caused by low temperature corrosion, part of the pipeline will be blocked by condensation; air leakage caused by induced fan load increased; caused a reduction in the thermal efficiency of the boiler, the coal loss increased. In short, the air leakage of air preheater will affect the unit’s efficient, stable and safe operation.The structure and working principle of the rotary air pre heater is introduced in this paper, the cause of air leakage of air preheater are analyzed, and found the main factors that affect the air leakage of air preheater, and sums up the calculation formula of the air preheater air leakage and air leakage rate. Air preheater hot to run in the rotor deformation caused by the air preheater rotor and the sector plate gap increases causing the leakage problem, summarizes the currently based on the advantages and disadvantages of common methods of air leakage control, this paper presents the flexible seal and adjustable sealing combined composite air leakage prevention scheme, and the design of composite type air preheater air leakage prevention device. The design process of the flexible sealing device, adjustable sealing device and automatic control system, the control flow(including two modes including the position control and temperature control) were expounded.Rotary air preheater is a complex equipment, in order to ensure the air pre heater operation, the safe, stable and reliable, in the rotary air preheater air leakage prevention scheme increased alarm protection and switching function, its main function is the alarm signal for emergency treatment, to ensure the safe and stable operation of the air pre heater. For traditional air preheater gap is measured by the use of eddy current sensor in the engineering actual problems existing in the process, the clearance measurement scheme based on laser displacement sensor is proposed, and the transmission circuit is designed.In this paper, the design of flexible sealing device test set, can be adjustable sealing device and automatic control system testing platform, the flexible sealing device, adjustable sealing device and automatic control system for the test, also through trial construction engineering verification of the composite air leakage prevention scheme. By comparing before and after the engineering trial, from theory and in fact prove the feasibility of this scheme, a solid foundation for the follow-up of the project promotion.