On-line heat exchange performance diagnosis method for two-branch-bin rotary air preheater

Abstract

The invention discloses an on-line heat exchange performance diagnosis method for a two-branch-bin rotary air preheater. The on-line heat exchange performance diagnosis method is characterized by comprising the following steps of acquiring data; distributing the air leakage rate of an air preheater; correcting temperatures of flue gas at an inlet and an outlet of the air preheater; calculating and correcting the ratio of the flue gas side heat exchange efficiency to the air heat capacity to the flue gas heat capacity; calculating the target value of the ratio of the side heat exchange efficiency of the flue gas of the air preheater to the air heat capacity to the flue gas heat capacity; and diagnosing the heat exchange performance of the air preheater and the like. By comparing the ratio of the actually measured air heat capacity of the air preheater to the flue gas heat capacity, the flue gas side heat exchange efficiency and the air intake and exhaust temperature differences with the target values, if the temperature differences and the heat exchange efficiency are lower than the target values, and the heat capacity is greater than the target value, performances are diagnosed to be reduced, so that the aim of diagnosing the heat exchange performance of the two-branch-bin rotary air preheater accurately online is achieved; the problems that the calculating method of the heat exchange performance of the two-branch-bin rotary air preheater is high in error, and the heat exchange performance cannot be diagnosed accurately in the prior art are solved.

Description

technical field [0001] The invention relates to the field of thermal equipment performance state monitoring and diagnosis, in particular to an online diagnosis method for the heat exchange performance of a two-chamber rotary air preheater. Background technique [0002] At present, the most important and direct indicator for measuring and evaluating the heat transfer performance of rotary air preheaters is the ratio between air heat capacity and flue gas heat capacity proposed in the American Society of Mechanical Engineering ASME PTC4.3-1968. Ratio and flue gas side heat transfer efficiency. According to the ASME PTC4.3-1968 standard, the air leakage of the rotary air preheater is mainly concentrated in the radial clearance of the lower end surface, such as figure 1 shown. In fact, due to the uneven heating of the upper and lower end faces and the influence of the gravity of the air preheater, mushroom-shaped deformation will occur, which will increase the radial clearance...

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Problems solved by technology

[0003] Therefore, the ratio of flue gas heat transfer efficiency, air heat capacity and flue gas heat capacity of the rotary air preheater calculated according to my country's "Standard Method for Thermal Calculation of Boiler Units" and the American Society of Mechanical Engineering ASME PTC4.3-1968 standard cannot accurately reflect The real heat transfer performance of the rotary air preheater with two compartments

The flue gas side heat transfer efficiency, air heat capacity and flue gas heat capacity ratio mentioned in the rotary air preheater heat transfer performance diagnostic calculation method introduced in the existing literature and patents are all based on ASME PTC4.3-1968 standards, have not yet overcome and resolved the above shortcomings

The existing technology only considers the influence of air leakage from the radial gap of the lower end surface of the rotary air preheater on the heat transfer performance of the air preheater, and does not consider the air leakage from the radial gap of the upper end surface, so that it is impossible to realize the two-segment rotary type air preheater. Accurate Calculation and Diagnosis of Heat Exchange Performance of Air Preheater

Therefore, it is not conducive to early detection and timely treatment of changes in the heat transfer performance of the air preheater

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