Online diagnosis method for heat exchange performances of tri-sectional rotary type air preheater

Abstract

The invention discloses an online diagnosis method for heat exchange performances of a tri-sectional rotary type air preheater. The online diagnosis method is characterized by comprising the following steps: acquiring data, distributing an air leakage rate of the air preheater, correcting heat exchange efficiency with a smoke gas side according to the temperature of the smoke gas in inlet and outlet of the air preheater, calculating and correcting a ratio of air heat capacity to smoke gas heat capacity, calculating a target ratio of the heat exchange efficiency of the smoke gas side of the air preheater, the air heat capacity and the smoke gas heat capacity, diagnosing the heat exchange performances of the air preheated, and the like. According to the online diagnosis method disclosed by the invention, by comparing the ratio of the actually measured air heat capacity of the rotary type air preheater to the smoke gas heat capacity with the ratio of the smoke gas side heat exchange efficiency, the air inlet and outlet temperature difference and a target value, the performances are diagnosed to be reduced if the temperature difference and the heat exchange efficiency are lower than the target value and the heat capacity is larger than the target value, so that a purpose of precisely diagnosing the heat exchange performances of the tri-sectional rotary type air preheater on line is achieved, and the problems that a calculating method for the heat exchange performances of the tri-sectional rotary type air preheater is large in error and the heat exchange performances cannot be accurately diagnosed are solved.

Description

technical field [0001] The invention relates to the field of thermal equipment performance state monitoring and diagnosis, and relates to an online diagnosis method for the heat exchange performance of a three-chamber rotary air preheater. Background technique [0002] At present, the most important and direct index to measure and evaluate the heat transfer performance of rotary air preheaters is the ratio of air heat capacity to flue gas heat capacity proposed in the air preheater performance test standard ASME PTC4.3-1968 and flue gas side heat transfer efficiency. [0003] 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 air preheater's own gravity, mushroom-shaped deformation will occur, which will increase the radial clearance of the upper end...

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Problems solved by technology

[0005] 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 Real heat transfer performance of three-chamber rotary air preheater

However, the flue gas side heat transfer efficiency, air heat capacity and flue gas heat capacity ratio mentioned in the heat transfer performance diagnosis and calculation method of the three-chamber rotary air preheater introduced in the existing literature and patents are all based on ASME PTC4. 3-1968 standard, has not yet overcome and solved the above problems and defects

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

In addition, the distribution of the leakage rate of the primary air and secondary air in the three-division chamber is not considered, so that the accurate calculation and diagnosis of the heat transfer performance of the three-division chamber rotary air preheater cannot be realized

Therefore, it is not conducive to the early detection and timely treatment of the heat exchange performance changes of the three-chamber rotary air preheater

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