Online pipe anti-blocking method for utility boiler primary air pipe

Abstract

The invention discloses an online pipe anti-blocking method for a utility boiler primary air pipe. The method comprises the steps that firstly, leveling is carried out on the air speed of primary air and pulverized coal concentration of each coal mill; secondly, a coal pulverizing system test is carried out on the coal mill, and a pulverized coal grain size database is established; thirdly, a mathematic model is established, according to parameters in operation collected in real time and the pulverized coal grain size database, the minimum fluidizing velocity of pulverized coal conveying under the theory state is calculated, a theoretical value is corrected according to the actual operation condition, the corrected minimum fluidizing air velocity is compared with the primary air speed measured online, and guiding opinions of the primary air speed are given. The online pipe anti-blocking method for the utility boiler primary air pipe can avoid the defects brought by too high primary air speed that pulverized coal ignition is delayed, the electric current of a primary air fan is too large, and air leakage of an air preheater is increased, and achieve energy saving and consumption reducing under the condition that the primary air pipe is not blocked.

Description

technical field [0001] The invention relates to a method for online calculation of the minimum fluidization velocity of pulverized coal transported in real time to prevent blockage of primary air ducts of power plant boilers, and belongs to the technical field of pulverized coal pneumatic transport in thermal power plants. Background technique [0002] The current large-scale power plant boilers mostly use coal as fuel. After the coal enters the coal mill through the coal feeder, the coal powder is developed, and then transported to the boiler by high-temperature and high-pressure primary air for combustion. The main function of the primary air is to preheat the pulverized coal and evaporate part of the moisture in the pulverized coal by heating; the second is to transport the pulverized coal as a carrier of pneumatic conveying. However, due to various reasons, during the primary wind pneumatic conveying process, the phenomenon that the pulverized coal usually blocks the pri...

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Problems solved by technology

[0004] 1. If the primary wind pressure is too high, it will increase the outlet pressure of the primary fan, and for axial flow fans, it will reduce the safety margin of the fan;

[0005] 2. As the primary air pressure increases, the air leakage of the air preheater will increase, which will reduce the efficiency of the boiler on the one hand; on the other hand, it will increase the output pressure of the induced draft fan;

[0006] 3. An increase in primary wind speed will prolong the ignition distance of pulverized coal, increase the possibility of carbon content in fly ash, and reduce boiler efficiency;

[0007] 4. An increase in the primary wind pressure will increase the output of the primary fan and induced draft fan, increase the power consumption rate of the plant, and thus increase the coal consumption of power generation

[0008] Through the above analysis, it is not difficult to find that increasing the primary air pressure is a last resort under the condition of sacrificing the economical efficiency and safety margin of the unit

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