Square primary air duct flow equalizing device of coal mill inlet

Abstract

The invention provides a square primary air duct flow equalizing device of a coal mill inlet, which greatly reduces the difficulty of air volume measurement, realizes accurate measurement and controlof online primary air volume on the premise of not replacing an original air volume measurement system, and lays a good foundation for safe, environment-friendly and economic operation of a coal-firedboiler. The device comprises a square cold primary air duct and a square hot primary air duct, n sections of convex cold primary air duct transition sections are arranged at the output end of the square cold primary air duct; wherein N is a natural number greater than or equal to 2; the output tail end of each cold primary air duct transition section communicates with an inlet of a cold primary air bellow; all the cold primary air bellows are transversely arranged in the section width area of the square hot primary air duct at intervals, the cold primary air bellows are located in the area ofthe air inlet section of the square hot primary air duct, and the windward sides, facing the hot air, of the cold primary air bellows are air guide cambered surfaces which are necked down from bottomto top.

Description

technical field [0001] The invention relates to the technical field of multiphase flow numerical simulation calculation, in particular to a square primary air duct flow equalization device at the entrance of a coal mill. Background technique [0002] The primary air at the entrance of the coal mill of a large coal-fired boiler is a mixture of a hot air and a cold air. The cold and hot primary air pipes at the entrance of most boiler coal mills are square air ducts, and the hot primary air duct is relatively thick. It is used to control the air volume, and the primary cold air duct is thinner, mainly used to adjust the air temperature. [0003] Limited by site space and investment cost, generally the hot primary air and cold primary air are delivered to the area near the entrance of the coal mill in the form of the main pipe, and then lead out to the hot air and cold air branch pipes respectively, and then enter each unit through the mixing air duct after mixing. coal mill. ...

AI Technical Summary

Problems solved by technology

Therefore, the temperature at the initial mixing point of the hot and cold primary air is "clear and clear". The effect of field uniform distribution

[0005] Because the velocity field and temperature field in the mixing air duct at the entrance of the coal mill are seriously uneven, the measurement results of the primary air volume measurement system arranged in this area are distorted, resulting in improper control of the primary air-to-coal ratio, and the occurrence of grinding blockage, skipping, and flying A series of problems such as high content of ash combustibles, high concentration of nitrogen oxide emissions, and serious wear and tear of the pulverizing system have serious negative impacts on the safe, economical and environmentally friendly operation of coal-fired boilers

[0006] In engineering practice, many users continue to search for various new primary air volume measurement systems and replace measuring components from the perspective of air volume measurement systems, but practice has proved that they cannot fundamentally solve the problem

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