Primary hot air bypass device of positive pressure direct blowing type coal mill and use method

Abstract

A primary hot air bypass device of a positive pressure direct blowing type coal mill comprises an upper bypass device, a connecting pipeline and a lower bypass device, the ends, away from a center coal falling pipe, of the upper bypass device and the lower bypass device are connected in parallel and connected with a primary hot air inlet pipe through the connecting pipeline, and hot air is blown into the connecting pipeline from the primary hot air inlet pipe and then blown into a secondary hot air outlet pipe through the connecting pipeline. Then blowing into an upper bypass device and a lower bypass device; the other ends of the upper bypass device and the lower bypass device are respectively connected to the upper end and the lower end of a central coal dropping pipe in the mill; and the upper bypass device can blow air downwards and obliquely downwards, and the lower bypass device can blow air downwards and obliquely upwards, so that hot air forms convection in the central coal dropping pipe in the mill. The primary hot air bypass device is simple in structure and low in implementation difficulty, the hot air flow of the primary air chamber of the coal mill is not increased, the flow speed at the nozzle ring is not increased, so that the abrasion of the coal mill is not increased, the flow field of an air powder mixture in the mill is not influenced, the pipe wall of the central coal drop pipe is protected, and the abrasion of the central coal drop pipe is reduced.

Description

technical field [0001] The invention belongs to the technical field of pulverizing systems, and in particular relates to a positive pressure direct blowing type medium-speed coal mill primary hot air bypass device and a use method. Background technique [0002] The coal mill output is divided into three types, grinding output, ventilation output, and drying output. In actual operation, the comprehensive output of the coal mill depends on the smallest of the three. [0003] In recent years, due to the tight supply of coal resources and rising carbon prices, in order to reduce the cost of power generation, coal-fired power plants in my country usually deviate from the designed coal types in the pulverization process, and generally use mixed coal as the fuel for coal-fired boilers. The mixed coal is often mixed with lignite, coal slime, sludge and biomass with high total water content, which affects the drying output of the coal mill. In order to increase the drying output, co...

AI Technical Summary

Problems solved by technology

The mixed coal is often mixed with lignite, coal slime, sludge and biomass with high total water content, which affects the drying output of the coal mill

In order to increase the drying output, coal-fired power plants often increase the primary hot air volume, which will increase the wind speed at the nozzle ring, resulting in an increase in the flow rate of the air-powder mixture and increased wear of the coal mill body

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