Primary air control system and method for reducing hot air throttling loss of coal mill

Abstract

The invention discloses a primary air control system and method for reducing hot air throttling loss of a coal mill. The primary air control system comprises a target coal mill judgment module, a coal mill hot air adjusting baffle automatic control module and a primary air fan automatic control module. The method comprises the following steps: whether each coal mill belongs to a target coal mill or a non-target coal mill is determined through the target coal mill judgment module according to the obtained opening degree of a hot air baffle of the coal mill; the opening degree of the hot air baffle of a target coal mill is adjusted to 100% through the coal mill hot air adjusting baffle automatic control module, and other non-target coal mills adjust the opening degree of the hot air adjusting baffle according to the air volume of an inlet of the coal mill; and meanwhile, the output of the primary air fan is controlled and adjusted through the primary air fan automatic control module. The output of the primary fan is adjusted by utilizing the air volume of the coal mill with the maximum opening degree of the hot air baffle, so that the hot air baffle of the coal mill of the coal-fired unit can keep a large opening degree, throttling loss is reduced, and coal blockage of the coal mill caused by too low primary air pressure is effectively prevented.

Description

technical field [0001] The invention relates to the technical field of coal-fired power generation, in particular to a primary air control system and a control method for reducing hot air throttling loss of a coal mill. Background technique [0002] Coal-fired generator sets are generally equipped with a corresponding primary fan for drying the pulverized coal and transporting the pulverized coal to the furnace for combustion. In order to prevent the occurrence of coal blockage in the coal mill, the outlet temperature is too high or too low, etc., the ventilation volume of each coal mill needs to be adjusted at any time according to the coal supply, coal quality and raw coal moisture content. The ventilation volume of the coal mill is adjusted by the opening of the air door baffle at the entrance of each coal mill. In the current application technology, a fixed primary air pressure is determined according to the number of coal mills in operation and the maximum coal supply,...

AI Technical Summary

Problems solved by technology

[0003] However, during the actual operation of the unit, since the coal type, coal feed rate and raw coal moisture content of each coal mill change irregularly and quantitatively, the primary wind pressure cannot be adjusted accordingly according to these changes, resulting in: The primary air pressure is too low, even if the coal mill hot air baffles are fully opened, it cannot meet the ventilation volume requirements of all coal mills, causing the coal mills to block the grinding; or the primary air pressure is too high to cause the air door baffle opening of each coal mill If it is too small, it will cause a large throttling loss, and the current of the primary fan will increase. At the same time, the primary air pressure will also increase the leakage rate of the primary air side of the air preheater.

Images