Method and system for controlling outlet temperature of coal mill of direct-fired pulverizing system

Abstract

The invention provides a method and a system for controlling an outlet temperature of a coal mill of a direct-fired pulverizing system. The method comprises the steps that a content of nitric oxide at an inlet of an SCR denitration system is acquired; an estimation model is established according to a relation between a dry-ash-free volatile component of furnace coal and the content of the nitric oxide of the inlet of the SCR denitration system, and the content of the nitric oxide is input into the estimation model to determine an estimated value of the dry-ash-free volatile component; and a coal mill outlet temperature control strategy is generated according to the estimated value of the dry-ash-free volatile component, and the outlet temperature of the coal mill is adjusted according to the control strategy. According to the method, the volatile component of coal entering a furnace can be judged in real time, the temperature of the outlet of the coal mill can be adjusted to an optimal value for operation on line according to a level of the volatile component of coal quality during operation, and it is guaranteed that boiler economical efficiency is optimal.

Description

Technical field [0001] The present disclosure relates to a control method and system for controlling the outlet temperature of the coal - blower system. Background technique [0002] The statement of this section is merely the background technology information related to the present disclosure, which is not necessarily constituting the prior art. [0003] The outlet temperature of the coal mill is closely related to the safety of the powder system and the economics of the boiler. Improve the exit temperature of the coal mills to improve the efficiency of boiler, reduce the coal consumption of coal-fired fire generator sets, economic benefits are considerable. However, the upper limit of the outlet temperature of the coal mill is protected from the powder, the risk of pulverization, the risk of knocking, the higher the coal-fired volatile points, the higher the ratio of self-combustion, the more detonating, the lower the coal outlet temperature required to control. Improve the exi...

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Problems solved by technology

[0004] Usually, the volatile content of coal into the furnace is obtained through industrial analysis methods, which need to go through the steps of coal sampling, sample preparation, chemical analysis, etc., which takes several hours, and cannot be used as a timely judgment of coal quality changes during the operation of the coal mill. based on

Therefore, during the actual operation of the thermal power plant, the operator cannot know the volatile content of the coal being burned into the furnace, so they have to tend to operate conservatively, control the outlet temperature of the coal mill at a low level, and avoid spontaneous combustion of the pulverizing system , deflagration accidents; and the outlet temperature of the coal mill is kept at a fixed value, which cannot be adjusted online in real time according to the change of coal quality, thus affecting the economy of the unit operation

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