Parallel operation axial flow primary fan automatic regulating method and device

Abstract

The invention discloses a parallel operation axial flow primary fan automatic regulating method and an automatic regulating device. According to the method, a fan current monitoring and comparison module is added on a fan pneumatic blade automatic control module, the current of more than two fans is firstly judged during fan air quantity regulation and control, and the air quantity regulation sequence of a fan is determined according to fan current quantity; the preferential increase of the movable blade opening degree of the fan with low current is used as an air quantity increase regulation condition; the preferential decrease of the movable blade opening degree of the fan with high current is used as an air quantity decrease regulation condition. The optimized control strategy is adopted, the headwind and stall problem of the primary fan is effectively avoided, and the automatic regulation quality of an axial flow primary fan is greatly improved, so guarantee is provided for boiler burning stability.

Description

technical field [0001] The invention relates to an automatic adjustment method and device for an axial-flow primary fan running in parallel, and belongs to the technical field of thermal power plant operation control. Background technique [0002] Coal-fired thermal power units equipped with a direct-blown pulverizing system rely on primary air to complete pulverized coal transportation, and the primary air is provided by a primary fan. Large-scale thermal power units are generally equipped with two high-lift axial-flow primary fans, which have an unstable working area. When two axial-flow primary fans are running side by side, if the adjustment is improper (it is very easy to occur when the coal mill is put into operation and the system resistance is large), once the working point of the fan enters the unstable working area, a stall phenomenon will occur, resulting in The output of the fan drops sharply and the pressure of the system fluctuates sharply, so that the transpo...

AI Technical Summary

Problems solved by technology

When two axial-flow primary fans are running side by side, if the adjustment is improper (it is very easy to occur when the coal mill is put into operation and the system resistance is large), once the working point of the fan enters the unstable working area, a stall phenomenon will occur, resulting in The output of the fan drops sharply and the pressure of the system fluctuates sharply, so that the transportation of pulverized coal is interrupted or the transportation volume fluctuates greatly, which seriously affects the combustion stability of the boiler, and even causes the boiler to stall

[0003] At present, the automatic adjustment strategy of the axial-flow primary fan of domestic large-scale thermal power units running in parallel is based on the performance and working conditions of the two fans are completely consistent, which deviates from the actual situation on site, and has the following problems: The amount of increase or decrease of the opening is automatically divided into two fans, and the operating status of the two fans is not distinguished.

In fact, due to the difference between the coal mill’s startup and shutdown status and operating conditions, the system resistance that the two primary fans need to overcome is very different, and the adjustment characteristics of the moving blades of the two primary fans are also different due to manufacturing and installation errors. They are not the same, so the rotor blades of the two primary fans adopt a synchronous and same-width adjustment mode, and it is very easy for the fan output deviation to increase, which will eventually cause the fan to grab the wind and stall

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