Overheat steam temperature multi-target control method of ultra-supercritical unit

Abstract

The invention relates to an overheat steam temperature multi-target control method of an ultra-supercritical unit, which is a multi-target control method consisting of an outlet temperature control method and a pipe wall metal temperature control method; by adopting a model forecasting control method, a steam temperature inert segment forecasting model and a wall temperature forecasting model areset up respectively; a bigger value of the bias values between two forecasting models and the actual measurement parameter is used as the one of feedback adjusting components; according to the feedback adjusting component in the model forecasting control method, two control targets of adjusting overheat steam temperature and finishing superheater metal wall temperature in the control feedback loopare reconciled to be the target of adjusting the post temperature of an object cooler of a front spraying guiding zone; the controller is designed specific to the object characteristics of the frontspraying guiding zone.

Description

technical field [0001] The invention belongs to the field of thermal power engineering control, in particular to a multi-objective control method for superheated steam temperature of an ultra-supercritical unit. Background technique [0002] Due to variable coal quality and complex boiler combustion conditions, domestic ultra-supercritical units often experience uneven local heat load distribution during operation. This phenomenon is particularly significant when the unit changes load at a relatively high rate. The consequence of uneven distribution of local heat load is that the metal temperature of some superheater tube walls is too high. When the outlet steam temperature of the superheater has not reached the rated temperature, the temperature of some metal tube walls will reach the alarm value. At this time, in order to ensure the safe operation of the boiler, the temperature of the metal tube wall of the superheater must be controlled. [0003] The superheated steam te...

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Problems solved by technology

[0004] 1) The operating intensity of the operators has increased significantly;

[0005] 2) The metal tube wall of the superheater is often overheated for a long time due to untimely manual operation, which affects the safety of the equipment;

[0006] 3) Due to the great difference between the wall temperature change characteristics and the steam temperature change characteristics, intervening the wall temperature by modifying the steam temperature setting value will often cause coupling oscillation, which will greatly reduce the overall superheated steam temperature control quality;

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