Control device of full-load supercritical water-cooled wall

Abstract

A direct-current unit is the main power of coal electricity, a power supply coal consumption index of the direct-current unit is worsened due to peak regulation operation, metal fatigue failure occursfrom time to time, a denitration device deviates from the optimal working condition and even exits, primary frequency modulation quality is lowered and is checked frequently, and even start-stop peakregulation is selected passively due to lowest load safety. The invention deeply analyzes the functional basis of a water-cooled wall, and determines that the problem root is the subcritical workingcondition of the once-through boiler water-cooled wall, which is not changed in the existing improvement measures, so that a full-load supercritical water-cooled wall control device model is provided,a special throttling assembly composition and secondary design boundary conditions are formulated, the water-cooled wall and a superheater can be reliably isolated, a steam-water phase change position can be fixed, the coal-water deep correlation can be decoupled, a set of novel control strategy is provided, and the creativity provides a root treating scheme for the problem so as to fully adapt to the low-coal-consumption deep peak regulation requirement. A control device is specially applied to flexibility transformation of a supercritical once-through boiler or newly-built coal-electricityengineering design, and breaks through the limit bottleneck for coal-electricity deep regenerative transformation.

Description

technical field [0001] The invention belongs to the field of thermal power generation, and in particular relates to a full-load supercritical water-cooled wall control device and its functional mechanism, which are mainly used in the transformation and new establishment of super (super) critical once-through boilers. Background technique [0002] The underlying logic of coal-fired power generation is the Carnot / Rankine cycle theory. In order to pursue higher thermal power conversion efficiency, the initial parameters of the steam entering the heat engine continue to increase. Drum boilers are no longer applicable, and once-through boilers are produced accordingly. The advantages of once-through boilers are less steel consumption, fast start-up speed, higher steam parameters, etc. With the use and promotion of super (super) critical once-through boilers, the power supply efficiency of units has generally improved, and the coal consumption of comprehensive power supply is basic...

AI Technical Summary

Problems solved by technology

Deep low-load and frequent load-changing operation modes seriously deteriorate the coal consumption index of comprehensive power supply, boiler water wall fatigue failure occurs from time to time, denitrification devices often deviate from the optimal working condition or even quit, and the quality of primary frequency regulation is often evaluated due to the decline, even due to the lowest load Safety and passive selection of start-stop peak shaving

In short, the current super (ultra)critical DC units cannot meet the needs of grid-connected low coal consumption and deep peak regulation

[0005] At present, the internal thread technology of the water wall, the orifice ring technology of the water wall, and the forced recirculation technology are adopted, so that the load adaptability has been lowered to a certain extent, and at the same time, the blockage of foreign matter in the orifice ring of the water wall and the fatigue of the internal thread pipe of the water wall are accompanied. failure, adding forced circulation pumps, etc., but they do not change the status quo of the subcritical operation of the lower-load water-cooled wall, which are essentially reformist methods

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