350MW supercritical variable pressure operation coal burning boiler

Abstract

The invention provides a 350MW supercritical variable pressure operation coal burning boiler. The boil is a direct-current boiler with single medium reheat and supercritical variable pressure operation and comprises a single hearth and a chimney flue; the lower part of the hearth is a spiral tube coil water wall structure of a rifled pipe; the water walls at the middle part and the lower part of the hearth adopt a spiral tube coil; the water wall at the upper part of the heart adopts an ascending vertical pipe platen in sequence; the water walls at the middle part and the lower part of the hearth are connected with each other by a transitional header tank; a rotary air preheater is arranged at the lower part of the boiler; a flue gas temperature adjusting baffle is arranged in the chimneyflue above the air preheater; an economizer is arranged above the flue gas temperature adjusting baffle; a low temperature reheater and a low temperature superheater are respectively arranged above the economizer; a low NOX coal dust combustor is arranged at the lower part of the hearth; and burnaway air is arranged above the low NOX coal dust combustor. The invention provides a boiler which has single hearth, balances ventilation, discharges slag in solid state, has entire steel frame structure, and can solves the problem that the previous constant pressure operation type boiler is unmatchedwith parameters of a stream turbine.

Description

(1) Technical field [0001] The invention relates to the technical field of boilers, in particular to a supercritical coal-fired boiler. (2) Background technology [0002] In the supercritical parameter unit, for the boiler with variable pressure operation, its operation mode makes the working conditions more complicated, especially when the water wall of the boiler changes from rated load to partial load, its pressure changes in a large range, resulting in The phase change of the working medium in the water wall is particularly complicated, which makes the hydrodynamic characteristics and heat transfer characteristics of the water wall more complicated. During variable pressure operation, from the rated load to the minimum DC load, the operating pressure of the boiler will drop from supercritical pressure to subcritical, ultra-high pressure, and high pressure. The working fluid in the water wall changes from single-phase to two-phase fluid, and the temperature of the workin...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a single furnace, balanced ventilation, solid slag discharge, all-steel frame, reasonable structure, and a 350MW supercritical coal-fired boiler with variable pressure operation that can solve the problem of mismatching parameters between boilers and steam turbines in the previous constant pressure operation mode

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