Semi-tower three-flue double-damper added jet flow flue gas recirculation secondary reheating power station boiler

Abstract

The invention discloses a semi-tower three-flue double-damper added jet flow flue gas recirculation secondary reheating power station boiler, and relates to a bituminous coal, low-moisture brown coal or lean coal burning secondary reheating boiler for a thermal power station. All high-temperature heating surfaces are horizontally arranged. When the boiler is at medium and high loads, heat-absorption distribution between a primary low-temperature reheater and a secondary low-temperature reheater is controlled by adjusting a flue gas adjusting damper for a middle flue, primary and secondary reheating air temperature reaches rated values, an ejector hot primary air adjusting damper is opened when the boiler is at low and medium loads, flue gas is sucked from the back of a front flue economizer, flue gas and air mixture enters a hearth from the upper portion of a secondary air separation air box, the proportion of radiation heat transfer to convection heat transfer in the hearth is changed, flue gas volume flow is increased, and the opening of the ejector hot primary air adjusting damper is controlled, so that the secondary reheating air temperature can be maintained at the rated values in the section of 40% to 100% BMCR (boiler maximum continuous rating) without spraying water.

Description

(1) Technical field: [0001] The invention relates to a semi-tower type triple flue double baffle plus jet flue gas recirculation secondary reheating power station boiler relates to a secondary reheating power station boiler used in thermal power stations for burning bituminous coal, low moisture lignite or lean coal. (2) Background technology: [0002] The secondary reheating power station boiler used in the prior art thermal power station is used to supply steam to the secondary reheating turbo-generator set. Typical boiler side main steam temperature / primary reheating steam temperature / secondary reheating steam temperature design The value is 605°C / 623°C / 623°C. [0003] A typical secondary reheat turbo-generator set is equipped with a four-stage high pressure heater and a separate steam cooler with boiler feed water temperatures up to 330°C; the steam inlet temperature of the primary low temperature reheater and the steam of the secondary low temperature reheater The inle...

AI Technical Summary

Problems solved by technology

When the inlet of the furnace smoke recirculation fan is connected to the outlet of the economizer, high dust, high working temperature, low flue gas density, and high speed will reduce the reliability of the furnace smoke recirculation fan, MTBF (Mean Time Between Failures) decrease and power consumption increases; when the inlet of the furnace smoke recirculation fan is connected to the outlet of the dust collector, the flow rate on the smoke side of the air preheater increases by 10% to 20%, which will cause a significant increase in the exhaust gas temperature of the boiler and a decrease in boiler efficiency , the furnace smoke recirculation fan needs a higher pressure head, and the power consumption is huge; when the inlet of the furnace smoke recirculation fan is connected to the outlet of the induced draft fan, similarly, the flow rate on the smoke side of the air preheater will increase by 10% to 20%, causing boiler smoke exhaust The temperature increases significantly, the efficiency of the boiler decreases, and the power consumption of the induced draft fan increases by 10% to 20%

Images