Double reheat power station boiler with three rear flues and double rear baffles and capable of recycling jet flow flue gas

Abstract

The invention provides a double reheat power station boiler with three rear flues and double rear baffles and capable of recycling jet flow flue gas, and relates to a double reheat boiler which is used in a thermal power station and combusts bituminous coal, low moisture brown coal or lean coal. When the boiler bears a high load or a medium load, a worker adjusts a flue gas adjusting baffle on a rear flue so as to control heat absorption distribution between a low temperature super heater and a single low temperature reheater and between the low temperature super heater and a double low temperature reheater, and adjusts a flue gas adjusting baffle on a middle flue so as to control heat absorption distribution between the single low temperature reheater and the double low temperature reheater, and therefore enables single and double reheat air temperature to reach rated value. When the boiler bears the medium load or a low load, an ejector heat primary air adjusting baffle is opened, and sucks flue gas from the rear of the double low temperature reheater, a mixture of smoke and air enters a hearth from the lower portion of a smoke deflecting corner, a proportion of radiation heat exchange amount and convection heat exchange amount in the hearth is changed, flue gas volume flow is increased, the opening degree of the ejector heat primary air adjusting baffle is controlled so as to maintain the double reheat air temperature at the rating value in a range from 40% BMCR (boiler maximum continuous rating) to 100% BMCR, and no water needs to be sprayed.

Description

(1) Technical field: [0001] The invention relates to a secondary reheating power plant boiler with three flues and double baffles at the tail and jet flue gas recirculation, which relates to a secondary reheating boiler used in thermal power stations that burns bituminous coal, low-moisture lignite or lean coal. (two) background technology: [0002] The double-reheat power plant boiler used in the prior art thermal power plant is used to supply steam to the double-reheat turbo-generator set, and the design of the typical boiler-side main steam temperature / primary reheat steam temperature / secondary reheat steam temperature The value is 605°C / 623°C / 623°C. [0003] A typical double-reheat turbogenerator is equipped with a four-stage high-pressure heater and a separate steam cooler, and the boiler feed water temperature is as high as 330°C; the steam inlet temperature of the primary low-temperature reheater and the steam of the secondary low-temperature reheater The inlet tempe...

AI Technical Summary

Problems solved by technology

When the inlet of the furnace smoke recirculation fan is connected to the outlet of the economizer, the reliability of the furnace smoke recirculation fan will be reduced due to high dust, high working temperature, low flue gas density and high speed, and MTBF (Mean Time Bctween 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%

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