Start-up method of dewatering capacity-enlarging start-up monotube boiler near steam heating boilers

Abstract

The invention discloses a method for starting a steam-heated boiler adjacent to a once-through boiler with drainage and capacity expansion. The high-pressure heater on the unit to be started is connected with a pipeline that can receive heating steam from other sources; Boiler feed water temperature rise; when starting in cold state or warm state or hot state, indirectly heat the heating surface of the boiler, increase the flow of feed water to above the minimum ignition flow after its temperature is close to the saturation temperature of steam heated by other sources, start the air and smoke system, and the boiler Ignition, use the bypass system to increase the thermal load as soon as possible after starting the pulverizing system, cut off the fuel and enter the normal starting mode after the thermal load of coal burning is higher than the minimum oil cut-off thermal load; When the temperature difference between the feed water and the boiler water wall is less than the specified value, increase the feed water flow rate to above the minimum ignition flow rate, and the boiler will be ignited. After the thermal load of coal combustion is higher than the minimum oil cut-off heat load, the fuel oil will be cut off and enter the normal start-up mode. The method of the invention has the effect of saving energy.

Description

technical field [0001] The invention relates to the field of thermal coal-fired generator sets, in particular to a method for heating and starting a DC furnace of a steam turbine generator set. technical background [0002] With the increasingly mature technology of coal-fired power plants and the continuous improvement of environmental protection requirements such as energy conservation and emission reduction, supercritical and ultra-supercritical parameters have been generally used for large thermal power units, so the once-through furnace has become the only choice. The start-up method of the DC furnace is different from that of the conventional drum furnace. As far as the world is concerned, at present, the drainage expansion start-up type and the boiler water circulation pump type are mostly used. These two start-up methods have their own advantages and disadvantages. Since the drain expansion start-up DC furnace has the advantages of simple and reliable system and low...

AI Technical Summary

Problems solved by technology

However, the start-up of hydrophobic capacity expansion has the following significant disadvantages: the start-up system has a large loss of soda water, and the characteristics of low-load and frequent start-stops are poor, especially when starting in an extremely hot state. There is a large temperature difference, it takes a long time to increase the feed water flow to the minimum ignition flow, which makes the extremely hot start-up time takes too long

However, this technology belongs to cold furnace cold air ignition, and about 50% to 65% of the coal in the ignition stage is wasted because it cannot be burned.

If a large amount of unburned pulverized coal remains inside or at the tail of the boiler, it will become a major hidden danger to the safety of the boiler

In addition, due to the low combustion rate of pulverized coal ignited by plasma under cold furnace conditions and the long combustion range of the flame, it is easy to cause permanent damage to the part of the convection heating surface when the evaporation is low.

In addition, existing plasma ignition technology requires that the burner angle cannot be oscillated, thereby limiting the method of adjusting the temperature of the reheat steam

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