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

Abstract

The invention discloses a starting method for an adjacent steam heating boiler of a drainage expansion starting once-through boiler; wherein a high-pressure heater of a starting unit is communicated with a pipeline for receiving the heating steam; the steam makes a unit boiler increase the temperature for water through the high-pressure heater; when starting in the cold, warm or hot state, the boiler heating surface is indirectly heated; when the temperature of the boiler heating surface is close to the saturation temperature of the steam, the feedwater flow is added up to the lowest ignition flow or above; a wind and smoke system is started, and the boiler is ignited; after starting a powder making system, the heat load is increased as soon as possible through a bypass system; the oil burning is cut off after the coal burning heat load is higher the lowest oil cut-off heat load in order to enter the conventional starting mode; when starting in the hot state and after finishing blowing, the feedwater flow is added up to the lowest ignition flow or above when the temperature difference of the cold wall of the feedwater and the boiler water is smaller than the value set by regulations, and the boiler is ignited; the oil burning is cut off after the coal burning heat load is higher the lowest oil cut-off heat load in order to enter the conventional starting mode. The method provided in the invention has the energy saving effects.

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

Images