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    Home > Active Ingredient News > Drugs Articles > Factors affecting the arrangement of heating surface of steam boiler

    Factors affecting the arrangement of heating surface of steam boiler

    • Last Update: 2014-08-12
    • Source: Internet
    • Author: User
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    The heating process of steam boiler working medium can be divided into three stages: water preheating, water evaporation and steam overheating The proportion of heat absorption in these three stages changes with the change of steam pressure The lower the steam pressure, the larger the proportion of evaporation heat, the higher the pressure, the smaller the proportion of evaporation heat, the larger the proportion of preheating heat and superheat heat For example, the proportion of low parameter boiler evaporation heat is 70% ~ 75%, and the heating surface is mainly evaporation heating surface The evaporation heat of medium pressure boiler accounts for about 66% and the superheat heat accounts for about 20% Generally, the convection superheater can be arranged The super high pressure and subcritical pressure boilers are generally reheat boilers, and the superheat and reheat heat account for more than 45%, so it is necessary to arrange wall type, platen type and convection type superheater combined systems Therefore, the boiler steam parameters have a great influence on the layout of the heating surface of the boiler The influence of the boiler capacity on the arrangement of the heating surface of the steam boiler the arrangement of the heating surface of the boiler is different with the different capacity of the steam boiler When the boiler capacity increases, the specific capacity increases slowly, so the area of large capacity boiler is smaller than that of small capacity boiler In small and medium-sized boilers, the area of furnace wall is relatively large, and the temperature of furnace outlet will not be too high after the arrangement of water cooling wall However, in large capacity boilers, the temperature of furnace outlet is still very high after the arrangement of water cooling wall Only when the radiant superheater and semi radiant superheater are arranged, the temperature of furnace outlet can be reduced to reach the allowable value Therefore, the boiler capacity is also a major factor affecting the layout of the heating surface of the boiler The influence of fuel properties on the layout of heating surface of steam boiler; the nature and type of fuel have a great influence on the layout of boiler Taking solid fuel as an example, volatile matter, moisture, ash and sulfur have a great influence on boiler layout Coal with low volatile content is generally not easy to ignite and burn out, which requires a larger furnace volume to ensure that the fuel has sufficient combustion time in the furnace In addition, a higher temperature of hot air is needed, that is, to increase the heating surface of air preheater When the moisture content of the fuel is large, it will cause the temperature of the furnace to decrease and the radiant heat absorption to decrease, so the air preheater should be arranged more When the ash content of the fuel is large, it will aggravate the abrasion of the convective heating surface In order to reduce the abrasion, the tower type arrangement can be adopted When the ash melting point is too low, the liquid slag discharge method can be adopted to ensure that there is no slagging at the furnace outlet and the rear heating surface When the sulfur content of fuel is large, various measures should be taken to prevent low temperature corrosion and ash plugging in the layout of boiler The rising speed of the water in the drum will increase, and there will be enough energy to bring out the highly dispersed small water droplets on the water surface, which will worsen the steam quality, especially when the load is fluctuating or overloaded, even if the salt concentration of the water is not large, there will be serious consequences of the co evaporation of soda water Steam boiler water level: if the water level of the steam boiler is too high, the steam space of the drum will be reduced, and the steam volume passing through the corresponding unit volume space will be increased, the steam flow rate will be increased, and the free separation space of the water drop will be reduced, which will bring out the water drop along with the steam, and also worsen the quality of the steam The fluctuation of the water level will also cause the steam to carry water instantaneously Pressure of steam boiler when the pressure of steam boiler drops suddenly, the volume of steam with the same mass will increase, and the volume of steam passing through the unit space volume will also increase In this way, small water droplets are easy to be taken out and affect the quality of steam.
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