Guide: In recent years, with the rapid development of industry, some factories and mines require higher and higher quality and temperature for the production of steam. Saturated steam boilers are no longer satisfied with the production needs, so how to obtain higher steam on a certain basis? First of all, we must choose superheated steam boiler as a new type of steam heating equipment.
In recent years, with the rapid development of industry, some factories and mines require higher and higher quality and temperature for the production of steam. Saturated steam boilers are no longer satisfied with the production needs, so how to obtain higher steam on a certain basis? First of all, we must choose a superheated steam boiler as a new type of steam heating equipment.
As we all know, when water is heated in a finitely sealed container, as the pressure rises, water molecules split into steam molecules. The steam we usually use are all saturated steam produced under a certain pressure. The temperature is proportional to the pressure. The density of vapor molecules in the space continues to increase, so the number of molecules returning to the liquid also increases. When the number of molecules entering the space per unit time is equal to the number of molecules in the returning liquid, the evaporation and condensation are in a dynamic equilibrium state. At this time, although evaporation and condensation are still going on, the density of vapor molecules in the space no longer increases. The state at this time is called the saturated state. The liquid in the saturated state is called saturated liquid, and its steam is called dry saturated steam (also called saturated steam). If the saturated steam continues to be heated, its temperature will rise and exceed the saturation temperature at that pressure. This kind of steam above the saturation temperature is called unsaturated steam (commonly known as superheated steam).
In the actual production and application fields, whether it is in papermaking, chemical, food, rubber, building materials, and textile industries, the temperature of about 200°-400° is used, and this temperature has exceeded the limit of the steam temperature in the saturated state. At this temperature, the boiler pressure must reach about 20-30 kg, so the cost of boilers and steam pipes will increase, which will bring certain pressure to the enterprise economy, and there are still uncertain high-pressure safety hazards.
The superheated steam boiler generally adopts the SZS type structure due to the superheater installed inside the boiler. The function is to heat the saturated steam from the drum into superheated steam with a certain temperature. After the flue gas passes through the superheater, the temperature is reduced to 400～500℃ , And then enter the tail flue. One of the heating surfaces in the tail flue is an economizer. It is composed of finned tubes with excellent heat dissipation effect, and its function is to preheat the feed water before entering the drum and reduce the exhaust gas temperature. The other rear heating surface is an air preheater. Its function is to heat the air to a certain temperature before entering the furnace, so as to improve the combustion and further reduce the exhaust gas temperature and improve the efficiency of the boiler.