Talk about the furnace temperature
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Dear seniors who work in ammonia synthesis, could anyone explain the relationship between the temperature in the furnace combustion chamber, the temperature at the furnace outlet, and the negative pressure (the operating level of the exhaust fan)?
The level of negative pressure has a direct impact on the combustion performance of the first furnace section; as long as the combustion in this section is good, the temperature in its combustion chamber as well as the temperature at its outlet will naturally be high.
Show the relationship between the temperature in the first-stage furnace combustion chamber, the temperature at the outlet of the first-stage furnace, and the negative pressure (fan opening) In the case of Unit 1#’s edge-type furnace, there are many factors that influence the temperature in the first combustion chamber and the temperature at the outlet of this chamber. These factors include the volume of the radiation section, the surface area of the conversion tubes, the unevenness coefficient of those tubes, the magnitude of the process load, and the length of the flame. In other words, it comes down to the balance between the thermal loads in the radiation section and the convection section. A set of books titled “Chemical Industry Furnace Design Manual” compiled by the National Chemical Industry Furnace Design Center provides calculation methods and practical examples. Another book, “Tubular Heating Furnaces”, written by East China University of Chemical Technology, also offers calculation methods and examples, although it contains fewer examples. As for the relationship between furnace negative pressure and the opening degree of the exhaust fan, furnace negative pressure serves two purposes: one is to ensure stable combustion in the burners, and the other is to keep the furnace operating under negative pressure, thereby ensuring that it is only subjected to high pressure and not to negative pressure; if it were subjected to negative pressure, the furnace would bulge outward.
The temperature at the furnace outlet is generally maintained around 700–710 degrees. The negative pressure is determined based on the combustion conditions, as well as the temperatures after preheating by the workday process and after preheating the mixture.