Air cooling temperature-controlled re-combustion chamber for direct reduction

Abstract

The invention discloses an air cooling temperature-controlled re-combustion chamber for direct reduction. The air cooling temperature-controlled re-combustion chamber comprises a re-combustion chamber body (1), and a smoke combustion system and a smoke cooling system which are arranged on the re-combustion chamber body, wherein the smoke combustion system and the smoke cooling system are same systems, and each system comprises a plurality of grades of air supplying systems (7) which are distributed at intervals from bottom to top along the height direction of the re-combustion chamber (1); each grade of air supplying system (7) comprises an air inlet pipe (8); each air inlet pipe (8) is provided with a plurality of air nozzles (9) for carrying out constant-temperature combustion in the re-combustion chamber body (1). The re-combustion chamber can be used for controlling that the temperature of each combustion region is not more than 1000 DEG C; various defects of a water cooling manner are effectively eliminated so that the requirements on various parameters including smoke temperatures, smoke oxygen-containing content, physical enthalpy, steam content and the like by adopting a follow-up process are met with high standards.

Description

technical field [0001] The invention relates to the technical field of smelting equipment, in particular to a recombustion chamber used for burning out combustible components in high-temperature flue gas discharged from the tail of a rotary kiln in a direct reduction process to generate high-temperature flue gas. Background technique [0002] The direct reduction method in non-blast furnace ironmaking refers to the ironmaking process in which iron ore is reduced to sponge iron below the melting temperature. The product is direct reduced iron (DRI), also known as sponge iron. [0003] Sponge iron has not been melted, and still maintains the shape of the ore. Due to the reduction and loss of oxygen, a large number of pores are formed. It is named after the shape of the sponge under the microscope. It is characterized by low carbon content (<1%) and preserves the gangue in the ore. . [0004] The direct reduction method is divided into two categories: gas-based method and c...

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Problems solved by technology

[0010] First of all, after cooling by spraying water, the liquid water turns into water vapor, and the flue gas rich in water vapor is used as the heat source of the grate machine, which is not good for the green pellet drying process, and it is easy to produce an over-humid layer, leading to catastrophic consequences

[0011] Secondly, after the high-temperature flue gas is cooled by water spraying, the oxygen content of the flue gas is low. As the heat source of the grate machine, it is not conducive to the oxidation and consolidation of the pellets, resulting in low strength of the pellets entering the kiln, which is easy to cause ring formation in the rotary kiln

[0012] Thirdly, the latent heat of liquid water turning into water vapor cannot be reused in the waste heat boiler, resulting in a great waste of energy. At 100°C, the heat of vaporization of 539Kcal per 1kg of water cannot be recovered in the waste heat boiler, because the waste heat boiler cannot convert water vapor turns back into water, releasing this heat

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