Low-coke-ratio blast furnace ironmaking technique

Abstract

The invention relates to a low-coke-ratio blast furnace ironmaking technique. Dry coal powder is pressurized and gasified in a separate gasification furnace, the dry coal powder is injected into the gasification furnace to be sufficiently mixed with pure oxygen, burnt and gasified to produce high-temperature coal gas, the pressure in the gasification furnace is 0.3MPa to 0.6MPa, and the temperature of the coal gas at the outlet is 1300 DEG C to 1550 DEG C; the coal gas at the outlet of the gasification furnace is mixed with the purified cold coal gas at the blast furnace top, and the temperature is controlled at 900 DEG C to 1050 DEG C; the high-temperature high-reducibility hot coal gas is then injected into the lower part of the body of the blast furnace, that is, the area above the root of a cohesive zone, so that the metallization ratio of charging can reach 85 percent to 95 percent when reaching the cohesive zone; and part of the coal powder is injected from the tuyere of the blast furnace to be subjected to pure oxygen combustion. The invention, which is a novel blast furnace ironmaking technique taking dead coal and oxygen as main energy sources, can reduce the coke ratio of the blast furnace to be less than 200kg, greatly increase the productivity of the blast furnace and reduce the emission of coke-making pollutant, thus enhancing the competitiveness of the blast furnace ironmaking technique.

Description

technical field [0001] The invention relates to an ironmaking process, in particular to an energy-saving and environment-friendly low coke ratio blast furnace ironmaking process. Background technique [0002] In recent years, the world iron and steel industry has developed rapidly, and the process of metal extraction from ore to pig iron has also made great progress. However, as far as the ironmaking process for producing steelmaking raw materials is concerned, the blast furnace is still the main process with an absolute advantage. [0003] If counting from the use of coke, the modern ironmaking blast furnace has a history of more than 300 years. The blast furnace mainly uses coke and artificial lump iron ore as the main raw materials. It smelts molten iron through physical and chemical processes such as fuel combustion, gasification, heat transfer, reduction, melting, and separation. It is a very efficient high-temperature multi-phase reactor. Modern large-scale blast fur...

AI Technical Summary

Problems solved by technology

[0005] In terms of direct reduction, the gas-based shaft furnace method (Midrex, HYL) has an absolute advantage, but they all need to use reformed natural gas as the raw material for reducing gas, so Can only be developed in areas with rich and cheap natural gas resources

At present, the dominant coal-based direct reduction method in the world is the rotary kiln method. The main advantage of this method is that it can directly use coal as fuel and reducing agent. Its disadvantages are high unit investment and low productivity (volume utilization coefficient 0.42t / m 3 d) The output of a single furnace is low (maximum 150,000 t / a), and the production cost is high, so the development is slow. Up to now, the production capacity of coal-based rotary kilns in the world is only 3 million t / a. my country has started research and development since the 1970s. So far, only 4 sets have been built in my country, forming a production capacity of more than 400,000 t / a

Images