Environmental-friendly energy-saving blast-furnace oxygen ironmaking method

Abstract

The invention provides an environmental-friendly energy-saving blast-furnace oxygen ironmaking method which is as follows: oxygen is delivered to a blast furnace which is used for replacing an original blast-furnace hot blast stove system to finish blast-furnace ironmaking. In the blast furnace, the oxygen reacts with coals to generate a reducing agent which chemically reacts with iron ores, so that iron oxides in the iron ores are reduced to metal irons, simultaneously the released heat is used as main heat of the blast furnace, and a small amount of cokes is used for providing parts of heat for the blast furnace and playing a ventilation role in stock columns and a gasifying carburetion role in cast irons; and coal gas on the top of the blast furnace is led in the blast furnace for regulating the temperature of the blast furnace, and simultaneously CO2 and H2O in the coal gas are converted into CO and H2 reducing agents, thereby realizing recycle. By using the method, the equipment cost is saved, and the energy consumption and discharge of carbon dioxide are reduced, thus being environmental-friendly, effectively reducing the production cost, and improving the economic benefits.

Description

technical field [0001] The invention relates to an ironmaking method, in particular to an environment-friendly and energy-saving blast furnace oxygen ironmaking method. Background technique [0002] Generally, there are two methods commonly used in ironmaking. One is the blast furnace ironmaking method, which mainly uses the blast furnace and the feeding device connected to it and the blast furnace hot stove system. The top of the blast furnace is continuously loaded, and the hot air of about 1000-1400 ℃ preheated by the blast furnace hot blast stove is blown into the blast furnace from the tuyeres at the lower part of the blast furnace. and H 2 , the CO and H 2 As a reducing agent, it reacts chemically with iron ore at high temperature to convert iron oxides in iron ore such as Fe 3 o 4 , Fe 2 o 3 , Feo, etc. are reduced to metal molten iron, and discharged from the blast furnace taphole, and the gas is exported from the top of the blast furnace. After dust removal, a...

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Problems solved by technology

Although the technical and economic indicators of this ironmaking method are good, the process is simple, the production volume is large, and the efficiency is high, the hot blast provided to the blast furnace is pressurized and heated air, and the useful oxygen in the air accounts for less than 21%. When adding 3% oxygen to the oxygen-enriched coal injection, the sum of the two is only 24%, that is to say, in the process of pressurizing the air at about 0.45Mpa and heating at about 1000-1400°C, it accounts for about 76% of the energy of nitrogen. The energy consumption is unnecessary and wasted in vain, resulting in a waste of energy, and it will also increase the cost of auxiliary equipment and materials such as pipelines, valves, containers, and thermal insulation materials, resulting in more investment

Furthermore, since the hot air of the blast furnace hot blast stove is obtained by burning about 45% of the blast furnace gas, and each blast furnace needs to be equipped with several hot blast stoves, this will not only waste a lot of gas, but also cost a lot, and the maintenance cost is also high. Moreover, about 500Kg of coke is needed to smelt one ton of iron. Taking coke as the main heat source and reducing agent of the blast furnace not only makes the cost high but also causes great pollution to the environment.

The other is the non-blast furnace ironmaking method, which uses coal-based direct reduced iron technology and equipment. Compared with the blast furnace ironmaking method in terms of cost, energy consumption, quality and scale, it still has certain shortcomings. Different degrees of gap

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