RU2377313C1 - Feeding method of natural gas into blast furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy field, particularly to blast manufacturing and can be used at melting of cast iron in blast furnaces with blowing-in of natural gas into blower nozzles. Method includes heating of natural gas by means of its feeding in the capacity of cooling medium for cooling of components of tuyere apparatus by means of bypass connecting branch, located between tuyere apparatus and collector for feeding of natural gas. In the capacity of cooling medium natural gas is fed at a pressure 3-12 kg/cm² with consumption 1000 m³/h, at a moment blowing and stop of blast furnace in the capacity of cooling medium it is fed nitrogen at a pressure 3-12 kg/cm² with consumption 50-800 m³/h.

EFFECT: productivity improvement of blast furnace, reduction of consumption of carbon-bearing materials.

1 dwg

Description

The invention relates to the field of ferrous metallurgy, namely to blast furnace production, and can be used in the smelting of pig iron in blast furnaces with the injection of natural gas into air lances.

A known method of supplying natural gas to a blast furnace [1] selected as a prototype is known, including preheating it before entering the air lance, introducing hot blast into the stream and feeding it into the furnace, in which heating is carried out by using natural gas as a cooling medium for cooling elements of the tuyere device, and the heating of natural gas is carried out stepwise, sequentially passing it through the cooling cavities of the cooled elements of the tuyere device and heating the gas at each stage for 50-150 ° C.

Significant disadvantages of this method of supplying natural gas to a blast furnace are:

- reduced productivity of the blast furnace due to the lack of the ability to switch and regulate the thermal regime;

- the occurrence of emergency situations associated with the cooling of the elements of the tuyere device when closing natural gas at the time of blowing and stopping the blast furnace;

- increased consumption of carbon-containing materials associated with the need to control the thermal regime of the blast furnace by changing the temperature of the blast.

It is also known a device for supplying natural gas to a blast furnace, containing a distribution manifold connected to the hollow flanges of the movable elbow of the tuyere device, in which, for the purpose of heating the gas, the hollow flange of the movable elbow is connected by a pipeline to the gas supply channel to the tuyere [2].

Significant disadvantages of this device for supplying natural gas to a blast furnace are:

- low productivity of the blast furnace in connection with the impossibility of a quick impact on its thermal regime;

- emergence of emergency situations in case of depressurization of elements of the tuyere device cooling by natural gas;

- insufficient heating of natural gas due to the irrational use of heat to cool adjacent water-cooled elements of the tuyere device.

There is also a method of producing pig iron, which includes the production of hot reducing gas by gasification of coal or carbon-containing materials in a liquid bath using oxygen-enriched blast and blowing the obtained hot reducing gas into a blast furnace, in which oxygen enriched blasting up to 55- is used for gasification 60%, and a concentrate of iron ore or other oxidized metal-containing materials, and the resulting hot reducing gas is blown into the tuyeres of the blast furnace accordingly 0.8-0.9 thousand m ³ / t of pig iron and at the same time oxygen in the ratio of 0.15-0.17 thousand m ³ / t of pig iron, and additionally 0.18-0 cast iron is obtained in the liquid bath , 21 t / g of pig iron of a blast furnace [3].

Significant disadvantages of this method of producing pig iron are:

- high costs for the construction of coal gasification;

- the high cost of pig iron due to the need to use a large amount of oxygen;

- low productivity of the blast furnace due to violation of the thermal regime of blast furnace smelting with slight fluctuations in the chemical composition of the charge materials.

The desired technical results of the invention are:

- increase the productivity of the blast furnace;

- reduction in the consumption of carbon-containing materials;

- reduction of water consumption for cooling elements of the tuyere device;

- improving the reliability of the cooled elements of the tuyere device.

To this end, a method is proposed for cooling the elements of the tuyere device of a blast furnace, including heating natural gas by supplying it as a cooling medium for cooling the elements of the tuyere device by means of a bypass connecting pipe located between the tuyere device and the collector of natural gas supply, in which natural gas is used as a cooling medium is supplied at a pressure of 3-12 kg / cm ² at a rate of up to 1000 m ³ / hour, and at the moment of blowing and stopping the blast furnace as a cooling medium is fed under nitrogen and lenii 3-12 kg / cm ² at a rate of 50-800 m ³ / h.

The claimed limits are selected experimentally.

The pressure of natural gas and nitrogen is chosen based on the fact that at a pressure of less than 3 kg / cm ^{2 the} minimum permissible pressure difference is not ensured; natural gas (nitrogen) is a hot blast, and at a pressure of more than 12 kg / cm ² it is possible to destroy gas pipelines of natural gas and nitrogen .

The consumption of natural gas through the bypass connecting pipe is determined by the change in the thermal regime of the blast furnace, in which, if the flow rate exceeds 1000 m ³ / h, the distribution of natural gas over the tuyeres of the blast furnace is uneven and the gas-dynamic flow is disturbed.

The nitrogen flow rate for cooling the elements of the tuyere device at the time of blasting and stopping the blast furnace is selected based on the fact that at a flow rate of less than 50 m ³ / h, cooling is insufficient and burnout of the cooling element is possible, and at a flow rate of more than 800 m ³ / h, nitrogen is misused .

The inventive method of cooling the elements of the tuyere device of a blast furnace was implemented on a blast furnace with a volume of 1719 m ³ . On this blast furnace, 16 tuyere devices were installed according to the scheme (see drawing). At the time of shutdown and during the blasting period of the blast furnace, the elements of the tuyere device were cooled with nitrogen at a pressure of 3-12 kg / cm ² with a flow rate of 50-800 m ³ / h. After the furnace was blown up, the nitrogen supply for cooling the elements of the tuyere device was stopped and natural gas was supplied at a pressure of 3-12 kg / cm ² with a flow rate of 0-1000 m ³ / h, which was separated by the bypass connecting pipe as the blast furnace was under thermal conditions.

The conduct of blast furnace smelting according to the claimed method allowed to increase the productivity of the blast furnace by 0.9%, reduce the consumption of carbon-containing materials by 4.2 kg / t of cast iron, reduce the consumption of water for cooling water-cooled elements of the tuyere device by 16 m ³ / h and increase their resistance by 30 days

Information sources

1. RF patent No. 2294377, C21B 5/00.

2. A.s. No. 399525, cl. C21B 7/16.

3. RF patent No. 2277127, C21B 5/00.

Claims (1)

A method of cooling elements of the tuyere device of a blast furnace, including heating natural gas by supplying it as a cooling medium for cooling the elements of the tuyere device by means of a bypass connecting pipe located between the tuyere device and the collector of natural gas supply, characterized in that natural gas is supplied as a cooling medium at a pressure of 3-12 kg / cm ² at a rate of 1000 m ³ / h, and at the time of blowing and stopping the depressurization of the blast furnace at the tuyere assembly elements as oh azhdayuschey medium supplied nitrogen at a pressure of 3-12 kg / cm ² at a rate of 50-800 m ³ / h.

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