RU2191830C1 - Blast furnace air tuyere - Google Patents

Abstract

FIELD: ferrous metallurgy. SUBSTANCE: air tuyere has steel flange, inner and outer sleeves and tuyere copper nose, which are hermetically connected one with another and whose internal surfaces define blowing channel, pipe for supplying natural gas to internal sleeve pipe. Tuyere copper nose internal surface is equipped with step. Gas supplying pipe has igniter tube with internal diameter making 0.12-0.26 of internal diameter of gas supplying pipe. Igniter tube is connected to blowing channel and is hermetically fixed on internal sleeve at distance from tuyere flange equal to 0.2-2.0 of internal sleeve diameter. Air tuyere of such construction is used in the process of melting cast iron in blast furnace for blowing fuel additives. EFFECT: increased efficiency and reduced coke formation by increased extent of fuel usage. 1 dwg, 1 tbl

Description

 The invention relates to ferrous metallurgy, in particular to blast furnace production, and can be used in the smelting of cast iron in blast furnaces with injection of fuel additives.

 Known air tuyere of a blast furnace, including a flange, copper inner and outer cups and the nose connected tightly, and the inner glass and the nose of the tuyere create a blast channel. A tube was introduced into the upper part of the blow channel for supplying natural gas to the center of the blow stream (SU 1177349, С 21 В 7/16, 1985).

 The known lance design provides the best degree of mixing of natural gas with blast, contributes to its better burning in the tuyere hearth and helps to reduce the consumption of coke in the blast furnace process.

 A disadvantage of the known design of an air lance is that with a high-temperature and oxygen-enriched blast, the natural gas supply pipe burns out and loses its positive functions.

 Closest to the invention, the technical solution for the achieved result is the known design of an air lance of a blast furnace, including a flange, copper outer and inner glasses and the nose of the lance connected tightly, the inner surfaces of the inner glass and the nose of the lance forming a blast channel of variable cross section (RU 2150511, C 21 B 7/16, 1999).

 This design also leads to improved mixing of natural gas with blast in the tuyere zone.

 The disadvantage of this design is that with the properties of natural gas as a light hydrocarbon fuel, it ignites later and the combustion reaction moves to the zone of the tuyere source with a lack of oxygen.

 The technical result of the present invention is to eliminate the disadvantage of analogue and prototype, improving the conditions of the combustion reaction of natural gas by providing an early stage of the beginning of the combustion reaction, completion of complete combustion in the tuyere, improving the degree of use of hydrocarbon fuel and reducing coke consumption.

 The specified technical result is achieved by the fact that the air lance of the blast furnace, which includes a steel flange hermetically connected to each other, inner and outer cups, a copper sock located in the inner cavity between the outer and inner cups, a gas supply pipe for supplying natural gas to a blowing channel of variable cross section, formed the inner surfaces of the steel flange, inner cup and copper toe having a ledge on the inner surface, and the gas supply pipe is equipped with an ignition pipe a substitute tightly mounted on the inner cup at a distance from the steel flange equal to 0.2-2.0 of the diameter of the inner cup, while the inner diameter of the ignition tube is 0.12-0.26 of the inner diameter of the gas supply tube.

 The indicated limits of the ratio of the size of the igniter tube and its location from the lance flange are established experimentally and provide the best course of the combustion reaction of natural gas.

 The invention is illustrated in the drawing, which shows a longitudinal section of an air lance of a blast furnace.

 The lance includes a steel flange 1, a copper outer cup 2, which can be made of steel, a copper inner cup 3, which can be made of steel, and also coated with a refractory lining, a copper sock 4, interconnected hermetically by welding 9.

Through the internal cavity 11, between the outer and inner copper or steel cups of the tuyere, a gas supply pipe 5 passes, through the outlet 6 of which natural gas enters the blast stream. At a distance L from the steel flange of the lance equal to 0.2-2.0 of the diameter of the inner copper or steel cup d ₁ , the igniter tube 7 with an inner diameter d ₂ equal to 0.12-0 leaves and connects to the blast flow , 26 of the inner diameter d _{3 of the} gas supply tube 5. On the inner surface of the copper toe 4 of the lance, a ledge 8, d _{4 is made} . The blast channel 10 is formed by the inner surfaces of the steel flange 1, a copper or steel cup 3, which can be coated with a refractory lining and a copper toe 4. The diameter of the inner surface of the flange 1 and the cup 3, a copper toe 4 create a blast channel of variable cross-section, because d _{4 is} less than d ₂ by the magnitude of the step 8.

 An air lance according to the invention operates as follows.

Through the lance flange 1, a stream of blast heated to a temperature of 900-1200 ^{° C.} enters the blast channel 10. An insignificant volume of gas flows from the igniter tube 7 into the blast channel 10, which immediately ignites due to a large excess of highly heated blast. The burning gas leaving the igniter tube is mixed with the main stream of gas entering the blast through the tube 5 through the outlet 6. In this case, due to the flame in the igniter, most of the gas ignites immediately upon exiting the gas supply tube. On ledge 8, during high-speed movement of the gas-blast mixture, the flow slows down and swirls, which contributes to better mixing and complete completion of the combustion of natural gas in the tuyere.

 Example. To select the optimal diameter of the igniter tube and determine the place of supply of the igniter tube to the blast channel, experimental tuyeres were installed on a blast furnace.

 Experiment A.

Эксперимент В.The process of burning natural gas in a lance at
d ₃ - 27.33 mm, d ₂ - 2.7, 6.0 mm

Experiment B.

Результаты экспериментов приведены в таблице.The process of burning natural gas in a lance at
L - 110, 370 mm d ₁ - 160, 180 mm

The experimental results are shown in the table.

When the ratio of the diameters of the igniter tube and the diameter of the main supply tube of natural gas as claimed in the invention, as well as the structural arrangement of the igniter tube in the tuyere, efficient mixing of natural gas with blast, its complete combustion in the tuyere channel is ensured, due to this, the coefficient of coke replacement with natural gas increases 0.03-0.06 kg of coke / m ³ natural gas.

Claims (1)

 An air tuyere of a blast furnace, including a steel flange hermetically connected together, an inner and outer cup, a copper sock located in the inner cavity between the outer and inner cups, a gas supply pipe for supplying natural gas to the blast channel formed by the inner surfaces of the steel flange, inner cup, and copper a toe having a step on the inner surface, characterized in that the gas supply tube is provided with an igniter tube sealed to the inner stack not at a distance from the steel flange equal to 0.2-2.0 of the diameter of the inner cup, while the inner diameter of the igniter tube is 0.12-0.26 of the inner diameter of the gas supply tube.

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