阅读说明：本技术 一种多级燃烧器、一种钢水罐预热设备及其使用方法 (Multi-stage burner, molten steel tank preheating equipment and using method thereof ) 是由 王勇 刘前芝 尹丰 胡以元 袁东明 鲍磊 张仕洋 孙波 牛金印 于 2019-09-29 设计创作，主要内容包括：本发明涉及钢水罐预热设备领域,具体来说是一种多级燃烧器、一种钢水罐预热设备及其使用方法,所述燃烧器包括燃烧器本体,所述燃烧器本体上设有用于气体进入的进气管道；所述燃烧器本体上设有用于燃气和氧气燃烧的燃烧室；所述燃烧室包括燃烧室喷口,所述燃烧室喷口与燃烧器本体外侧面相连通；所述燃烧器本体上设有用于点火的点火枪。本发明公开了一种多级燃烧器结构,通过燃烧器的结构优化,并且本发明采用纯氧气纯氧代替空气作为助燃介质,减少了空气中的氮气和惰性气体的参与热量交换所造成的热量损失,系统热效率和钢水罐升温速度均会大幅提高。(The invention relates to the field of molten steel tank preheating equipment, in particular to a multistage burner, molten steel tank preheating equipment and a using method thereof, wherein the burner comprises a burner body, and an air inlet pipeline for air to enter is arranged on the burner body; the combustor body is provided with a combustion chamber for combusting gas and oxygen; the combustion chamber comprises a combustion chamber nozzle which is communicated with the outer side surface of the combustor body; and the combustor body is provided with an ignition gun for ignition. The invention discloses a multi-stage burner structure, which is optimized through the structure of the burner, adopts pure oxygen instead of air as a combustion-supporting medium, reduces the heat loss caused by the participation of nitrogen and inert gas in the air in heat exchange, and greatly improves the system heat efficiency and the temperature rising speed of a molten steel tank.)

1. The multistage burner is characterized by comprising a burner body, wherein an air inlet pipeline for air to enter is arranged on the burner body; the combustor body is provided with a combustion chamber for combusting gas and oxygen; the combustion chamber comprises a combustion chamber nozzle which is communicated with the outer side surface of the combustor body; the combustor body is provided with an ignition gun for ignition; one end of the ignition gun is positioned in the combustor body, and the other end of the ignition gun extends to the combustion chamber; the gas inlet pipeline comprises a gas inlet pipeline and a flame stabilizing gas inlet pipeline; the gas inlet pipeline and the flame stabilizing inlet pipeline are communicated with the combustion chamber.

2. The multi-stage burner of claim 1, wherein the burner body has a plurality of multi-stage oxygen nozzles disposed along a periphery of the combustion chamber.

3. The multi-stage burner of claim 1, wherein the burner body comprises a combustion end and an air inlet end, the combustion end comprises a combustion end housing having an end connected to the air inlet end, and a burner protection brick layer is disposed in the combustion end housing; the combustor protection brick layer is provided with a combustion chamber for mixing fuel gas and oxygen; nozzles for multi-stage oxygen to enter are further arranged on the two sides of the combustion protection brick layer; the nozzle is disposed through the combustor protective layer.

4. The multi-stage burner of claim 1, wherein the inlet end includes an inlet end outer housing coupled to a combustion end outer housing; the inner part of the air inlet end outer shell is hollow; the gas inlet pipeline and the flame stabilizing gas inlet pipeline penetrate through the outer shell of the gas inlet end and are communicated with the combustion chamber; and a multi-stage oxygen inlet for multi-stage oxygen to enter is formed in the outer shell of the air inlet end.

5. The multi-stage burner of claim 4, wherein the inlet end outer housing further comprises an air inlet for air to enter.

6. The multi-stage burner of claim 1, wherein a divider plate is disposed within the outer shell, the divider plate dividing the inner cavity of the outer shell into an upper chamber and a lower chamber; the partition plate is provided with a plurality of communicating holes for communicating.

7. A molten steel ladle preheating apparatus using the multi-stage burner as set forth in any one of claims 1 to 8, wherein the preheating apparatus comprises a placing device for placing a molten steel ladle, the placing device comprising a placing arm for placing a ladle cover; the preheating device also comprises a preheating device arranged on a ladle cover in the molten steel tank to be preheated, and the preheating device comprises a multi-stage combustor for mixed combustion of gas and oxygen; the multistage burner is connected with a gas supply mechanism for supplying gas to the molten steel tank; the gas supply mechanism comprises a gas supply part and an oxygen supply part; the gas supply part comprises a gas supply pipeline; the oxygen supply part comprises an oxygen supply pipeline.

8. The apparatus for preheating a molten steel ladle according to claim 1, wherein the gas supply means further comprises a nitrogen gas supply part for purging; the nitrogen gas supply part comprises a nitrogen gas supply pipeline; the nitrogen gas supply pipeline is respectively communicated with the fuel gas supply pipeline and the oxygen gas supply pipeline.

9. The apparatus of claim 1, wherein the oxygen supply line comprises a branch line assembly connected to the flame holding gas supply line and the multi-stage oxygen supply line; the branch pipeline assembly comprises a flame-stabilizing oxygen pipeline and a multi-stage oxygen pipeline; the flame stabilizing oxygen pipeline is communicated with a flame stabilizing air inlet pipeline on the multi-stage combustor; the multi-stage oxygen pipeline is communicated with a multi-stage oxygen inlet pipeline on the multi-stage combustor.

10. Use of a preheating device for steel ladles according to any of claims 7 to 9, characterized in that it comprises the following steps:

A. firstly, limiting the air inflow of each pipeline by adjusting the flow control valve group 18; after the adjustment is finished and before the molten steel tank is preheated, nitrogen is supplied to the molten steel tank, and the whole preheating equipment and the molten steel tank are cleaned by using the nitrogen;

B. after the step (A) is finished, performing gas supply operation on the molten steel tank, supplying oxygen to the multistage burner 1 through an oxygen gas supply pipeline 20, and supplying gas to the multistage burner 1 through a gas supply pipeline 21; oxygen enters the flame stabilizing air inlet pipeline 5 through the flame stabilizing oxygen pipeline 201 and enters the combustion chamber 3 through the flame stabilizing air inlet pipeline 5; oxygen enters the interior of the multi-stage combustor 1 through a multi-stage oxygen pipeline 202; the fuel gas enters the combustion chamber 3 through a fuel gas inlet pipeline 4; the flame-stabilizing oxygen entering the combustion chamber 3 is mixed with the fuel gas, and the multi-stage oxygen enters the molten steel tank through the nozzle 8 to be mixed with the flue gas in the molten steel tank; controlling the flow of fuel gas and oxygen on a visual operation panel on a combustion control system 23 according to feedback signals and operation requirements, wherein the oxygen is divided into flame-stabilizing oxygen and multi-stage oxygen through a branch pipeline assembly, and the flame-stabilizing oxygen and the multi-stage oxygen respectively enter a multi-stage combustor 1 and enter a molten steel tank for combustion reaction;

C. the gas and the flame-stabilizing oxygen are mixed in a premixing cavity 31 of the multi-stage combustor 1 and undergo a primary combustion reaction, the temperature in the premixing cavity 31 is increased, the gas volume is rapidly expanded to form high-temperature airflow clusters, and the high-temperature airflow clusters are ejected out of the combustor at a high speed through a combustor nozzle with a reverse necking to form stable flames to enter a hearth; the multi-stage oxygen enters the molten steel tank through the multi-stage oxygen nozzle 8 at a gas flow rate close to the sound velocity, the multi-stage oxygen nozzle 8 and the nozzle 32 of the combustion chamber have a certain distance, the multi-stage oxygen contacts the flue gas in the molten steel tank before contacting and reacting with the fuel gas, the high momentum oxygen is rapidly mixed with the flue gas and then is combusted, so that the molten steel tank is rapidly heated; the speed of a nozzle of the burner is adjusted by adjusting the flow of the flame-stabilizing oxygen and controlling the temperature in the premixing chamber, so that the functions of controlling and adjusting the length and the shape of flame are achieved;

D. repeating the steps (B) to (C) until the temperature of the molten steel tank reaches the set requirement; and stopping the supply of fuel gas and oxygen after the molten steel tank reaches the set requirement.

Technical Field

The invention relates to the field of molten steel tank preheating equipment, in particular to a multistage burner, molten steel tank preheating equipment and a using method thereof.

Background

At present, the preheating of a molten steel tank mainly has the following problems: the flame of the current air combustion-supporting baking burner has no rigidity, the flame is mainly concentrated on the upper half part of the molten steel tank, the heat cannot be effectively transferred to the bottom of the molten steel tank, and the temperature uniformity in the ladle is poor; according to the information feedback of field operators, the average baking temperature of the current molten steel tank is about 600 ℃, the heat storage capacity in the ladle is low, and the temperature of the molten steel is greatly reduced after the molten steel is put into the ladle, so the requirement on the tapping temperature is high; the baking operation time of the turnover molten steel tank is long, so that the turnover bags are numerous; the number of turnover molten steel tanks participating in production is as large as 30, and the capital occupation, the maintenance cost and the management cost are high.

Therefore, a novel molten steel tank preheating device is needed at present.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a multi-stage burner for a molten steel tank preheating device.

In order to achieve the purpose, the invention adopts the technical scheme that:

a multi-stage combustor comprises a combustor body, wherein an air inlet pipeline for air to enter is arranged on the combustor body; the combustor body is provided with a combustion chamber for combusting gas and oxygen; the combustion chamber comprises a combustion chamber nozzle which is communicated with the outer side surface of the combustor body; the combustor body is provided with an ignition gun for ignition; one end of the ignition gun is positioned in the combustor body, and the other end of the ignition gun extends to the combustion chamber; the gas inlet pipeline comprises a gas inlet pipeline and a flame stabilizing gas inlet pipeline; the gas inlet pipeline and the flame stabilizing inlet pipeline are communicated with the combustion chamber.

The combustor is characterized in that a plurality of multistage oxygen nozzles are arranged on the combustor body and arranged along the periphery of the combustion chamber.

The combustor body comprises a combustion end and an air inlet end, the combustion end comprises a combustion end shell of which the end part is connected with the air inlet end, and a combustor protective brick layer is arranged in the combustion end shell; the combustor protection brick layer is provided with a combustion chamber for mixing fuel gas and oxygen; nozzles for multi-stage oxygen to enter are further arranged on the two sides of the combustion protection brick layer; the nozzle is disposed through the combustor protective layer.

The air inlet end comprises an air inlet end outer shell connected with the combustion end outer shell; the inner part of the air inlet end outer shell is hollow; the gas inlet pipeline and the flame stabilizing gas inlet pipeline penetrate through the outer shell of the gas inlet end and are communicated with the combustion chamber; and a multi-stage oxygen inlet for multi-stage oxygen to enter is formed in the outer shell of the air inlet end.

And an air inlet for air to enter is also formed in the air inlet end outer shell.

A partition plate is arranged in the outer shell and divides the inner cavity of the outer shell into an upper cavity and a lower cavity; the partition plate is provided with a plurality of communicating holes for communicating.

A molten steel tank preheating device adopting a multi-stage burner comprises a placing device for placing a molten steel tank, wherein the placing device comprises a placing large arm for placing a molten steel tank cover; the preheating device also comprises a preheating device arranged on a ladle cover in the molten steel tank to be preheated, and the preheating device comprises a multi-stage combustor for mixed combustion of gas and oxygen; the multistage burner is connected with a gas supply mechanism for supplying gas to the molten steel tank; the gas supply mechanism comprises a gas supply part and an oxygen supply part; the gas supply part comprises a gas supply pipeline; the oxygen supply part comprises an oxygen supply pipeline.

The gas supply device also comprises a nitrogen gas supply part for cleaning; the nitrogen gas supply part comprises a nitrogen gas supply pipeline.

The nitrogen gas supply pipeline is respectively communicated with the fuel gas supply pipeline and the oxygen gas supply pipeline.

The oxygen gas supply pipeline is connected with the flame-stabilizing gas inlet pipeline and the multistage oxygen gas inlet pipeline through branch pipeline components; the branch pipeline assembly comprises a flame-stabilizing oxygen pipeline and a multi-stage oxygen pipeline; the flame stabilizing oxygen pipeline is communicated with a flame stabilizing air inlet pipeline on the multi-stage combustor; the multi-stage oxygen pipeline is communicated with a multi-stage oxygen inlet pipeline on the multi-stage combustor.

The invention has the advantages that:

the invention discloses a multi-stage burner structure, which is optimized through the structure of the burner, adopts pure oxygen instead of air as a combustion-supporting medium, reduces the heat loss caused by the participation of nitrogen and inert gas in the air in heat exchange, and greatly improves the system heat efficiency and the temperature rising speed of a molten steel tank; according to the invention, through the structural optimization of the multistage gas burner, oxygen and gas are respectively sprayed out through different burner nozzles, and in the combustion process, high-momentum oxygen-gas jet flow and gas in the tank are subjected to entrainment mixing and then are combusted, so that the combustion is stable, the flame is uniform and dispersed, the uniform distribution and heat transfer of temperature are promoted, the peak temperature is effectively reduced, and the generation of hot spots in the tank is reduced.

Drawings

The following is a brief description of the various views of the present specification:

FIG. 1 is a schematic view of a multi-stage combustor.

FIG. 2 is a schematic view showing the construction of a molten steel ladle preheating apparatus using multi-stage burners.

Fig. 3 is a schematic view showing the arrangement of the air supply mechanism in the present invention.

Detailed Description

The following description of preferred embodiments of the invention will be made in further detail with reference to the accompanying drawings.

A multi-stage combustor 1 comprises a combustor body, wherein an air inlet pipeline for air to enter is arranged on the combustor body; the combustor body is provided with a combustion chamber 3 for combusting gas and oxygen; the combustion chamber 3 comprises a combustion chamber nozzle 32, and the combustion chamber nozzle 32 is communicated with the outer side surface of the burner body; the combustor body is provided with an ignition gun 2 for ignition; one end of the ignition gun 2 is positioned in the combustor body, and the other end of the ignition gun extends to the combustion chamber 3; the gas inlet pipeline comprises a gas inlet pipeline 4 and a flame stabilizing gas inlet pipeline 5; the gas inlet pipeline 4 and the flame stabilizing gas inlet pipeline 5 are communicated with the combustion chamber 3; the invention discloses a multistage burner 1, wherein a burner body is inserted into a water inlet of a molten steel tank; the combustion chamber 3 is used for mixing fuel gas and oxygen to form mixed gas, and the ignition gun 2 is used for igniting the mixed gas in the combustion chamber 3 through the arrangement of the ignition gun 2, wherein the combustion chamber 3 comprises a combustion chamber nozzle 32 and a premixing cavity 31; the premixing cavity 31 is communicated with the interior of the molten steel tank through a nozzle 32 of the combustion chamber; the gas entering the multi-stage combustor 1 through the gas inlet pipeline 4 is mixed with the oxygen entering the flame stabilizing gas inlet pipeline 5 in the premixing cavity 31 and is ignited by the ignition gun 2 to generate a primary combustion reaction, the temperature in the premixing cavity 31 is increased, the gas volume is rapidly expanded to form high-temperature airflow clusters, and the high-temperature airflow clusters are ejected out of the multi-stage combustor 1 at a high speed through the nozzle 32 of the combustion chamber; in order to better ensure the injection of flame, the nozzle is in a frustum shape in the combustion process, namely the opening size of one end close to the molten steel tank is smaller than that of the other end far away from the molten steel tank; the nozzle 32 of the combustion chamber is of an inverted-contraction structure, and the nozzle of the combustor is ejected out of the combustor at a high speed to form stable flame to enter a hearth.

Preferably, the burner body is provided with a plurality of multi-stage oxygen nozzles 8, and the multi-stage oxygen nozzles 8 are arranged along the periphery of the combustion chamber 3; oxygen enters the interior of the multi-stage combustor 1 through the multi-stage oxygen inlet 6, the oxygen entering the interior of the multi-stage combustor 1 enters the molten steel tank through the multi-stage oxygen nozzle 8, the oxygen can enter the molten steel tank at a gas flow rate close to the sound speed due to the size of the nozzle 8, and the multi-stage oxygen nozzle 8 and the combustion chamber nozzle 32 are spaced at a certain distance, so that the multi-stage oxygen firstly contacts with flue gas in the molten steel tank before contacting and reacting with the fuel gas, high-momentum oxygen is quickly mixed with the flue gas, and the oxygen is combusted again after being mixed with the flue gas, so that the temperature in the molten steel tank can be increased, and the temperature rise speed of the molten steel tank; the amount of oxygen entering the molten steel tank in the invention needs to be controlled according to requirements, so that the combustion is stable, but the flame peak temperature is lower than the highest temperature capable of being borne by the refractory material, the generation of hot spots in the molten steel tank is effectively reduced, and the refractory material on the molten steel tank is effectively protected.

Preferably, the burner body comprises a burning end and an air inlet end, the burning end comprises a burning end shell 11 of which the end part is connected with the air inlet end, and a burner protection brick layer 7 is arranged in the burning end shell 11; the combustor protective brick layer 7 is provided with a combustion chamber 3 for mixing fuel gas and oxygen; nozzles 8 for multi-stage oxygen to enter are further arranged on the two sides of the combustion protection brick layer; the nozzle 8 penetrates through the combustor protective layer; the combustion end is mainly used for realizing the functions of combustion and oxygen entering the molten steel tank; the inlet end is mainly used for oxygen supply to the multi-stage burner 1 and the ladle.

Preferably, the intake end of the present invention includes an intake end outer housing 10 connected to a combustion end outer housing 11; the air inlet end outer shell 10 is hollow; the gas inlet pipeline 4 and the flame stabilizing gas inlet pipeline 5 penetrate through the gas inlet end outer shell 10 and are communicated with the combustion chamber 3; the air inlet end outer shell 10 is provided with a multi-stage oxygen inlet 6 for multi-stage oxygen to enter; the multi-stage oxygen inlet 6 is used for enabling oxygen to enter the multi-stage combustor 1, and enabling the oxygen entering the multi-stage combustor 1 to enter the molten steel tank through the nozzle 8 again, so that the oxygen is mixed with smoke in the molten steel tank, reheating of the molten steel tank is achieved, and the temperature rising speed of the molten steel tank can be improved; the intake end may be externally connected to the combustion end housing 11 via attachment flanges 10-11.

In order to ensure the air flow smoothness of the whole device, the cover of the molten steel tank is provided with an exhaust hole which is connected with an exhaust pipe, and the exhaust pipe is used for exhausting flue gas fully combusted in the molten steel tank so as to avoid the accumulation of the flue gas in the molten steel tank; of course, the emission of the flue gas in the molten steel tank can be realized through other structures.

Preferably, the air inlet end outer shell 10 is further provided with an air inlet 9 for air to enter; the air inlet 9 is arranged, so that the multi-stage combustor 1 disclosed by the invention can heat a molten steel tank by using pure oxygen; the air can be used for heating the molten steel tank, so that the invention has wider use effect, and different heating speeds can be selected according to requirements to heat the molten steel tank; an air inlet pipe 221 is connected to the air inlet 9, and a blower 22 is connected to the end of the air inlet pipe 221.

Preferably, a partition plate 12 is arranged in the outer shell, and the inner cavity of the outer shell is divided into an upper cavity 61 and a lower cavity 91 by the partition plate 12; a plurality of communicating holes for communicating are formed in the partition plate 12; the partition plate 12 is arranged so that the outer body is divided into two chambers, so that the whole device; can be used for storing a part of oxygen or air, and simultaneously plays a role of buffering to avoid generating larger fluctuation when gas is supplied.

A molten steel tank preheating device adopting a multistage burner 1 comprises a placing device for placing a molten steel tank, wherein the placing device comprises a placing large arm 15 for placing a molten steel tank cover 101; the preheating device also comprises a preheating device arranged on a ladle cover in the molten steel tank to be preheated, and the preheating device comprises a multi-stage combustor 1 for mixed combustion of gas and oxygen; the multi-stage combustor 1 is connected with an air supply mechanism for supplying air to a molten steel tank; the gas supply mechanism comprises a gas supply part and an oxygen supply part; the gas supply part comprises a gas supply pipeline 21; the oxygen supply means comprises an oxygen supply conduit 20; the molten steel tank preheating equipment mainly comprises a placing device, wherein the placing device is used for placing the molten steel tank, the multi-stage combustor 1 is used for mixing fuel gas and oxygen to play a main combustion role, the multi-stage oxygen enters the molten steel tank, and the multi-stage oxygen is mixed with flue gas in the molten steel tank to play a reheating role, so that the temperature rise of the molten steel tank is accelerated; the gas supply mechanism is used for supplying gas to the multi-stage combustor 1 and providing energy for heating the molten steel tank.

Preferably, the gas supply device in the invention further comprises a nitrogen gas supply part for cleaning; the nitrogen gas supply part comprises a nitrogen gas supply pipeline 19; the nitrogen gas supply part plays a role of primary exhaust and is used for cleaning residual air, oxygen, fuel gas and the like in the multistage burner 1 and the molten steel tank so as to reduce the risk of explosion.

Preferably, in the present invention, the nitrogen gas supply pipeline 19 is respectively communicated with a fuel gas supply pipeline 21 and an oxygen gas supply pipeline 20; by such an arrangement, the arrangement of the nitrogen gas supply pipe 19 is simplified, and the mess of the pipe is avoided.

Preferably, the oxygen gas supply pipeline comprises a branch pipeline assembly connected with the flame-stabilizing gas supply pipeline 5 and a multi-stage oxygen gas supply pipeline; the branch line assembly comprises a flame holding oxygen conduit 201 and a multi-stage oxygen conduit 202; the flame stabilizing oxygen pipeline 201 is communicated with a flame stabilizing air inlet pipeline 5 on the multi-stage combustor 1; the multistage oxygen pipeline 202 is communicated with a multistage oxygen inlet pipeline on the multistage burner 1; through the arrangement of the branch pipeline assembly, the oxygen in the oxygen supply pipeline is divided into two paths of gas, and the aim of the invention can be better realized.

The invention belongs to a special device for preheating a molten steel tank in steelmaking and refining production, and mainly converts a traditional combustion system of air combustion-supporting low-calorific-value gas into an oxygen combustion-supporting system, and utilizes surplus oxygen resources to achieve the purposes of improving the combustion temperature and the combustion efficiency, improving the baking end point temperature of the molten steel tank, reducing the tapping temperature, accelerating the heating rate, reducing the number of turnover molten steel tanks, saving fuel, greatly reducing the smoke gas amount, reducing the emission of nitrogen oxides and the like.

The multi-stage burner 1 and the molten steel tank preheating device disclosed by the invention are used; the temperature rise control can be accurately carried out according to the temperature rise curve required by the refractory material, and the temperature rise end point temperature is as high as 900-; compared to conventional air-fuel combustion, oxygen combustion has many advantages because it eliminates the adverse effects of nitrogen on the combustion process: the heat transfer and the heat transfer control are enhanced, and the heat efficiency is high; the fuel consumption is reduced; increase the melting rate/heating efficiency; reduced pollutant emissions (clean and complete combustion), reduced flue gas volume (up to 70%); the maintenance and the operation are simple, and the cost is low; the equipment investment is low, for example, the cost of the waste gas treatment device and the cost of the flue gas waste heat recovery device can be reduced;

in addition, the invention has simple structural principle, namely, the traditional combustion system of air combustion-supporting low-calorific-value gas is converted into an oxygen combustion-supporting system, and the surplus oxygen resources are utilized to improve the combustion temperature and the combustion efficiency, thereby realizing the purposes of improving the baking end point temperature of the molten steel tank, reducing the tapping temperature, accelerating the heating rate, reducing the number of turnover molten steel tanks and saving fuel.

In order to more clearly express the content of the invention, the invention is discussed below with reference to the attached drawings;

a molten steel tank preheating device adopting a multistage burner 1 comprises a placing device for placing a molten steel tank, wherein the placing device comprises a placing large arm 15 for placing a molten steel tank cover 101; the preheating device also comprises a preheating device arranged on a ladle cover in the molten steel tank to be preheated, and the preheating device comprises a multi-stage combustor 1 for mixed combustion of gas and oxygen; the multi-stage combustor 1 is connected with an air supply mechanism for supplying air to a molten steel tank; the gas supply mechanism comprises a gas supply part and an oxygen supply part; the gas supply part comprises a gas supply pipeline 21; the oxygen supply means comprises an oxygen supply conduit 20; the placing device is connected with a lifting mechanism 151; the molten steel tank preheating equipment also comprises a flow control valve group 18; flow control valves 18 is equipped with governing valve and flowmeter including setting up at nitrogen gas supply line 19, oxygen gas supply line 20, gas supply line 21, steady flame oxygen pipeline 201, multistage oxygen pipeline 202, and the governing valve is: an air branch electric control valve 181 or a gas branch electric control valve 183; the flow meter is as follows: an air manifold flow meter 182 or a gas manifold flow meter 184; the opening of each pipeline can be controlled by the arrangement of the regulating valve and the flowmeter, so that the control system can conveniently control the flow of gas in each pipeline in real time; in order to cooperate with the flow control valve set 18, the flow control valve set 18 may also include other components, such as a temperature sensor and a pressure gauge, which are mainly set as required; the invention is also provided with a combustion control system 23; the combustion control system 23 is conventionally controlled, and belongs to the known technology, the combustion control system 23 can be controlled by a computer or can be realized by other controllers, the lifting mechanism 151 comprises a winch 17, and the winch 17 can realize the height adjustment of the molten steel tank cover 101 by lifting and pressing the placing large arm 15; an insulation plate 16 is provided between the ladle cover 101 and the placing arm 15 to prevent damage of the apparatus by high temperature fumes.

The combustion control system 23(13) is connected with the flow control valve group 18 through 4-20 mA signals and 24VDC signals to realize the conveying and adjustment of pipeline gas, the operation of the lifting mechanism 151 of the molten steel tank cover 101 and the ignition control of the oxygen multi-stage combustor 1 can be realized on a visual operation panel, and the automatic operation condition of the device and the parameter changes of the pressure, the flow, the temperature and the like of each gas, oxygen and nitrogen are monitored in real time.

An infrared online thermometer 14 is pre-installed on the ladle cover 101, signals are transmitted to the combustion control system 23 through a special lead, and temperature changes are fed back on a visual operation panel in real time.

The flame detector 13 is fixedly arranged above the oxygen multi-stage combustor 1.

The combustor protective brick layer 7 is made of corundum-mullite castable.

A method of using a molten steel ladle preheating apparatus using a multistage burner 1, the method comprising:

A. firstly, limiting the air inflow of each pipeline by adjusting the flow control valve group 18; after the adjustment is finished and before the molten steel tank is preheated, nitrogen is supplied to the molten steel tank, and the whole preheating equipment and the molten steel tank are cleaned by using the nitrogen;

B. after the step (A) is finished, performing gas supply operation on the molten steel tank, supplying oxygen to the multistage burner 1 through an oxygen gas supply pipeline 20, and supplying gas to the multistage burner 1 through a gas supply pipeline 21; oxygen enters the flame stabilizing air inlet pipeline 5 through the flame stabilizing oxygen pipeline 201 and enters the combustion chamber 3 through the flame stabilizing air inlet pipeline 5; oxygen enters the interior of the multi-stage combustor 1 through a multi-stage oxygen pipeline 202; the fuel gas enters the combustion chamber 3 through a fuel gas inlet pipeline 4; the flame-stabilizing oxygen entering the combustion chamber 3 is mixed with the fuel gas, and the multi-stage oxygen enters the molten steel tank through the nozzle 8 to be mixed with the flue gas in the molten steel tank; controlling the flow of fuel gas and oxygen on a visual operation panel on a combustion control system 23 according to feedback signals and operation requirements, wherein the oxygen is divided into flame-stabilizing oxygen and multi-stage oxygen through a branch pipeline assembly, and the flame-stabilizing oxygen and the multi-stage oxygen respectively enter a multi-stage combustor 1 and enter a molten steel tank for combustion reaction;

C. the gas and the flame-stabilizing oxygen are mixed in a premixing cavity 31 of the multi-stage combustor 1 and undergo a primary combustion reaction, the temperature in the premixing cavity 31 is increased, the gas volume is rapidly expanded to form high-temperature airflow clusters, and the high-temperature airflow clusters are ejected out of the combustor at a high speed through a combustor nozzle with a reverse necking to form stable flames to enter a hearth; the multi-stage oxygen enters the molten steel tank through the multi-stage oxygen nozzle 8 at a gas flow rate close to the sound velocity, the multi-stage oxygen nozzle 8 and the nozzle 32 of the combustion chamber have a certain distance, the multi-stage oxygen contacts the flue gas in the molten steel tank before contacting and reacting with the fuel gas, the high momentum oxygen is rapidly mixed with the flue gas and then is combusted, so that the molten steel tank is rapidly heated; the speed of a nozzle of the burner is adjusted by adjusting the flow of the flame-stabilizing oxygen and controlling the temperature in the premixing chamber, so that the functions of controlling and adjusting the length and the shape of flame are achieved;

D. repeating the steps (B) to (C) until the temperature of the molten steel tank reaches the set requirement; and stopping the supply of fuel gas and oxygen after the molten steel tank reaches the set requirement.

The oxygen combustion adopts pure oxygen to replace air as a combustion-supporting medium, reduces the heat loss caused by the participation of nitrogen and inert gas in the air in heat exchange, and greatly improves the system heat efficiency and the temperature rise speed of the molten steel tank.

In a high-temperature environment such as baking of a ladle, radiation heat exchange is dominant. Diatomic gases such as air, oxygen, and nitrogen do not have the ability to emit and absorb radiant energy and can be considered as a transparent body for thermal radiation. And three-atom gases such as carbon dioxide and water vapor have great radiation capability.

In the flue gas generated by the air combustion-supporting mixed gas or coal gas, the content of triatomic gas with radiation capacity, namely carbon dioxide (CO2) and water vapor (H2O) is 31 percent; and the pure oxygen combustion-supporting flue gas has the content of CO2 and H2O of 76 percent. Therefore, the flame and the flue gas with pure oxygen combustion supporting have higher radiation heat exchange coefficient and stronger heat radiation capability, namely the radiation heat exchange efficiency is higher, which is also beneficial to the rapid temperature rise of the steel tank.

Due to the strong combustion-supporting characteristic of oxygen, the combustion reaction speed of gas or coal gas is very high, the flame temperature is high, short flame is formed, and the local temperature is extremely high; the baking of newly built cans such as overhaul cans cannot be met, and accidents such as baking burst of refractory materials and the like are easily caused. The device can effectively solve the problem, through theoretical calculation and simulation experiment, oxygen and gas or coal gas are designed to be respectively sprayed out through different burner nozzles 8, and in the combustion process, the high-momentum oxygen-fuel jet flow and gas in the tank are subjected to entrainment mixing and then are combusted, so that the combustion is stable, the flame is uniform and dispersed, the uniform distribution and heat transfer of the temperature are promoted, the peak temperature is effectively reduced, and the generation of hot spots in the tank is reduced.

It is clear that the specific implementation of the invention is not restricted to the above-described embodiments, but that various insubstantial modifications of the inventive process concept and technical solutions are within the scope of protection of the invention.