CN116237323A - A method for washing furnace with carbon deposits in hearth - Google Patents

Abstract

The invention relates to the technical field of furnace hearth accumulation and cleaning, and specifically discloses a furnace hearth carbon accumulation cleaning method, S1: adjusting the pressure in the hearth; S2: inserting a pulse double spray gun into the hearth according to a certain pulse sequence Pulse injection of oxygen and nitrogen; S3: The pulse pressure of the pulse double spray gun is greater than the pressure in the furnace hearth. When injecting oxygen and nitrogen, adjust the tuyere air pressure of the pulse double spray gun to keep the same as the furnace top pressure. Combining advanced full-oxygen smelting with blast furnace tuyere coal injection technology, a high-pressure oxygen pulse injection method is designed in the hearth according to a certain sequence through the tuyere coal injection technology to clean the hearth of carbon deposits.

Description

A method for washing furnace with carbon deposits in hearth

technical field

The application relates to the technical field of hearth accumulation cleaning, and specifically discloses a furnace hearth carbon accumulation cleaning method.

Background technique

Hearth accumulation is caused by long-term abnormality of a certain system in the blast furnace operation system or improper cooperation between several operating systems, as well as poor quality of raw materials and fuels. It seriously affects the reasonable distribution of hearth gas and the movement of furnace materials, reducing the hearth Safe Iron Capacity.

According to the accumulation position, it can be divided into hearth center accumulation and edge accumulation.

(1) The center of the hearth is piled up. Most of the accumulation in the center of the hearth is caused by the fact that the furnace material contains a lot of powder, the long-term gas distribution center is heavy, the lower wind speed and blast kinetic energy are small, and the turning area in front of the tuyere is too short. Symptoms of this kind of accumulation are: the initial performance is similar to the abnormal furnace condition with excessive development of marginal gas, but the total pressure difference is higher than that of simple marginal gas development. Due to the high pressure difference at the lower part, marginal pipes are prone to appear; the air pressure and air volume curves are sluggish ; The slag temperature is high but the FeO content in the slag is still higher than normal, the coke in front of the tuyere is not very active, and the slag is easy to flow and the tuyere is easy to be damaged.

(2) Accumulation on the edge of the hearth. It can be divided into three types: slag accumulation, graphite accumulation and slag iron accumulation with insufficient furnace temperature. Their symptoms are: the initial stage is similar to the abnormal furnace condition with excessive edge gas, the total pressure difference and the lower pressure difference increase and the wind pressure curve rises before slag and iron tapping, but decreases after slag and iron tapping, and the air volume is proportional to the wind pressure Reverse fluctuation, the material speed slows down before slag tapping and iron tapping, and significantly speeds up after tapping, the depth of the iron hole is deep, the tuyere is often damaged, and the lower part of the tuyere is easy to burn. When the local edge of the hearth is piled up, the tuyere damage in the stacking direction increases significantly.

The conventional method of dealing with accumulation on the edge of the hearth varies according to the cause of the accumulation.

The accumulation of slag is mainly caused by the high alkalinity of the slag. The economical and effective treatment method is to use acidic materials to reduce the alkalinity of the slag for cleaning. The amount of acidic materials added is determined by the degree of alkalinity higher than the normal value. It is to reduce the slag alkalinity of one furnace by 0.1~0.2. In order to ensure the quality of pig iron, it is not allowed to add several furnaces continuously. so far. Graphite accumulation is caused by long-term smelting of high-grade cast iron, especially in high-silicon and high-alkalinity smelting, which easily forms graphite accumulation.

The method of cleaning is to improve the fluidity of molten iron and control the formation of graphite, to refine steel or appropriately increase the manganese content of pig iron, which can achieve the purpose of cleaning this kind of accumulation. The accumulation of slag and iron with insufficient temperature is mostly caused by factors such as long-term wind shutdown, serious abnormality of furnace condition or long-term deviation, water leakage of cooling equipment, unsuitability of slagging system and thermal system, etc. To deal with this kind of accumulation, it is necessary to improve the fluidity of slag and iron and increase the heat of the hearth at the same time. Cleaning the hearth with fluorite can greatly improve the fluidity of the slag and is effective in dealing with hearth accumulation for various reasons. However, due to the serious erosion of the hearth by fluorite, it is generally only used when the accumulation is serious. .

To deal with the accumulation in the center of the hearth, the main method is to adjust the upper and lower operating systems, improve the air permeability of the central material column, and make the swivel area in front of the tuyere reach a reasonable depth. The specific method is: adjust the loading sequence and batch weight in the upper part to reduce the ore distribution in the center part; improve the quality of raw materials and fuels to improve the air permeability of the material column. The lower part appropriately increases the wind speed and blowing kinetic energy to improve the fluidity of the slag;

Later, we tested the pulverized coal injection at the tuyere of the Ouyeel furnace. Due to the state of the hearth, we failed. Mature fuel adjustment and hearth adjustment technology, for this reason, we put forward the concept of combining the Ouyeel furnace's full-oxygen smelting with the blast furnace's tuyere coal injection technology, and propose a new furnace hearth carbon accumulation cleaning method.

Contents of the invention

The purpose of the present invention is to combine the Ouye furnace's full-oxygen smelting with the tuyere coal injection technology of the blast furnace, and design a method of pulse injection of high-pressure oxygen in the hearth according to a certain sequence through the tuyere coal injection technology to deposit carbon in the hearth Accumulation cleanup.

In order to achieve the above object, the present invention provides the following basic solutions:

A method for cleaning furnaces by depositing carbon deposits in hearths, comprising the following steps:

S1: Adjust the pressure in the hearth;

S2: After inserting the pulse double spray gun into the furnace hearth, pulse injection of oxygen and nitrogen according to a certain pulse sequence;

S3: The pulse pressure of the pulse double spray gun is greater than the pressure in the furnace hearth, and when injecting oxygen and nitrogen, adjust the air pressure of the tuyere of the pulse double spray gun to keep the pressure at the top of the furnace the same.

The principle and effect of this basic scheme are as follows:

1. Compared with the existing technology, when the hearth is piled up due to long-term maintenance and opening of the furnace or other reasons, the pulse injection method is used to blow high-pressure pure oxygen into the tuyere to realize the loosening of the dead material column and the dead material column. The rapid combustion of internal carbon achieves the purpose of activating the center of the hearth.

2. Compared with the prior art, the air pressure at the tuyere and the pressure on the top of the furnace are kept stable during the pulse injection, and the process of continuous iron tapping and slag removal has obvious effects.

3. Compared with the existing technology, the adoption of this technology in the normal production process is beneficial to the improvement of the liquid permeability of the hearth, the improvement of the work efficiency of the hearth, and the effect of reducing the consumption of production and smelting.

4. Compared with the existing technology, through this technical research, the hearth accumulation caused by maintenance and raw fuel quality in the production process of blast furnace and Ouye furnace can be quickly reduced, and the problem of abnormal furnace condition and fuel ratio increase can be reduced. Technical solutions for emission reduction.

Further, in step S2, the pulse double spray gun includes a main pipe, a front conical ejection pipe and an auxiliary pipe, and one side of the furnace hearth has a tapered hole with the same shape as the front tapered ejection pipe. The front tapered ejection pipe is inserted into the taper hole, the secondary pipeline is arranged at the bottom of the main pipeline and the secondary pipeline communicates with the main pipeline, and the connection between the secondary pipeline and the main pipeline is provided with a control switch valve, and the main pipeline is used for Nitrogen is input, and the auxiliary pipeline is used for inputting oxygen.

Further, in step S1, the pressure in the furnace hearth is adjusted without stopping the furnace hearth. The pressure adjustment range is 1.0-2.0Mpa, the lowest pressure is 1.0Mpa, and the highest pressure is 2.0Mpa. When adjusting the pressure in the hearth, it is necessary to synchronize Adjust the temperature, the temperature adjustment range is 20°-30°.

Further, in step S2, the pulse sequence is that oxygen and nitrogen are alternately inserted into the furnace hearth, the beginning of the pulse sequence is nitrogen, and the nitrogen feeding time is 5-10min. After the nitrogen feeding time is satisfied, according to the oxygen passing time The pressure determines the oxygen blowing time, the oxygen blowing interval and the oxygen cycle period.

Further, before the step S2 is carried out, it is necessary to give priority to nitrogen gas for nitrogen hearth protection, and the nitrogen gas is filled with the hearth so that the nitrogen protection pressure is greater than the pulse pressure of the pulse double spray gun, and then the step S2 can be carried out according to a certain pulse sequence Do a pulse jet.

Further, in step S3, the pulse pressure of the pulse double spray gun is 3-4 times higher than the pressure in the furnace hearth.

Further, the tuyere line of the main pipeline in the pulse double spray gun and the tuyere line of the auxiliary pipeline in the pulse double spray gun need to be on the same straight line.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 shows a schematic structural view of the pulse double spray gun in a method for hearth carbon deposition and furnace cleaning proposed in the embodiment of the present application;

Fig. 2 shows a pulse sequence diagram of a method for cleaning a hearth with carbon deposits accumulated in an embodiment of the present application.

Implementation

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the specific implementation, structure, features and effects of the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments.

Embodiment as shown in Fig. 1 and Fig. 2:

From the background technology and actual production operation, it can be known that whether it is blast furnace smelting or Ouye furnace smelting, the hearth stacking method is limited, which seriously affects production and consumption. To realize furnace hearth carbon deposit accumulation cleaning, for this reason, a method for furnace hearth carbon deposition accumulation furnace cleaning is proposed.

A method for cleaning furnaces by depositing carbon deposits in hearths, comprising the following steps:

S1: Adjust the pressure in the hearth;

Specifically: whether the furnace hearth is a blast furnace or an Ouye furnace, in step S1, the pressure in the hearth is adjusted without stopping the hearth, and the pressure adjustment range is 1.0-2.0Mpa, the lowest pressure is 1.0Mpa, and the highest pressure is 2.0Mpa. When adjusting the pressure in the furnace hearth, the temperature needs to be adjusted synchronously, and the temperature adjustment range is 20°-30°. The purpose of prioritizing the pressure adjustment in the furnace hearth is to facilitate the implementation of step S2.

S2: After inserting the pulse double spray gun into the furnace hearth, pulse injection of oxygen and nitrogen according to a certain pulse sequence;

Specifically: as shown in Figure 1, the pulse double spray gun includes a main pipe, a front conical spray pipe and an auxiliary pipe. The outlet pipe is inserted into the taper hole, the auxiliary pipe is set at the bottom of the main pipe and the auxiliary pipe is connected with the main pipe, and a control switch valve is provided at the connection between the auxiliary pipe and the main pipe, the main pipe is used for nitrogen input, and the auxiliary pipe is used for input Oxygen, it should be noted that: In the structural design of the pulse double spray gun: the tuyere line of the main pipe in the pulse double spray gun and the tuyere line of the auxiliary pipe in the pulse double spray gun need to be on the same straight line; and, the pulse double spray gun inserts In the furnace hearth, it is necessary to strictly follow the sealing requirements to realize the sealing of the joint between the hearth and the pulse double spray gun; after the pulse double spray gun is installed, the overall pulse double spray gun should be kept stable and not shaken.

It should be noted that the inner diameter of the main pipe in the pulse double spray gun is 12-22mm, and the present embodiment selects an inner diameter of 18mm, and the inner diameter of the main pipe depends on the volume of the hearth. , the opposite is true.

Before step S2 is carried out, it is necessary to give priority to nitrogen gas for nitrogen furnace hearth protection, fill the furnace hearth with nitrogen gas so that the nitrogen protection pressure is greater than the pulse pressure of the pulse double spray gun, and then perform pulse injection according to a certain pulse sequence in step S2;

Regarding the pulse injection, the essence is the alternating injection of nitrogen and oxygen. Nitrogen and oxygen are realized by controlling the opening or closing of the switch valve. The injection of nitrogen is the signal "1", and the injection of oxygen is the signal "0". In this way, a pulse is formed. Regarding the pulse sequence of this embodiment, as shown in Figure 2, regarding the explanation of Figure 2, in step S2, the pulse sequence is that oxygen and nitrogen are alternately inserted into the furnace hearth, the beginning of the pulse sequence is nitrogen, and the nitrogen is passed through The injection time is 5-10min. After the nitrogen injection time is satisfied, the oxygen blowing time, oxygen blowing gap and oxygen cycle period are determined according to the pressure of oxygen; please refer to Figure 2, Figure 2 is the oxygen cycle time, when the oxygen cycle time After arriving, pass nitrogen, and the time of passing nitrogen is the same as the time of passing nitrogen at the beginning, which is 5-10min. If the initial time is 6 minutes, then the time for subsequent nitrogen injection is also 6 minutes, and the entire pulse time is 6 hours.

S3: The pulse pressure of the pulse double spray gun is greater than the pressure in the furnace hearth. When injecting oxygen and nitrogen, adjust the air pressure of the tuyere of the pulse double spray gun to keep the pressure at the top of the furnace the same. In this embodiment, in step S3, the pulse double spray gun The pulse pressure of the spray gun is 3-4 times higher than the pressure in the hearth.

The core of this method lies in: using pulse injection to blast high-pressure pure oxygen into the hearth to loosen the dead material column and quickly burn carbon inside the dead material column to avoid carbon deposits in the hearth and realize carbon combustion. Inject nitrogen to protect the furnace hearth to extrude the generated carbon dioxide, and then circulate pure oxygen again to clean up the carbon deposits in the furnace hearth.

Through this technical research, it is possible to quickly reduce the accumulation of hearths caused by maintenance and raw fuel quality in the production process of blast furnaces and Ouyeel furnaces, and the problems of abnormal furnace conditions and increased fuel ratios can be obtained, and a technical solution for reducing emissions can be obtained. Taking a 2500m³ blast furnace as an example, the general processing cycle for hearth accumulation is 5-15 days, and the coke ratio is increased to 500kg/t iron, resulting in high-silicon molten iron and increasing steelmaking costs. Blast furnace (during the hearth abnormal period, without calculating the loss of tuyere damage due to wind break) tapping iron is about 4000-4500t/d per day, resulting in an increase in fuel costs of about 2945 yuan/t*4000*(500-350)/1000=1.767 million Yuan/d, reducing processing time and saving 1.76 million yuan a day.

The purpose of the present invention is to combine the Ouye furnace's full-oxygen smelting with the tuyere coal injection technology of the blast furnace, and design a method of pulse injection of high-pressure oxygen in the hearth according to a certain sequence through the tuyere coal injection technology to deposit carbon in the hearth Accumulation cleanup.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art , without departing from the scope of the technical solution of the present invention, when the technical content disclosed above can be used to make some changes or be modified into equivalent embodiments with equivalent changes, but as long as it does not depart from the technical solution of the present invention, the technical content of the present invention In essence, any brief modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (7)

1. A method for cleaning a furnace by accumulating carbon deposited on a furnace hearth, which is characterized by comprising the following steps: the method comprises the following steps:

s1: adjusting the pressure in the hearth;

s2: after the pulse double spray gun is inserted into the hearth, oxygen and nitrogen are sprayed in a pulse mode according to a certain pulse sequence;

s3: when the pulse pressure of the pulse double spray gun is larger than the pressure in the hearth and oxygen and nitrogen are sprayed, the wind pressure of the wind opening of the pulse double spray gun is adjusted to be the same as the pressure of the furnace top.

2. The method for cleaning a furnace by accumulating carbon in a furnace hearth according to claim 1, wherein in the step S2, the pulse double spray gun comprises a main pipe, a front cone-shaped spray pipe and a secondary pipe, one side of the furnace hearth is provided with a cone hole with the same shape as the front cone-shaped spray pipe, the front cone-shaped spray pipe is inserted into the cone hole, the secondary pipe is arranged at the bottom of the main pipe and is communicated with the main pipe, a control switch valve is arranged at the joint of the secondary pipe and the main pipe, the main pipe is used for inputting nitrogen, and the secondary pipe is used for inputting oxygen.

3. The method according to claim 1, wherein in step S1, the pressure in the hearth is adjusted without stopping the hearth, the pressure is adjusted to 1.0-2.0Mpa, the lowest pressure is 1.0Mpa, the highest pressure is 2.0Mpa, and the temperature is adjusted to 20 ° -30 ° in synchronization with the adjustment of the pressure in the hearth.

4. The method for cleaning a furnace by accumulating carbon deposited on a furnace hearth according to claim 2, wherein in the step S2, oxygen and nitrogen are alternately inserted into the furnace hearth, the beginning of the pulse sequence is nitrogen, the nitrogen introducing time is 5-10min, and after the nitrogen introducing time is satisfied, the oxygen blowing time, the oxygen blowing gap and the oxygen circulation period are determined according to the pressure passing through the oxygen.

5. The method for cleaning a furnace by accumulating carbon deposited on a furnace hearth according to claim 4, wherein before the step S2 is performed, nitrogen is preferably introduced to perform nitrogen furnace hearth protection, the furnace hearth is fully filled with nitrogen, and pulse spraying according to a certain pulse sequence in the step S2 can be performed after the nitrogen protection pressure is higher than the pulse pressure of the pulse double spray gun.

6. A method of hearth soot accumulation cleaning as in claim 1 wherein in step S3 the pulse pressure of the pulse double lance is 3-4 times greater than the pressure in the hearth.

7. A method of hearth soot accumulation furnace cleaning as in claim 2 wherein the tuyere line of the main pipe in the pulse duplex lance is required to be collinear with the tuyere line of the secondary pipe in the pulse duplex lance.

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