What are the advantages and disadvantages of top fired hot blast stoves? Please tell me

There are many varieties and series of hot blast stoves, which are divided into two kinds of hand burning and machine burning by coal, coal, oil and gas furnaces by fuel types, high-temperature furnaces and medium-temperature furnaces by output air temperature, indirect and direct types in the form of conveying, combined and separated types in the form of heat exchangers, and coal grinding and powder sprayers are equipped on large furnaces. There is no standard for specific specifications and models, and the following standardized marks are made for the time being: JDC-MF stands for direct-fired pulverized coal-fired hot blast stove.

JDC-Y stands for Direct Fired Fuel Hot Blast Stove. JDC-Q stands for Direct Fired Gas Hot Blast Stove. JDC-M stands for Indirect Coal-fired Hot Blast Stove.

JDC-Y stands for Indirect Oil-fired Hot Blast Stove. JDC-Q stands for Indirect Gas Hot Blast Stove, RH-M stands for Split Coal-fired Hot Blast Stove, and RH-Y stands for Split Oil-fired Hot Blast Stove. RH-Q stands for Split Gas Hot Blast Stove.

BHL-H stands for Recuperative Type....

The so-called top-fired hot blast stove.

It refers to the burner installed on the top of the hot blast furnace of ironmaking equipment, burning in the vault space, without the need for a special combustion chamber, also known as the non-combustion chamber hot blast stove.

In order to ensure that the gas and air are well mixed and completely burned in a short period of time, a short flame or flameless burner with large combustion capacity is used, and a semi-jet short flame burner is commonly used.

Due to the high hot air outlet of the top fired hot blast furnace, the installation plane of the hot air main pipe is required to be high, and the strength of the pillar structure is high, so the plane layout of the hot blast furnace is used in a rectangular combination. Because the burner and hot blast valve are located on the top platform, the operation, maintenance and installation of the top fired hot blast furnace require mechanization and automation. In addition, because these water-cooled valves are installed at a high elevation, the water supply pressure of the cooling water is required to be correspondingly increased for the use of large top-fired hot blast stoves, and the key to this is the design of high-power and high-efficiency short-flame burners.

The top-fired hot blast furnace absorbs the advantages of internal combustion and external combustion hot blast furnace and overcomes some of their shortcomings, its structure can adapt to the requirements of modern blast furnace to high temperature, high pressure and large-scale development, and the combustion capacity successfully reduces many equipment while meeting the production requirements, which is convenient for production operation and management. Therefore, it represents the development direction of a new generation of high air temperature hot blast stoves.

In the hot blast furnace, the high-temperature flame and combustion products generated by fuel combustion directly wash the refractory masonry of the furnace wall and vault, the dust in the gas reacts with the refractory material, and the lattice brick and furnace wall are deformed by the long-term action of planting load, which will cause damage to the masonry.

The masonry is subjected to high temperature, the inner surface temperature is high, the outer surface temperature is low, the internal expansion is large, and the external expansion is small, so the masonry is subjected to compressive stress inside and tensile stress externally. The inner surface of the brick is easily crushed locally, resulting in thermal spalling of the brick surface and cracking of the brick joints, causing the brick arch or vault brick to sink. The dust in the combustion products reacts chemically with the bricks, forming a low-melting compound, which melts at high temperatures, which is another reason for the spalling of the vault brickwork.

On large hot blast stoves, this spalling phenomenon is more serious, especially when the temperature is too high due to improper operation.

On the lower horizontal plane of lattice brick or furnace wall masonry, the masonry is subjected to a large self-compression and planting load, coupled with the action of repeated fluctuations in temperature, the masonry is prone to cracks and deformation.

The highest surface temperature of refractory bricks is used as the working temperature for hot blast furnace masonry, and this is used as the standard for selecting refractory bricks. The high-temperature parts of the hot blast furnace, including the vault, the upper part of the combustion chamber, the lattice bricks and the furnace wall of the upper part of the regenerator, are based on the temperature of the vault, so the refractory and creep of the refractory material should be higher than the temperature of the vault. In these parts, silica bricks or high-quality high-alumina bricks are mostly used.

Excerpt from: Metallurgy.

1) Wide adaptability of coal types;

2) High combustion efficiency, thermal efficiency of 95%, and fuel consumption of equal heat supply are shown in the table

3) The output Biqiaona heat load is stable, mechanical combustion, simple operation, and very convenient adjustment;

4) Environmental protection standards, no secondary pollution, clean operating environment;

5) The hot air has high cleanliness, and the dust content is 30 120mg nm3;

6) Hot air temperature adjustment is convenient for dissipation, adjustable below 1000, and continuous hot air temperature stability 5;

7) The equipment has strong durability, low cost and simple maintenance.

The top-fired hot blast stove is a device for heating blast furnace blast blast furnace, which is an indispensable and important part of modern blast furnace.