- Home
- Industry News
- Industry News
Hot Blast Furnace for Ironmaking Blast Furnace
Hot blast furnace is a thermodynamic machine, which has been widely used in my country since the end of the 1970s. It has become a replacement product of electric heat source and traditional steam-powered heat source in many industries. There are many varieties and complete series of hot blast stoves. They are divided into hand-burning and machine-burning by the way of adding coal. They are divided into coal, oil and gas stoves by the type of fuel.
The function of the iron-making blast furnace hot blast furnace is to heat the blast to the required temperature to improve the benefit and efficiency of the blast furnace; it works according to the principle of "heat storage". The gas is burned in the combustion chamber, and the high-temperature exhaust gas passes through the checker bricks to store heat. When the checker bricks are fully heated, the hot blast stove can be changed to air supply. At this time, the relevant combustion valves are closed, the air supply valves are opened, and the cold air passes through Checker bricks are heated and sent out. When the blast furnace is equipped with 3-4 hot blast stoves, two or three are heated, one is for air supply, and when the blast furnace is replaced in turn, two are heated.Main refractory materials used in hot blast stoves
Due to the extreme temperature difference between the upper and lower temperature of the hot blast furnace, the refractory materials used in each section vary greatly.
Vault area of hot blast furnace. The vault is the space connecting the combustion chamber and the regenerator, including the working layer brick, the filler layer and the thermal insulation layer. It is necessary to maintain the structural stability of the vault at high temperatures during work, and at the same time, it is necessary to evenly distribute the high-temperature flue gas into the regenerator during combustion. Therefore, the vault is designed to be spherical in the design to avoid the side of the furnace shell. The thrust in the direction is unstable. Because the temperature of the vault area of the hot blast stove is very high, exceeding 1400℃, the products used in the working layer are mostly silica bricks, mullite bricks, sillimanite, andalusite bricks or low creep high alumina bricks; the exterior of the working layer The masonry is diatomaceous earth bricks or thermal insulation clay bricks; the outermost layer is filled with water slag or water slag diatomaceous earth filler
Great wall. The large wall of the hot blast stove refers to the wall part of the hot blast stove body, including the working layer brick, the filling material layer and the thermal insulation layer. The working layer bricks choose different refractory bricks according to the upper and lower temperatures, and the thickness is between 300 and 500 mm. Because the upper part has the highest temperature, silica bricks, mullite bricks, etc. are mostly used. High alumina bricks, sillimanite bricks and clay bricks can be used in the middle and lower parts. A layer of diatomite insulation layer is built between the large wall and the furnace shell, and a layer of dry water slag filler is filled between the insulation layer and the large wall to have the effect of heat preservation. Due to the high temperature in the high-temperature zone of the large wall, in order to keep warm, a layer of light clay bricks is often built outside the working layer bricks in the high-temperature zone, and an insulating filler layer is filled between the two insulation layers.
Regenerator. The regenerator is a space filled with checkered bricks, and its main function is to use the checkered bricks inside to exchange heat with high-temperature flue gas and combustion-supporting air. Therefore, checker bricks as heat storage and heat transfer medium should have a larger heating area, higher thermal conductivity and quality to facilitate heat exchange and heat storage; the method of increasing the heating area is mainly in the unit area As the number of holes of checker bricks increases, the number of holes of checker bricks in the regenerator tends to increase. In order to improve the thermal conductivity of the material, black silica bricks are commonly used in the checker bricks inside the regenerator in Europe, because the black silica bricks contain high iron oxide content, high density, high thermal conductivity, and strong heat storage capacity. High exchange efficiency. Therefore, the upper part of the regenerator adopts siliceous checker bricks, the middle part of the regenerator adopts low-creep high-alumina bricks, mullite bricks, sillimanite, andalusite bricks, etc., and the lower part of the regenerator generally adopts clay bricks.
Combustion chamber. The combustion chamber is the space where the gas burns. The setting of the combustion chamber space has a great relationship with the furnace type and structure of the hot blast stove. The combustion chamber of the external combustion hot blast stove and the regenerator are arranged separately, while the combustion chamber and the regenerator of the internal combustion hot blast stove are arranged in a large wall, separated by a partition wall in the middle, and the combustion chamber of the top combustion hot blast stove is arranged in Silica bricks, mullite bricks or low creep high alumina bricks are used in the high temperature area of the combustion chamber of the regenerator, and high alumina bricks and clay bricks are used in the medium and low temperature areas.
Partition wall. The partition wall is a furnace wall that separates the combustion chamber and the regenerator set in the internal combustion hot blast stove. The partition wall of the hot blast stove is a furnace wall heated on both sides, while the large wall is heated on one side. Therefore, the internal combustion type hot blast stove has a large expansion of the furnace wall, which will cause the partition wall to collapse to the checker brick side; in addition, the partition wall The temperature difference between the two sides of the lower part is large, and the difference in thermal expansion is large. The partition wall will bend and crack during operation, causing the grate and pillars at the bottom to burn out. Therefore, expansion joints and reinforcement methods should be reserved during masonry. The refractory material used in the partition wall is the same as the refractory material used in the combustion chamber.
Burner. The hot blast stove burner is a device that mixes gas and air and sends them to the combustion. The burners used in hot blast stoves are divided into two types: metal and ceramic. The ceramic burners are mainly mullite or cordierite-mullite.
want to know more refractory material,welcome to contact us
