Design of Blast Furnace Hot Blast Stove System
The blast furnace hot blast stove system also known as hot blast circulation system is an important part of a modern blast furnace system. The hot air circulation system mainly consists of a hot-blast stove, a blower, a ducting system, a cooling and purifying system and a hot air control system. The main purpose of this system is to heat the cold, fresh air to the blast furnace temperature, usually 1430-1560 ˚C, and to distribute the hot air to the furnace in a suitable way. The design of the blast furnace hot blast stove system includes the selection of a hot-blast stove, the design of the blower, the determination of a routing strategy for the hot air in the furnace, the ventilation system, the smoke dust removal and purification system, the cooling and circulation system, and the temperature control system.
1. Selection of hot-blast stove
The selection of hot-blast stove is the first step in the design of the blast furnace hot blast stove system. The hot-blast stove should be able to withstand the working condition of the blast furnace and its cooling level, as well as its energy efficiency, steel usage and other factors. Generally, there are two types of hot-blast stoves, indirect hot-blast stoves and direct hot-blast stoves. The indirect hot-blast stove has the advantages of a lower energy consumption and higher efficiency, but it generally requires more steel usage and the construction is more complicated. The direct hot-blast stove has the advantages of a lower steel consumption and simpler construction, but it has a lower energy efficiency and higher energy consumption.
2. Design of Blower
The blower is used to feed air into the hot blast stove and to provide heated air to the blast furnace. The pressure generated by the blower must be higher than the pressure at the top of the hot-blast stove, otherwise the heated air will not be delivered into the furnace. The power rating of the blower should also be higher than the thermal power of the hot-blast stove. The blower also has to be designed according to the shape of the burning chamber of the hot-blast stove, as well as the diameter of the hot blast pipe, the size of the different sections of the blast furnace, and the cooling arrangement.
3. Determination of Route Strategy for Hot Air in Furnace
The route strategy for the hot air in the blast furnace is the determination of the temperature of the hot air in each section of the blast furnace, the temperature of the hot air when entering the furnace and the temperature of the hot air when leaving the furnace. Generally, the hot air should enter the blast furnace from the upper section first, as the top of the furnace has the highest temperature. The hot air should then gradually decrease its temperature as it moves down the furnace, according to the blast furnace temperature at each section.
4. Ventilation System
The ventilation system is used to exhaust the used air from the furnace and to maintain the correct air pressure in the furnace. In order to ensure proper ventilation, the air inlet and exhaust should be designed in such a way that they create an adequate air pressure in each section of the furnace. The size of the ventilation system should also be large enough to handle the airflow needed at each section.
5. Smoke Dust Removal and Purification System
The smoke dust removal and purification system is used to reduce the dust and smoke content in the air that is exhausted from the furnace. The purification system usually consists of dust collectors, cyclones and other equipment to separate the dust particles and to reduce the smoke content in the exhaust gas.
6. Cooling and Circulation System
The cooling and circulation system is used to reduce the heat taken by the hot air from the hot-blast stove, and to distribute the cooled air to the blast furnace in an appropriate way. Generally, two types of cooling systems are used, the forced cooling system, which uses a fan to achieve a higher cooling rate and a lower temperature, and the indirect cooling system, which uses water cooling pipes to achieve a lower temperature drop.
7. Temperature Control System
The temperature control system is used to regulate the temperature in the furnace and to maintain a stable furnace temperature. The temperature control system usually consists of temperature sensors, regulators, and other instruments and devices to detect the temperature conditions in different sections of the furnace and to adjust the temperature accordingly.
In conclusion, the design of the blast furnace hot blast stove system is very important and it involves various considerations, such as the selection of hot-blast stove, the design of the blower, the routing strategy of the hot air in the furnace, the ventilation system, the smoke dust removal and purification system, the cooling and circulation system, and the temperature control system. The correct design of these elements will help to ensure the efficient and safe operation of the blast furnace.
