Flue gas from blast furnace
Flue gas is a type of gases emitted from different sources like industrial activity, burning of fuels, etc. It is a complicated mixture of different gases and air pollutants, mainly carbon dioxide, nitrogen oxides and water vapor along with other components such as sulfur dioxide, particulate matter and volatile organic compounds. Blast furnace flue gas is one such type of flue gas composed mainly of carbon dioxide, nitrogen oxides and water vapor.
The blast furnace process is used in the steel industry to produce molten iron from ore. In the process, oxygen, coke, and limestone are charged into a blast furnace where they are heated to very high temperatures. This heating process causes the coke to burn, releasing large amounts of carbon dioxide, heat and the impurities present in the ore melt into the liquid iron. The impurities are then removed or burned out with the forming of slag, which is a nonmetallic material. The off-gases generated by this combustion process are hot and contain large amounts of particulate matter and toxic chemicals such as nitrogen oxides, sulfur oxides and volatile organic compounds. These hot gases are then passed through a series of scrubbers, electrostatic precipitators, fabric filters, and other air pollution control devices, to remove the particulate matter, toxic chemicals, and other air pollutants from the flue gas stream.
The main components of blast furnace flue gas are normally composed of carbon dioxide (up to about 90%), nitrogen oxides (up to about 5%), and water vapor (up to about 10%). Small amounts of other components such as carbon monoxide, sulfur dioxide, and hydrocarbons can also be present. Due to the presence of these components, the flue gas has a very high temperature and its composition can vary greatly depending upon the feed materials, operating temperature and air flow rate.
The composition of blast furnace flue gas is usually determined by gas analyzers. The effective control of blast furnace emissions is essential to reduce levels of air pollutants and protect the environment. Various technologies are used for the control of emissions from the blast furnace process. These include using pollutant control devices such as scrubbers, baghouses and electrostatic precipitators to reduce the levels of particulate matter, toxic chemicals, and other air pollutants.
Using pollution control devices is only part of the solution. Proper operating and maintenance of the blast furnace is essential to reduce the levels of air pollutants. Proper operating practices such as proper charging and firing of the furnace, controlling the oxygen supply to the furnace, ensuring good combustion conditions, and proper monitoring of the furnace process all help reduce the levels of air pollutants.
The control of blast furnace emissions can also be accomplished by use of materials and processes that reduce or eliminate the release of pollutants. These include the use of low-sulfur coke, which reduces the emission of sulfur oxides, and the use of limestone or lime to reduce the emission of nitrogen oxides.
The control of blast furnace emission can also be achieved by controlling the operating temperature and the air flow rate in the furnace. By controlling these two parameters, the amount of pollutants released can be reduced. The proper design and operation of the blast furnace can also minimize the release of air pollutants.
In conclusion, we can say that proper control of blast furnace emissions is essential in order to reduce the levels of air pollutants and protect the environment. Various technologies and practices can be used for the control of emissions from the blast furnace process.
