Burning of coal results in the emission of many toxic pollutants, and is the source of half of the total air pollutants released in the world. The main pollutants emitted by coal burning are carbon dioxide (CO2), sulfur dioxide (SO2), particles, nitrogen oxides (NOx) and certain heavy metals. These pollutants can cause respiratory problems, acid rain and global warming.
Secondary burning is a process that involves burning coal a second time to reduce the level of airborne pollutants released into the atmosphere. This process is used to reduce the amount of pollutant released with the original coal burning. During the secondary burning process, carbon dioxide, nitrogen oxides and sulfur dioxide are exposed to high temperature, resulting in chemical reactions that convert them into less hazardous compounds.
Secondary burning involves using a combustion chamber that is heated to temperatures reaching 1000 to 1600 degrees Celsius. The high-temperature environment causes the sulfur dioxide and nitrogen oxides in the coal gas to react with other chemicals and change into less toxic compounds that can be safely released into the atmosphere. Carbon dioxide is converted into carbon monoxide (CO) and other non-toxic compounds by the process of oxidation.
The secondary burning process also reduces the size of the coal particles, which is beneficial in terms of health. This process also eliminates some of the pollutants found along with the coal such as mercury, arsenic and other heavy metals. These pollutants are very toxic, and can accumulate in the human body and cause health and environmental issues.
Secondary burning is a useful process which can help reduce the amount of air pollution, due to the burning of coal. It helps to reduce the health issues associated with the burning of coal, and is more cost effective than other processes such as scrubbing, which require additional chemicals and energy to be used. However, it must be remembered that the process does not eliminate all pollutants, and also does not reduce the levels of carbon dioxide emissions. There are also issues associated with the burning process itself, such as smoke, smell and visual pollution, which can be a nuisance to those living near the burning process.
