Coal is the United States’ most plentiful fossil fuel, but traditional methods of burning coal produce emissions that can reduce air and water quality. Using coal can help the United States achieve domestic energy security if we can develop methods to use coal that won’t damage the environment.
The Clean Coal Technology Program is a government and industry funded program that was begun in 1986 in an effort to resolve U.S. and Canadian concern over acid rain. Clean coal technologies remove sulfur and nitrogen oxides before, during, and after coal is burned, or convert coal to a gas or liquid fuel. Clean coal technologies are also more efficient, using less coal to produce the same amount of electricity.
Fluidized Bed Combustor: One technique that cleans coal as it burns is a fluidized bed combustor. In this combustor, crushed coal is mixed with limestone and suspended on jets of air inside a boiler. The coal mixture floats in the boiler much like a boiling liquid. The limestone acts like a sponge by capturing 90 percent of the organic sulfur that is released when the coal is burned. The bubbling motion of the coal also enhances the burning process.
Combustion temperatures can be held to 1,500 degrees Fahrenheit, about half that of a conventional boiler. Since this temperature is below the threshold where nitrogen pollutants form, a fluidized bed combustor keeps both sulfur and nitrogen oxides in check.
Coal Gasification: Another clean coal technology bypasses the conventional coal burning process altogether by converting coal into a gas. This method removes sulfur, nitrogen compounds, and particulates before the fuel is burned, making it as clean as natural gas.
Carbon Capture and Storage: Research and demonstration projects are underway around the U.S. and world to capture carbon dioxide from power plants and store it deep underground in geologic formations. Researchers are investigating the best ways to capture carbon dioxide, either before or after coal is combusted. The carbon dioxide will then be compressed converting the gas to a liquid. It will then be transported via pipeline to appropriate storage sites. Three different types of locations have been identified as being able to hold carbon dioxide :
1) deep saline formations,
2) oil and gas reservoirs that are near depletion or have been depleted
3) unmineable coal seams.
The Clean Coal Technology Program is a government and industry funded program that was begun in 1986 in an effort to resolve U.S. and Canadian concern over acid rain. Clean coal technologies remove sulfur and nitrogen oxides before, during, and after coal is burned, or convert coal to a gas or liquid fuel. Clean coal technologies are also more efficient, using less coal to produce the same amount of electricity.
Fluidized Bed Combustor: One technique that cleans coal as it burns is a fluidized bed combustor. In this combustor, crushed coal is mixed with limestone and suspended on jets of air inside a boiler. The coal mixture floats in the boiler much like a boiling liquid. The limestone acts like a sponge by capturing 90 percent of the organic sulfur that is released when the coal is burned. The bubbling motion of the coal also enhances the burning process.
Combustion temperatures can be held to 1,500 degrees Fahrenheit, about half that of a conventional boiler. Since this temperature is below the threshold where nitrogen pollutants form, a fluidized bed combustor keeps both sulfur and nitrogen oxides in check.
Coal Gasification: Another clean coal technology bypasses the conventional coal burning process altogether by converting coal into a gas. This method removes sulfur, nitrogen compounds, and particulates before the fuel is burned, making it as clean as natural gas.
Carbon Capture and Storage: Research and demonstration projects are underway around the U.S. and world to capture carbon dioxide from power plants and store it deep underground in geologic formations. Researchers are investigating the best ways to capture carbon dioxide, either before or after coal is combusted. The carbon dioxide will then be compressed converting the gas to a liquid. It will then be transported via pipeline to appropriate storage sites. Three different types of locations have been identified as being able to hold carbon dioxide :
1) deep saline formations,
2) oil and gas reservoirs that are near depletion or have been depleted
3) unmineable coal seams.