Research Paper
The following research paper was written by the notebook team of MACHingjay Mining Enterprises
Innovations in Clean Coal Technology
Coal has been a major energy source in the United States since the early 1800’s (“History of Coal Use”). Since it is far less expensive to mine and is more abundant than other energy sources, coal has been in high demand and widely used for many purposes including generating electricity, powering steam engines, and producing liquid fuel. However, coal mining can be a dangerous job, and burning coal gives off dangers emissions which is harmful to the environment and can be dangerous to human health. Two innovations in clean coal technology that address the emission problems are the flue gas desulfurization system or “scrubber” and gasification.
When power companies burn coal to generate electricity, there is a discharge given off that contains toxic gasses which are harmful for humans to breathe. Sulfur dioxide is one of the chemicals released, and its “particles [can] penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease, such as emphysema and bronchitis.” (“Sulfur Dioxide”). An innovative solution to this problem is the flue gas desulfurization system or “scrubber”, which removes 99% to 99.9% of the sulfur dioxide from the emissions.
Scrubbers basically act as giant washing machines. As seen in the following diagram, the sulfur dioxide (SO2) is forced through a flue, and then it is sprayed with a mixture of water and calcium oxide (CaO), also known as lime. The lime neutralizes the sulfur dioxide and the resulting emission is water vapor (Harris, 2).
Source: Principles of General Chemistry
This process produces a sludge by-product that can be transformed into gypsum, which can be used as wallboard or other building materials as well as agricultural products (“Scrubber”).
Scrubbers are being used in several electricity generating plants in the southeast region including: Plant Victory Daniel, Moss Point Mississippi (“Scrubber”); James M. Barry Generating Plant, Bucks, Alabama; James H. Miller, Jr. Generating Plant, Quinton, Alabama (“Generating Plants”) and James F. Crist Generating Plant, Pensacola, Florida (“Plant Crist”).
Gasification is another way that coal energy is being made better for the environment. Coal gasification is the process of chemically transforming the coal into synthesis gas or “syngas” (“Kemper Project”). This method removes harmful emissions because the coal is chemically broken down rather than burned by means of combustion. This method of chemical transformation is much cleaner for the environment, but it still provides a reliable energy source using coal.
Traditional coal-fired power plants burn coal in a boiler using combustion (Harris, 2). A power plant that incorporates gasification use gasifiers instead of boilers, as seen in the following diagram.
The coal is exposed to extremely high heat and pressure in the gasifier. Gasifiers operate at about 2,600°F (1,427°C) and about 1,000 pounds per square inch, which is much hotter than a coal boiler (Harris, 2). When the coal undergoes exposure to the heat and pressure, the coal molecules break apart. The gases that are released are carbon monoxide and hydrogen which combine to make syngas. Syngas can be used to generate electricity or turned into liquid fuel (“Gasification”).
Kemper County Energy Facility in Kemper County, Mississippi, is currently utilizing an integrated gasification combined cycle (IGCC) design called TRIG™ technology. TRIG™, or Transformed Integrated Gasification, was developed over the last two decades at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama (“IGCC”). Not only does this process turn coal into syngas, but it also “sends lignite not converted to gas in the initial process back for a second round of gasification” which makes for less waste (“TRIG”).
While coal may be one of earth’s finite resources, “coal produces more than 40 percent of the world’s electricity…and that percentage is going up. Since 1973, coal added more to the global energy supply than any other source” (Mann). New technologies are making coal cleaner and safer for the environment.