Karma Snack News Stream

To some, the term “clean coal” doesn’t make sense because it burns so dirty. The technology being developed is addressing the negative aspects of coal use. There are those that are opposed to any coal use because they feel it has a negative impact on the environment. There are some that want to wait for wind and/or solar technology to become more available. The problem with waiting is that nearly half the electricity produced in the US is already being produced by the use of coal. Clean coal technology cannot and will not wait. Diversity in energy sources is essential and clean coal is part of the diversity so there isn’t dependency on limited energy options. When coal is burned, it releases carbon dioxide in the air. This can contribute to global warming, acid rain, health risks, and pollution of the environment. From a distance, it may look appealing to eliminate coal use. That is unlikely to happen not only because it is already so widely used, but also because it is inexpensive and plentiful. Further development is expected to make coal more environmentally friendly. Coal is a fossil fuel made up of mostly carbons and hydrocarbons. Plastics, tar, and fertilizers are all made from ingredients of coal. A solidified carbon called coke is a coal derivative, and it melts iron ore and reduces it to create steel. This makes up for a small percentage of how the U.S. coal supply is used. Approximately 92 percent of coal goes to producing power. The steam that turns turbines and generates electricity for the electric companies and businesses that have power plants is created from burning coal. The flue gas that is released from burning coal emits carbon dioxide, sulfur dioxide, and other harmful emissions. The technologies that are used to prevent this from happening and to reduce the amount of harmful emissions into the atmosphere include the following: COAL WASHING This cleans (purifies) the coal before it burns. Coal washing removes the unwanted minerals by mixing coal that is crushed with a liquid so that the impurities and unwanted minerals can separate and settle. WET SCRUBBERS (FLUE GAS DESULFURIZATION SYSTEMS) Sulfur dioxide, nitrogen, oxides, and particulates are minimized with wet scrubbing. Acid rain is caused in large part by sulfur dioxide. Synthetic gypsum (a component of drywall) is created when flue gas is sprayed by limestone and water. LOW-NOx (NITROGEN OXIDE) BURNERS Nitrogen oxides cause ground-level ozone. Low-NOx burners reduce the creation of nitrogen oxides because it manipulates the combustion process and it restricts oxygen. ELECTROSTATIC PRECIPITATORS Particulates that aggravate asthma and can cause respiratory problems. Electrostatic precipitators prevent particulates from entering the air by capturing them on collection plates by charging the particles with an electrical field. GASIFICATION Burning isn’t the only option for releasing coal’s energy. Integrated Gasification Combined Cycle (IGCC) systems don’t burn coal, but uses steam and hot pressurized air or oxygen combine with coal. It forces carbon molecules apart and the resulting syngas (mixture of carbon monoxide and hydrogen), is then cleaned and burned in a gas turbine to make electricity. The heat energy from the gas turbine also powers a steam turbine. So IGCC power plants have the potential to reach a fuel efficiency of 50 percent because they create two forms of energy. CARBON CAPTURE The clean coal options of carbon capture is probably the one most people have heard of. It holds the most promise when it comes to clean coal technology. It works by catching and seizing carbon dioxide (CO2) emissions from power plants. Reducing CO2 that is released into the atmosphere has become a major international concern due to carbon dioxide contributing to global warming. FLU-GAS SEPARATION CO2 is removed with a solvent, and then the CO2 is stripped with steam. The steam is condensed into a concentrated stream. The gas can be used commercially and offset some of the costs. OXY-FUEL COMBUSTION To sidestep the energy-intensive process of separating the carbon dioxide from other flue gasses, oxy-fuel combustion burns the fuel in enriched or pure oxygen. The flue gas that is produced is mostly water and CO2. PRE-COMBUSTION CAPTURE This technology removes the carbon dioxide before it is burned as part of a gasification process. There is still more work to be done to continue reducing the environmental risks of burning coal. All forms of CO2 storage will require careful preparation and monitoring to prevent environmental problems that outweigh the benefits of carbon dioxide containment. It is an attainable goal and necessary for a healthy energy future for America.