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Class F Fly Ash
Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs), are categorized in four groups, each based on physical and chemical forms derived from coal combustion methods and emission controls: *Fly ash is captured after coal combustion by filters ( bag houses), electrostatic precipitators and other air pollution control devices. It comprises 60 percent of all coal combustion waste (labeled here as coal combustion products).It is most commonly used as a high-performance substitute for Portland cement or as clinker for Portland cement production. Cements blended with fly ash are becoming more common. Building material applications range from grouts and masonry products to cellular concrete and roofing tiles. Many asphaltic concrete pavements contain fly ash. Geotechnical applications include soil stabilization, road base, structural fill, embankments and mine reclamation. Fly ash also serves as filler in wood and plastic products, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous ( Pennsylvanian) and Permian times. Many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity. Some iron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While the activation energy must be overcome to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. Combustion is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood and coal, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fly Ash
Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK) plurale tantum: coal combustion residuals (CCRs)is a coal combustion product that is composed of the particulates (fine particles of burned fuel) that are driven out of coal-fired boilers together with the flue gases. Ash that falls to the bottom of the boiler's combustion chamber (commonly called a firebox) is called bottom ash. In modern coal-fired power plants, fly ash is generally captured by electrostatic precipitators or other particle filtration equipment before the flue gases reach the chimneys. Together with bottom ash removed from the bottom of the boiler, it is known as coal ash. Depending upon the source and composition of the coal being burned, the components of fly ash vary considerably, but all fly ash includes substantial amounts of silicon dioxide (SiO2) (both amorphous and crystalline), aluminium oxide (Al2O3) and calcium oxide (CaO), the main mineral compounds in coal-bearing rock strata. The u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dust Collector
A dust collector is a system used to enhance the quality of air released from industrial and commercial processes by collecting dust and other impurities from air or gas. Designed to handle high-volume dust loads, a dust collector system consists of a blower, dust filter, a filter-cleaning system, and a dust receptacle or dust removal system. It is distinguished from air purifiers, which use disposable filters to remove dust. History The father of the dust collector was Wilhelm Beth from Lübeck. In 1921, he patented three filter designs that he had pioneered to remove dust from air. Uses Dust collectors are used in many processes to either recover valuable granular solid or powder from process streams, or to remove granular solid pollutants from exhaust gases prior to venting to the atmosphere. Dust collection is an online process for collecting any process-generated dust from the source point on a continuous basis. Dust collectors may be of single unit construction, or a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portland Cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2 to 3 percent of gypsum. Several types of portland cement are available. The most common, called ordinary portland cement (OPC), is grey, but white Portland cement is also available. Its name is derived from its resemblance to Portland stone which was quarried on the Isle of Portland in Dorset, England. It was named by Joseph Aspdin who obtained a patent for it in 1824. His son William Aspdin is regarded as the inventor of "modern" portland cement due to his developments in the 1840s. The low cost and widespread availability of the limestone, shales ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flue-gas Desulfurization
Flue-gas desulfurization (FGD) is a set of technologies used to remove sulfur dioxide () from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration. Methods Since stringent environmental regulations limiting emissions have been enacted in many countries, is being removed from flue gases by a variety of methods. Common methods used: * Wet scrubbing using a slurry of alkaline sorbent, usually limestone or lime, or seawater to scrub gases; * Spray-dry scrubbing using similar sorbent slurries; *Wet sulfuric acid process recovering sulfur in the form of commercial quality sulfuric acid; * SNOX Flue gas desulfurization removes sulfur dioxide, nitrogen oxides and particulates from flue gases; *Dry sorbent injection systems that introduce powdered hydrated lime (or other sorbent material) into exhaust ducts to eliminate and from process emissions. For a typical coal-fired power station, flue-ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flue Gas
Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler or steam generator. Quite often, the flue gas refers to the combustion exhaust gas produced at power plants. Its composition depends on what is being burned, but it will usually consist of mostly nitrogen (typically more than two-thirds) derived from the combustion of air, carbon dioxide (), and water vapor as well as excess oxygen (also derived from the combustion air). It further contains a small percentage of a number of pollutants, such as particulate matter (like soot), carbon monoxide, nitrogen oxides, and sulfur oxides. Most fossil fuels are combusted with ambient air (as differentiated from combustion with pure oxygen). Since ambient air contains about 79 volume percent gaseous nitrogen (N2), which is essentially non-combustible, the largest part of the flue gas from most fossil-fuel combustion is uncombusted nitrogen. Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottom Ash
Bottom ash is part of the non-combustible residue of combustion in a power plant, boiler, furnace or incinerator. In an industrial context, it has traditionally referred to coal combustion and comprises traces of combustibles embedded in forming clinkers and sticking to hot side walls of a coal-burning furnace during its operation. The portion of the ash that escapes up the chimney or stack is, however, referred to as '' fly ash''. The clinkers fall by themselves into the bottom hopper of a coal-burning furnace and are cooled. The above portion of the ash is also referred to as bottom ash. Most bottom ash generated at U.S. power plants is stored in ash ponds, which can cause serious environmental damage if they experience structural failures. Ash handling processes In a conventional water impounded hopper (WIH) system, the clinker lumps get crushed to small sizes by clinker grinders mounted under water and fall down into a trough from where a water ejector takes them out to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ash Pond
An ash pond, also called a coal ash basin or surface impoundment,U.S. Environmental Protection Agency (EPA), Washington, D.C. "Hazardous and Solid Waste Management System; Identification and Listing of Special Wastes; Disposal of Coal Combustion Residuals from Electric Utilities." Proposed rule. ''Federal Register,'' , June 21, 2010. is an engineered structure used at coal-fired power stations for the disposal of two types of coal combustion products: bottom ash and fly ash. The pond is used as a landfill to prevent the release of ash into the atmosphere. Although the use of ash ponds in combination with air pollution controls (such as wet scrubbers) decreases the amount of airborne pollutants, the structures pose serious health risks for the surrounding environment. Ash ponds use gravity to settle out large particulates (measured as total suspended solids) from power plant wastewater. This technology does not treat dissolved pollutants. The ponds generally have not been built as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Pollution
Groundwater pollution (also called groundwater contamination) occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution (or contamination) can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease (water-borne diseases). The pollutant often creates a contaminant plume within an aquifer. Movement of water and dispersion within the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2014 Dan River Coal Ash Spill
In February 2014, an Eden, North Carolina facility owned by Duke Energy spilled 39,000 tons of coal ash into the Dan River. The company later pled guilty to criminal negligence in their handling of coal ash at Eden and elsewhere and paid extremely minimal fines of over $5 million, compared to its $24 billion revenue in 2014. The U.S. Environmental Protection Agency (EPA) has since been responsible for overseeing cleanup of the waste. EPA and Duke Energy signed an administrative order for the site cleanup. Incident On February 2, 2014 a drainage pipe burst at a coal ash containment pond owned by Duke Energy in Eden, North Carolina, sending 39,000 tons of coal ash into the Dan River. In addition to the coal ash, 27 million gallons of wastewater from the plant was released into the river. The broken pipe was left unsealed for almost a week before the draining coal ash was stopped. The ash was deposited up to from the site of the spill and contained harmful metals and chemicals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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