Coal analyzer
Encyclopedia
Coal analyzers are used by coal producers, coal preparation plants
and coal-fired power plants
to determine coal quality in real time. Coal quality parameters of greatest interest include ash, moisture, sulfur, and energy value (also known as heat content
). Although most coal operations can obtain this information about coal quality by taking physical samples, then preparing the samples and analyzing them with laboratory equipment, these processes often involve a time lag of up to 24 hours from gathering the sample to final analysis results. In contrast coal analyzers provide analysis information each minute on material being transported by conveyor either at the mine or the power plant. This timely coal quality information in turn allows the operator to improve his process by taking timely process control
actions, such as sorting, blending, or prep plant control.
There are three different types of coal analyzers. The most sophisticated analyzers use a technique known as prompt gamma neutron activation analysis (PGNAA)
to determine the elemental content of the coal. Bulk material analyzers
also use this technique in the cement industry. PGNAA permits analysis of sulfur and ash, and when combined with a second type of analyzer—the moisture meter—provides moisture and energy value as well. Moisture meters are often found in conjunction with the elemental analyzers, but sometimes are used alone, or in conjunction with ash gauges. Most moisture meters use microwave technology, while ash gauges exploit gamma attenuation principles.
Coal analyzers were first introduced in the early 1980s with the US and Australia leading the way. The demand for coal analyzers has been highest in the US, owing to the need to control sulfur as mandated by the Clean Air Act Amendments of 1977. By the year 2005 more than 600 coal analyzers were in use throughout the world. Most of these analyzers are mounted around an existing conveyor belt, although a significant minority analyze sample streams taken from the main process stream.
Coal preparation plant
A coal preparation plant is a facility that washes coal of soil and rock, preparing it for transport to market. A CPP may also be called a "coal handling and preparation plant" , "prep plant," "tipple," or "wash plant"....
and coal-fired power plants
Fossil fuel power plant
A fossil-fuel power station is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce electricity. Central station fossil-fuel power plants are designed on a large scale for continuous operation...
to determine coal quality in real time. Coal quality parameters of greatest interest include ash, moisture, sulfur, and energy value (also known as heat content
Enthalpy
Enthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.Enthalpy is a...
). Although most coal operations can obtain this information about coal quality by taking physical samples, then preparing the samples and analyzing them with laboratory equipment, these processes often involve a time lag of up to 24 hours from gathering the sample to final analysis results. In contrast coal analyzers provide analysis information each minute on material being transported by conveyor either at the mine or the power plant. This timely coal quality information in turn allows the operator to improve his process by taking timely process control
Process control
Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...
actions, such as sorting, blending, or prep plant control.
There are three different types of coal analyzers. The most sophisticated analyzers use a technique known as prompt gamma neutron activation analysis (PGNAA)
Prompt gamma neutron activation analysis
Prompt-gamma neutron activation analysis is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. It is a non-destructive method, and the chemical form and shape of the sample are...
to determine the elemental content of the coal. Bulk material analyzers
Bulk material analyzer
The term bulk material analyzer is the generic noun for that device which fits around a conveyor belt and conducts real-time elemental analysis of the material on the belt. Other names often found for such a device include belt analyzer, crossbelt analyzer and elemental analyzer...
also use this technique in the cement industry. PGNAA permits analysis of sulfur and ash, and when combined with a second type of analyzer—the moisture meter—provides moisture and energy value as well. Moisture meters are often found in conjunction with the elemental analyzers, but sometimes are used alone, or in conjunction with ash gauges. Most moisture meters use microwave technology, while ash gauges exploit gamma attenuation principles.
Coal analyzers were first introduced in the early 1980s with the US and Australia leading the way. The demand for coal analyzers has been highest in the US, owing to the need to control sulfur as mandated by the Clean Air Act Amendments of 1977. By the year 2005 more than 600 coal analyzers were in use throughout the world. Most of these analyzers are mounted around an existing conveyor belt, although a significant minority analyze sample streams taken from the main process stream.