On-Line Coal Monitoring

Stringent emissions limits and economic competition in an unregulated power generation market in the US have forced coal-fired plants that fire a specified type of coal to fire coals and fuel blends with different characteristics than the design coal.  Quantifying coal quality is essential for optimizing the including and availability of coal-fired power plants.  Researchers from Energy Research Company (ERCo)  of New Jersey and the Energy Research Center (ERC), with funding from the US DOE, have developed an on-line, over-the-belt system that measures coal composition and higher order coal properties, such as heating value and ash fusion temperature in real time.  The technology, named ERCoal™3000, uses Laser Induced Breakdown Spectroscopy (LIBS).  In a typical configuration a laser beam is directed onto the coal stream moving on the conveyor belt.  The pulsed laser vaporizes and ionizes micrograms of the coal.  Light from the resulting plasma is processed by a spectrometer, which records the wavelength and intensity of the signal.  The wavelengths uniquely identify each element and the intensities are proportional to their concentrations.  Artificial intelligence is then used to process the LIBS spectral data.

A commercial demonstration of the technology was performed at PPL Generation’s Montour Station.  An important aspect of this demonstration was the broad variability of the feedstock.  ERCoal™3000 was installed on a transfer conveyor belt.  Statistical analysis of the data using the ASTM D 6543 guideline showed excellent accuracy of the LIBS measurements.  A second commercial installation is underway, under funding from First Energy and EPRI, at Bruce Mansfield Power Plant.  The technology is being commercialized by the ERC and ERCo, and it offers advantages of smaller footprint, and lower installed and maintenance cost than other competing technologies.  The ERC has also developed application software that combines LIBS and plant data for improvements in unit operation, such as boiler slag mitigation.  Further funded research of the LIBS technology by EPRI, NYSERDA and Air Products has focused on biomass and MSW.

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