Applied Technologies to Improve Coal-Fired Power Generation

Economic and operational performance can be enhanced when power generation operators know the coal’s quality as it comes from the mine or through the preparation plant. Online elemental analyzers can use either Prompt Gamma Neutron Activation (PGNAA) or Pulsed Fast Thermal Neutron Activation (PFTNA) technology to help provide coal producers with accurate, reliable data to control coal blends and ensure on-spec batches and more efficient use.

PGNAA and PFTNA are noncontact, non-destructive analytical techniques used in online analysis systems to determine the elemental composition of coal. Both of these techniques are known collectively as neutron activation analysis and function by bombarding materials with neutrons.

Using PGNAA/PFTNA to analyze the incoming coal delivers valuable information on levels of sulfur, moisture, total ash, calorific value, ash elemental concentration, and other critical parameters. This information is used to help maximize the use of resources, enable optimal blending for precise burn and temperature requirements, and reduce pollutants.

X-ray fluorescence spectroscopy (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. XRF analyzers work by measuring the fluorescent (or secondary) X-rays emitted from a sample when excited by a primary X-ray source. Each element present in a sample produces a set of characteristic fluorescent X-rays, or “unique fingerprints.” These fingerprints are distinct for each element, making XRF analysis an excellent tool for quantitative and qualitative measurements of materials.

Handheld XRF analyzers enable positive material identification (PMI) on infrastructure in the plant, such as piping material, to help ensure it does not contain incorrect or out of specification metal alloys that could lead to failure. This technique can be used effectively by manufacturers who supply the piping before they are shipped to the power plant as well as to verify and spot check on site.

Laser Induced Breakdown Spectroscopy (LIBS) is an analytical technique used to determine the elemental composition of materials. Handheld LIBS analyzers work by using a high-focused laser to ablate the surface of a sample. A plasma is formed consisting of electronically excited atoms and ions. As these atoms decay back into their ground states, they emit characteristic wavelengths of light. These wavelengths are distinct for each element, making handheld LIBS analysis an excellent tool for quantitative and qualitative measurements.

Like handheld XRF instruments, LIBS analyzers are used to perform positive material identification (PMI) on any piping material in the power plant to help ensure it does not contain incorrect or out of specification metal alloys. However, LIBS is capable of quantifying carbon and is especially suited for positive material identification (PMI) of piping, pressure vessels, valves, pumps, and finished welds, or to grade unknown materials to regain traceability – as well as measuring silicon in steel for sulfidic corrosion or residual elements in HF Alkylation process components.

Mining industries and those that utilize mined minerals as raw materials are exposed to a variety of naturally occurring radiation sources.  Coal naturally contains trace amounts of radioactive elements. And because of the extensive use of radioactive measurement and analysis techniques (e.g. X-ray and Gamma ray analyzers) in power generation plants, the potential for exposure to personnel increases dramatically. Both natural and man-made sources of radiation are potentially dangerous and life threatening if not managed appropriately. 

Detection of various types of radiation throughout the process is paramount to worker safety and quality control. Radiation detection technology can be delivered by way of multiple devices, each suited for the type of radiation to be monitored, the environmental circumstances and source. 

Handheld radiation detection devices provide real time detection of gamma radiation with accurate dose rate measurements, verify the radioactive find, and assess whether radioactivity is of natural or artificial origin. Portable devices with high sensitivity neutron response and alarm threshold can be worn to monitor gamma sensitivity and energy compensated dose rate measurement.

The burning of coal releases many pollutants, including sulfur dioxide (SO₂) and various particulate matter. The smokestacks from these power plants also emit greenhouse gases, such as carbon dioxide (CO₂) and methane (CH₄), which are detrimental to the environment and health.

To help alleviate these concerns and adhere to regulatory compliance, coal-fired power plants utilize technology to reduce the output of these harmful substances.  Continuous Emissions Monitoring Systems (CEMS) are used to monitor Particulate Matter (PM) and Mercury (Hg) among other substances. The system includes probes that are installed in stack and transfer gas to PM and Hg analyzers in the shelter, helping coal-fired power plants to comply with local PM and Hg emission regulation and achieve optimal process performance.