Optimal boiler control through real-time monitoring of unburned carbon in fly ash by laser-induced breakdown spectroscopy

Abstract

A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash.

Multi-Sensor Fusion Using Knowledge-based Mind Evolutionary Algorithm

“…Unburned carbon content in fly ash is an important parameter to reflect the economy of the boiler combustion directly in the pulverized-coalfired power plant [7] . When the UBC levels is high, it will result in not only the increase of the consumption of coal, followed by the increase of the cost of generating electricity, but the increase of the discharge of NO x and environmental pollution as well.…”

Breakdown Pattern of Hydrocarbons by Laser Breakdown Time-of-flight Mass Spectrometry

“…With the development of laser and detection systems, LIBS has been widely applied for composition measurement in gas, [13][14][15] liquid, [16][17][18] and solid materials. [19][20][21][22][23][24] Especially, the advantages of the method are its applicability to various fields such as combustion, metallurgy, and the harsh environment. However, LIBS applicability cannot reach the trace species detection needs due to the restriction of its detection limit (ppm-ppb).…”

Quantitative carbon measurement in anthracite using laser-induced breakdown spectroscopy with binder

“…As the laser shots on the coal surface, the volatile components are vaporized and ignited in the atmosphere of air, leading to more measurement uncertainty to the elemental analysis of coal including carbon. Carbon concentration measurement has been reported in fly ash [9] and flue gas [10] in operating conditions. Yu et al [11] analyzed carbon in coal directly but with only six pulverized coal samples.…”