Characterization of ash deposits from the boiler of Yenikoy coal-fired power plant, Turkey

Yenikoy power plant is a coal-fired electric power station with a 2 × 210 MW production capacity located in Mugla, Turkey. The plant burns a low quality, high calcium lignite, which causes significant operational problems due to slag formation in combustion units over time. This study aimed to characterize the ash deposits taken from one of the boilers of this particular power plant. The samples were collected from different elevations of the boiler and subjected to chemical, mineralogical and micro-textural analyses. Apart from Ca, significant concentrations of Fe, Al and Si were detected in ash deposits. Anhydrite was found to be the dominating crystalline phase and various forms of aluminosilicates, iron-oxide crystals and Fe–Ca bearing phases were also identified in the samples. The deposits basically consist of two layers; the inner layer characterized by a reddish-colored surface with high hematite content and the outer layer which was mostly in gray and light brown color due to the presence of high amount of calcium particles.

► Yenikoy power plant uses a low quality, high-calcium lignite.
► The samples subjected to mineralogical, microstructural, and chemical analysis
► According to the chemical analyses, deposits contain high amount of CaO.
► Ash deposits were mainly composed of various forms of CaSO4.
► The results suggested an ash deposition mechanism involving calcium-fluxed oxides.