THERMAL SCIENCE

International Scientific Journal

INVESTIGATION ON ASH FOULING FORMATION OF INDUCED FAN BLADE AND HEAT EXCHANGER SURFACE IN A 1000MW COAL-FIRED POWER PLANT

ABSTRACT
The control of fouling deposition on the main equipment has always been an im-portant issue concerned by scientific research and industrial application. How-ever, severe fouling deposits on the induced fan blade and the low temperature economiser were found in a 1000 MW coal-fired power plant with ultra-low emission. The deposit samples were collected and analysed through X-ray dif-fraction spectrometer, X-ray fluorescence, elemental analyser and SEM with en-ergy dispersive spectrometers. The result shows that the deposits are mainly composed of tschermigite (NH4)Al(SO4)2 · 12H2O, letovicite (NH4)3H(SO4)2, cal-cium sulphate CaSO4, and quartz SiO2. The ammonium sulphate is the main component of the fouling deposits. It acts as an adhesive and makes an important contribution to the deposition. The analysis shows that the ammonia slip from denitrification system and the unreasonable temperature setting are the main reasons for fouling deposition. It is suggested that the high concentration of am-monium slip at denitrification system and the rapid condensation of the sulphuric acid mist at heat exchanger should be paid more attention in coal-fired power plants.
KEYWORDS
PAPER SUBMITTED: 2020-03-11
PAPER REVISED: 2020-03-27
PAPER ACCEPTED: 2020-04-15
PUBLISHED ONLINE: 2020-09-26
DOI REFERENCE: https://doi.org/10.2298/TSCI200311269L
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2020, VOLUME 24, ISSUE 6, PAGES [3477 - 3488]
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© 2020 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence