Errors Associated With Excess Air Multipoint Measurement Systems

• Autorzy: Ramsunkar C. , Tonder C. von , Schmitz W.

Identyfikatory

DOI

10.1515/cpe-2015-0029

• Języki publikacji: EN

Abstrakty

EN

Boiler combustion air is generally controlled by the excess air content measured at the boiler economiser outlet using oxygen (O2) analysers. Due to duct geometry and dimensions, areas of high and low O2 concentrations in the flue gas duct occur, which poses a problem in obtaining a representative measurement of O2 in the flue gas stream. Multipoint systems as opposed to single point systems are more favourable to achieve representative readings. However, ash blockages and air leakages influence the accuracy of O2 measurement. The design of multipoint system varies across ESKOMs’ Power Stations. This research was aimed at evaluating the accuracy of the multipoint oxygen measurement system installed at Power Station A and to determine the systematic errors associated with different multipoint systems designs installed at Power Stations' A and B. Using flow simulation software, FloEFDTM and Flownex®, studies were conducted on two types of multipoint system designs This study established that significantly large errors, as high as 50%, were noted between the actual and measured flue gas O2. The design of the multipoint system extraction pipes also introduces sigdnificant errors, as high as 23%, in the O2 measured. The results indicated that the sampling errors intro- introduced with Lethabo's system can be significantly reduced by adopting the sampling pipe design installed at Camden.

Słowa kluczowe

EN

excess air measurement; flue gas oxygen concentration; boiler O2; air ingress

PL

nadmiar pomiaru powietrza; stężenie tlenu spaliny; kocioł O2; wnikanie powietrza

• Wydawca: Komitet Inżynierii Chemicznej i Procesowej Polskiej Akademii Nauk
• Czasopismo: Chemical and Process Engineering
• Rocznik: 2015
• Tom: Vol. 36, nr 4
• Strony: 405--–423
• Opis fizyczny: Bibliogr. 9 poz., rys., tab.

Twórcy

autor

Ramsunkar C.

• ESKOM SOC, Lethabo Power Station, Vereeniging, Deneysville, Free State, South Africa

autor

Tonder C. von

• ESKOM SOC; Group Technology & Commercial Division, Sunninghill, Johannesburg, Gauteng, South Arica

autor

Schmitz W.

• University of Witwatersrand, School of Mechanical, Industrial and Aeronautical Engineering, Johannesburg, Gauteng, South Africa

Bibliografia

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• 4. ESKOM, 2012. Fossil fuel firing regulations. Regulation edn, Coal Fired Power Stations, ESKOM, Generation Division.
• 5. Innami Y., Murata, A., Yuki Y., Yoshimura E., 2011. Real-time CO measurement in a coal fired boiler with a TDLS analyser. SICE Annual Conference 2011, Yokogawa Electric Corporation, Tokyo, Japan, September 13–18, p. 92.
• 6. Molloy R.C., 1981. Microprocessor based combustion monitoring and control systems utilizing in-situ opacity, oxygen, and CO measurement. The Third Industrial Energy Technology Conference Houston Dynatron Inc., Wallingford, Connecticut, April 26–29, p. 333.
• 7. Scott J., Dennis B., 2010. Practical issues of combustion oxygen measurement specifically related to NOx emissions, Yokogawa Corporation of America, USA. Paper no: PWR2004-52045. Available at: www.yokogawa.com/us/technical-library/white-papers/practical-issues-in-combustion-o2-measurement-specifically-related-to-nox-emissions.htm
• 8. Van Wyk D.C., 2007. Feasibility Study Report. ESKOM, Matimba Power Station, Limpopo, RSA.
• 9. Yokogawa 2008, Carbon monoxide measurement in coal-fired power boilers. Yokogawa Corporation of America, USA. Available at: http://cdn2.us.yokogawa.com/TDLS_A_001.pdf.