Title: Effect of ambient air temperature on the performance of regenerative air preheater of pulverised coal fired boilers

Authors: Chittatosh Bhattacharya; Bidesh Sengupta

Addresses: Department of B.Tech (Power Engineering), National Power Training Institute, (Eastern Region), Michael Faraday Street, City Centre, Durgapur-713216; West Bengal, India ' Engineering – Rotary Air Preheaters, Alstom India Ltd., Tech Boulevard, Tower-C, Plot#6, Sector-127, Noida, UP, India

Abstract: The air preheater (APH) is the last heat trap in flue gas path of boiler. Efficient performance of APH is possible with efficient pre-combustion coal drying and effective combustion in the furnace. The characteristic of ambient air temperature (AAT) has a significant role on the efficiency of heat transfer in APH. The change in AAT in turn changes heat capacity of air that depends on relative humidity (RH) and air density. An increase in AAT will reduce the waste heat recovery opportunity, if sufficient reserve capacity of heat exchange is not available in APH. Besides, change in AAT will have an impact on the power consumption of the fans and leakage through different seals. In this paper, the effect of these factors due to change in AAT is evaluated to assess the performance of regenerative APH with reference to a field study of 135 MWe subcritical steam power plant.

Keywords: regenerative air preheaters; ambient air temperature; relative humidity; air density; moisture; coal drying; drying energy economics; pulverised coal; coal fired boilers; combustion; heat transfer; waste heat recovery; energy consumption; fans; seal leakage; performance evaluation; subcritical steam power plants.

DOI: 10.1504/IJETP.2016.075672

International Journal of Energy Technology and Policy, 2016 Vol.12 No.2, pp.136 - 153

Received: 21 Feb 2014
Accepted: 19 Mar 2015
Published online: 31 Mar 2016 *

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