Investigation on the improvement of the combustion process through hybrid dewatering and air pre-heating process: A case study for a 150 MW coal-fired boiler

Abstract

In this study, a parametric advanced exergy analysis was conducted for the waste heat recovery of a pulverized coal-fired power plant. In this aim, a new attainable ideal and the technically available unavoidable case for the combustion process were identified. Under the identified improved potential term, different unavoidable cases were parametrically investigated for the hybrid dewatering and air preheating process to improve the combustion process. In this aim, different removed moisture contents, air preheating conditions, and effectiveness of both internal and external heat exchangers were thermodynamically evaluated in terms of the combustion process. The improved potential was calculated as 74.4% for the whole combustion system. The critical moisture removal ratio was calculated as 20%. The effects of rehabilitation on improved potential were found as 2.80 points per 1% of effectiveness increase for the self (internal) heat exchangers of the boiler, 1.68 points per 1% of effectiveness increase for HE-I and HE-II (external heat exchangers), and 0.62 points per 1% increase of dewatered moisture ratio. Besides, a saving of about 29.54% was determined in fuel consumption for the most appropriate unavoidable condition. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.