Continuous DeNOx Technology for Improved Flexibility and Reliability of 1000 MW Coal-Fired Power Plants: Engineering Design, Optimization, and Environmental Benefits

Abstract

This study endeavors to enhance the operational efficiency of extant coal-fired power plants to mitigate the adverse environmental impact intrinsic to the prevalent utilization of coal-fired power generation, which is particularly dominant in China. It focuses on the assessment and optimization of continuous denitrification systems tailored for a 1000 MW ultra-supercritical pulverized coal boiler. The extant denitrification framework encounters challenges during startup phases owing to diminished selective catalytic reduction (SCR) inlet flue gas temperatures. To ameliorate this, three retrofit schemes were scrutinized: direct mixing of high-temperature flue gas, bypass flue gas mixing, and high-temperature flue gas mixing with cold air. Each option underwent meticulous thermodynamic computations and comprehensive cost analyses. The findings elucidated that bypass flue gas mixing, involving the extraction and blending of high-temperature flue gas, emerged as the most financially prudent and practical recourse. This scheme optimizes fuel combustion heat utilization, significantly curtails fuel consumption, and fosters efficient internal heat transfer mechanisms within the boiler. The evaluation process meticulously considered safety parameters and equipment longevity. The insights derived from this investigation offer valuable guidance for implementing continuous denitrification system retrofits in industrial coal-fired power plants.