[Objective

]

Against the backdrop of the transformation toward the new power system

coal-fired power units have shifted from traditional main power suppliers to “ballast stones” for power supply security and “stabilizers” for system regulation. However

deep peak regulation operation

characterized by frequent and rapid load changes and prolonged low-load conditions

poses significant challenges to the safe and stable operation of desulfurization systems and the compliance with pollutant emission standards. [Methods

]

To address these issues

this study innovatively developed targeted secondary evaluation parameters at first

including the difficulty in desulfurization slurry level control

desulfurization resistance coefficient

and applicability of desulfurization gypsum u

tilization pathways

thereby significantly enriching the existing monitoring and evaluation methods for desulfurization system operation. Secondly

taking a 1000 MW coal-fired power unit equipped with a limestone wet flue gas desulfurization system as the research object

this study conducted comprehensive and systematic evaluations on the desulfurization system's operating status

SO

2

emission characteristics

gypsum quality

and utilization under different load conditions using on-site test detection

online parameter monitoring

and the newly developed secondary evaluation parameters. [Results

]

The results indicate that under low-load(deep peak regulation) conditions: due to the sharp reduction in flue gas flow rate and notably poor flow field uniformity

the relative deviations between online monitoring values and experimental test values of SO

2

concentrations at the desulfurization outlet and total exhaust outlet expand to 11.1% and 16.9%

respectively; coupled with severe water balance imbalance and slurry foaming caused by unburned organics from oil-firing

the average difficulty in liquid level control increases by 75% compared with that at high load

with the maximum liquid level exceeding 9.8 m and highlighting prominent overflow risks; the blockage of demisters is significantly aggravated

contributing 47.4% and 59.4% respectively to the noticeable increase in resistance coefficients of the desulfurization system and demisters; fixed-frequency equipment such as slurry circulation pumps and oxidation fans cannot linearly adapt to load changes

leading to notably insufficient gas-liquid mass transfer and an 18%～25% increase in desulfurization specific energy consumption compared to other loads; oil-firing for stable combustion reduces the key effective component of desulfurization gypsum to 79.2% and increases free water and organic matter content

making it no longer applicable to major and mainstream utilization pathways such as gypsum board and cement retarder. [Conclusion

]

These

findings comprehensively reveal the multi-dimensional impacts of deep peak regulation on desulfurization systems

providing a solid theoretical basis and highly reliable data support for coal-fired power units to achieve economical

efficient

and environmentally friendly operation under deep peak regulation conditions.