Review on occurrence, speciation, transition and fate of sulfur in typical ultra-low emission coal-fired power plants

Sulfuric pollutants (SO2, SO3/sulfuric acid mist, sulfate, etc.) generated in coal-fired power plants (CFPPs) have been receiving more and more attention due to their adverse effects on the operation of power plant and environment. In order to abate air pollutants including sulfur (S) substance in flue gas, ultra-low emission (ULE) control technology was exploited to collaboratively capture these pollutants by using air pollutants control devices (APCDs), while S present in different occurrence in coal and various chemical speciation in flue gas when passing through APCDs. Therefore, it is necessary to clarify the transition and fate of S from in coal pre -combustion to in flue gas after APCDs. This paper reviews the transformation of S in the sequence of flowing in to flowing out in typical ULE-CFPPs, including the basic principles, influencing factors and recent studies on S pollutants generation, transformation and control. Firstly, the occurrence of S in coal and transition mechanism of S in boiler combustion are analyzed. Then, the mechanism and influencing factors of S substances deposited on heat recovery device, selective catalytic reduction (SCR), electrostatic precipitator (ESP), wet flue gas desul-furization (WFGD) and wet electrostatic precipitator (WESP) are discussed, and the influence of different S on the operation performance of each device is also discussed. Furthermore, the factors affecting the removal efficiency of S in APCDs are analyzed, and some suggestions are put forward for the optimal operation of APCDs.

Automated summary

The paper reviews the generation, transformation, and control of sulfuric pollutants in coal-fired power plants, with a focus on the application of ultra-low emission technology in air pollutant control. The occurrence and transformation mechanism of sulfur in different environments, as well as the factors influencing device performance, are analyzed throughout the whole process from coal combustion to the passage of flue gas through control devices. The factors affecting the removal efficiency of sulfur in APCDs are also discussed, and suggestions for optimizing operation are provided.