Migration and Emission Characteristics of Trace Elements in a 660 MW Coal-Fired Power Plant of China

Abstract

11Trace elements (TEs) emitted from coal-fired power plant has caused widespread 12 concern. The onsite investigation of the TEs emission from a Chinese 660MW 13 pulverized coal (PC) boiler equipped with SCR, ESP, WFGD and WESP was 14 conducted by using US EPA Method 29. Simultaneous sampling of the coal, bottom 15 ash, ESP ash, flue gas and by-products from WFGD and WESP process was 16 performed. Results show that TEs mass balance rates for the entire system, furnace 17 and each air pollution control device (APCD) are in acceptable range of 70-130%, 18 which confirms the validity and reliability of the field test data. The studied TEs are 19 mainly distributed in bottom and ESP ash with the ratio of 2.11%-12.15% and 20 87.83%-97.83% respectively while little amount of them exists in WFGD, WESP and 21 stack. Coal combustion by-products like bottom ash and gypsum have little influence 22 on soil from the perspective of TEs while more attention should be paid to Ni, Zn and 23 Cd in the ESP ash. Waste water from WFGD should be treated carefully especially 24 for Cr and Mn. WESP waste water has no influence on ground water except Mn, Ag 25 and Sb. Zn, Ni and Sb prefer to enrich in ESP ash while accumulation of Mn occurs in 26 bottom ash. Ba is enriched in both bottom and ESP ash. ESP has great removal 27 efficiency for TEs with value exceeding 99.87%. Both WFGD and WESP are capable 28 to capture TEs, which results in the overall removal rate across ESP + WFGD + 29 WESP more than 99.90%. TEs concentration in the flue gas emitted from the stack is 30 extremely low with the range of 0.00-1.33 µg/m 3 . The ultra-low emission (ULE) 31 coal-fired power plant equipped with SCR + ESP + WFGD + WESP has good effects 32 on TEs emission control.33

Enrichment Mechanisms of Gallium and Indium in No. 9 Coals in Anjialing Mine, Ningwu Coalfield, North China, with a Preliminary Discussion on Their Potential Health Risks

“…It has been confirmed that CFA conducts as a carrier of hazardous trace elements (HTEs) [133,134]. Although fabric filter or electrostatic precipitator had been widely equipped in smokestacks of power plants, PM with various assemblies of HTEs caused by CFA releasing still resulted in high risk on atmospheric environment and human health [135][136][137][138][139]. Dwivedi et al [140] found that oxidative DNA damage in human cells was attributed to nanoscale CFA.…”

Partitioning behavior of Arsenic in circulating fluidized bed boilers co-firing petroleum coke and coal

“…Here the ratios are in the range of 80.0%~114.2%, and the relative deviations of the mass balance are in the range of 6.2%~8.1%. Because of the slight variation of boiler operating conditions, the fluctuation of components in solid and liquid samples and the complexity and uncertainty in sampling and analysis process, values in the range of 70%~130% are acceptable [42][43][44]. An analysis of these data suggests the current study can be considered reliable and satisfactory.…”

Investigation on ash fouling formation of induced fan blade and heat exchanger surface in a 1000MW coal-fired power plant

“…According to the coal properties and ash compositions, the acid dew point of the flue gas can be estimated using thermodynamic method, which is given as follows: fh ar ,zs 3 ar,zs…”

“…With the improvement of ecological environment awareness, the impacts of pollutant emission from coal-fired power plants on frequent haze weather have gradually attracted attention [1,2]. Currently, China has fully carried out strict ultra-low emission standard for coal-fired power plants, which specifies particulate matter (PM), sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) shall not exceed 5, 35 and 50 mg/Nm 3 [3]. Correspondingly, the technologies that achieve the ultra-low emission target through a series of processes or devices are called ultra-low emission technologies.…”