基于实测的燃煤电厂氟排放特征

选择我国4家电厂的6台煤粉锅炉,进行了烟气以及飞灰、底渣、脱硫石膏等燃煤副产物样品的采集和F(氟)含量分析,考察燃煤电厂F排放特征. 结果表明:经过烟气除尘、脱硫及脱硝装置后,烟气中氟化物浓度明显降低； 除尘器主要脱除烟气中颗粒态F,静电除尘器对烟气中氟化物的总脱除效率为19.50%~36.59%,布袋除尘器的脱除效率略高于静电除尘器；石灰石-石膏湿法脱硫装置可协同脱除烟气中94.19%的氟化物. 燃煤中的F经过燃烧和烟气净化装置后,有0.83%~3.37%由底渣排放；1.20%~2.00%转移到脱硫废水中；13.45%~33.80%转移到飞灰中；59.60%~79.66%转移到脱硫石膏中；只有2.04%~5.00%通过烟囱排入大气. 

Fluorine Emission of Pulverized Coal-Fired Power Plants in China

Fluorine is a trace element in the coal and may cause environmental and human healthy problems during coal combustion. While coal-fired power plant is one of man-made sources of fluorine emissions in China, fluorine emission behaviors from coal-fired power plants have not been comprehensively investigated until now. A full-scale field study of fluorine emissions was conducted at six pulverized coal-fired boiler (PC) units of four coal-fired power plants in China. Flue gases were sampled from the inlets and outlets of the existing air pollutant control devices (APCDs) to investigate their effects on speciation and distribution of fluorine in the flue gas. Concurrent with flue gas, coal, bottom ash, fly ash and samples from the FGD process (desulfurization gypsum and waster water) were collected. Over 96.63% of fluorine contained in coal were released during the combustion process in the examined PC boilers, and fluorine compounds in flue gas were mainly in the form of HF. Wet FGD and dedusting devices were able to remove fluorine compounds in flue gas, wet FGD being more effective. Particulate bound fluorine in flue gas can be removed by dedusting devices. The removal efficiency of dedusting devices varied from 19.50% to 36.59% for fluorine compounds in flue gas. Bag-house filters were effective than electrostatic precipitators (ESP). Most of HF in flue gas can be removed by wet FGD devices and the average removal efficiency of wet FGD devices was 94.19%. The fluorine released from coal combustion was transferred into slag, fly ash, desulfurization gypsum and the waste water after passing through the devices for air pollution control. Fluorine in slag ranged from 0.83% to 3.37%, and approximately about 13.45%-33.80% of fluorine were contained in fly ash. A proportion of 59.60%-79.66% of fluorine came into the gypsum while the waste water was kept 1.20%-2.00% of the total fluorine. Only 2.04%-5.00% of fluorine were directly emitted into the atmosphere.