燃煤工业锅炉重金属排放特征研究

通过对6台燃煤工业锅炉污染物控制装置前后烟气中重金属浓度进行测试,考察了静电除尘器(ESP)、湿法脱硫装置(WFGD)和脱硫除尘一体化装置对烟气中重金属排放的影响。研究结果表明:ESP对烟气中的重金属有较好的捕集效果,对Pb、Cd、Cr的去除效率均为50%以上,通过对2台工业锅炉烟气中重金属排放测试发现,静电除尘器对Hg的去除率分别为45.70%和29.63%;经WFGD装置洗涤后,烟气中Hg、Pb、Cd的浓度均低于10μg/m3;脱硫除尘一体化技术对Hg、Pb和Cd的去除效果不明显,4号锅炉烟气脱硫后Pb的排放浓度高达65.76μg/m3。ESP+WFGD烟气处理装置较脱硫除尘一体化装备能够更好地控制烟气中重金属的排放。

STUDY ON EMISSION OF HEAVY METALS FROM THE COAL-FIRED INDUSTRIAL BOILERS

The concentration of heavy metals in the flue gas before and after 6 sets of typical pollution control system of coalfired industrial boilers were tested，and the removal efficiencies of the electrostatic precipitator ( ESP) ，wet flue gas desulfurization ( WFGD) system and the integrated desulfurization and dust removal unit on the heavy metals in flue gas were also studied． ESP shows great performance in heavy metals removal，and the efficiency of more than 50% can be attained for Pb，Cd and Cr． And as for Hg removal process of ESP of the No. 1 and No. 2 industrial boilers，the efficiencies are 45. 70% and 29. 63%，respectively． The concentrations of Hg，Pb and Cd are less than 10 μg /m3 in the outlet of WFGD system． The integrated desulfurization and dust removal unit slightly influences the removal efficiency of Hg，Pb and Cd，and the Pb emission concentration after the No. 4 industrial cleaning unit is as high as 65. 76 μg /m3 ． The heavy metals removal capacities for the ESP + WFGD are higher than that of the integrated desulfurization and dust removal unit．