Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation,North China Electric Power University

城市污泥和煤矸石在燃烧性质上存在着一定互补性,而二者均含有大量重金属汞污染物,因此有必要研究二者掺烧过程中汞的迁移转化特性。采用化学逐级提取法,研究污泥与煤矸石样品中汞的赋存形态及燃烧过程中汞释放特性,并考察温度、掺混比例和气氛对于样品中汞迁移行为的影响。结果表明,1号污泥主要以硫酸盐、碳酸盐和氧化物结合态汞和残渣态汞为主;2号污泥中残渣态汞含量最高;煤矸石中主要以硫化物结合态汞为主。污泥中低温区(200~390℃)释放的汞主要为有机物结合态和碳酸盐结合态汞,高温区(390~450℃)释放的汞主要为硫化物结合态汞;煤矸石中低温区(300~400℃)释放的汞主要为有机物结合态、碳酸盐结合态和氧化物结合态汞,高温区(400~600℃)释放的汞主要为硫化物结合态及部分氧化物结合态。污泥掺混促使掺混物中汞提前在低温区释放,且随污泥掺混率提高,促进作用越强。气氛中氧含量升高,燃烧过程中产生的CO2会吸附在颗粒表面,增大传热热阻,从而抑制掺混物中有机物结合态汞和部分碳酸盐结合态汞的释放,同时发现气氛对高比例污泥掺混物汞的释放行为影响减弱。

There is a certain degree of complementarity between municipal sludge and coal gangue in combustion properties, and both contain a large amount of heavy metal mercury pollutants. Therefore, it is necessary to study the migration and transformation characteristicsof mercury in the mixed combustion process. The occurrence forms of mercury in sludge and coal gangue samples, as well as the release characteristics of mercury during combustion were studied by chemical step extraction method, and the effects of temperature, mixingratio and atmosphere on the migration behavior of mercury in the samples were investigated. The results show that No.1 sludge is mainly composed of sulfate, carbonate and oxide-combined mercury and residual mercury. The content of residual mercury in No.2 sludge isthe highest. The main content of coal gangue is sulfide-bound mercury. The mercury released in the low temperature zone of sludge from200 ℃ to 390 ℃ is mainly organic and carbonate bonded mercury, while the mercury released in the high temperature zone from 390 ℃ to450 ℃ is mainly sulfide bonded mercury. The mercury released by gangue at low temperature ranging from 300 ℃ to 400 ℃ is mainly organic binding, carbonate binding and oxide binding states, while the mercury released at high temperature ranging from 400 ℃ to 600 ℃is mainly sulfide binding and some oxide binding states. The release of mercury in coal gangue at low temperature in advance is promoteddue to sludge mixing, and the promotion effect becomes stronger with the increase of sludge mixing rate. With the increase of oxygen content in the atmosphere, CO2 produced in the combustion process will be adsorbed on the surface of the particles and the heat transfer resistance is increased, thus inhibiting the release of organic-bound mercury and some carbonate-bound mercury in the mixture. Meanwhile, it is found that the effect of atmosphere on the release behavior of mercury in the high proportion of sludge mixture is weakened.

国家重点研发计划资助项目(2020YFB0606201);国家自然科学基金与山西煤基低碳联合基金重点资助项目(U1910215)

段旺智,张凯华,张锴.城市污泥与煤矸石掺烧过程中汞的迁移转化特性[J].洁净煤技术,2023,29(11):83-90.

DUAN Wangzhi, ZHANG Kaihua, ZHANG Kai. Migration and transformation characteristics of mercury during mixingof municipal sludge with coal gangue[J].Clean Coal Technology,2023,29(11):83-90.