矿物添加剂对煤燃烧过程中重金属的富集  

Enrichment of heavy metals during coal combustion by mineral additives

作　　者：马杨杨 仲兆平[1] 赖旭东 MA Yangyang;ZHONG Zhaoping;LAI Xudong(College of Energy and Environment,Southeast University,Nanjing 210096,Jiangsu,China)

机构地区：[1]东南大学能源与环境学院,江苏南京210096

出　　处：《化工进展》2020年第6期2479-2486,共8页Chemical Industry and Engineering Progress

基　　金：国家重点研发计划(2018YFB0605102)。

摘　　要：在管式炉中进行了煤与矿物添加剂的燃烧实验,研究了900~1300℃的高温条件下,质量添加比分别为0、1%、3%和5%,高岭土、蒙脱石、凹凸棒土和石灰石对重金属元素Pb、Cd、Zn和Cr的富集效果。结果表明:随着添加剂比例的增加,各重金属的固留率均呈上升趋势,且添加比以5%为宜。添加剂对Pb和Cd的富集温度为900~1000℃较为适宜,该温度范围内二者的固留率保持在60%左右,对Zn富集的适宜温度为900℃,该温度下Zn的固留率接近70%,Cr为1000~1100℃,固留率可达到82.1%。当温度达到1100℃时,煤灰的结焦会导致四种重金属的固留率均有所下降,当温度升高到1200℃时固留率将大幅度下降,1300℃时各添加剂几乎完全失活,其中Pb的固留率只有大约25%,Cd和Zn的固留率降低到30%左右,Cr的固留率下降至56%以下。对比4种添加剂对Pb、Cd、Zn和Cr的富集效果而言,高岭土和凹凸棒土的性能较优,蒙脱石次之,石灰石较差。本研究能够为燃煤电厂重金属的污染控制提供理论和实验依据。Experiences of pulverized coal combustion with different mineral additives were carried out in a tube furnace.When the mass addition ratio of the four mineral additives(Kaolin,montmorillonite,attapulgite and limestone)were 0,1%,3% and 5%,the enrichment effects of heavy metals(Pb,Cd,Zn and Cr)were studied at 900-1300℃.The results indicate that there exists a positive correlation between the addition of additives and the retention rate of each heavy metal,and the addition ratio of 5%is more suitable.The suitable enrichment temperature range of the additives for Pb and Cd is 900-1000℃.The retention rates of Pb and Cd are maintained at approximately 60% in this temperature range.The suitable temperature for Zn enrichment is 900℃.The retention rate of Zn is close to 70% at this temperature.The temperature range for Cr is 1000-1100℃,and the retention rate of Cr can reach 82.1%.When the temperature reaches 1100℃,the coking of coal ash will lead to a decrease in the retention rate of the four heavy metals.When the temperature rises to 1200℃,the retention rate will drop significantly;the additives are almost completely inactivated at 1300℃;and among them,the retention of Pb is only about 25%,the retention of Cd and Zn is reduced to approximately 30%,and the retention of Cr is reduced to 56% or less.Comparing the enrichment effects of the four additives on Pb,Cd,Zn and Cr,Kaolin and attapulgite have better performance,followed by montmorillonite and limestone is the last.This study can provide theoretical and experimental basis for pollution control of heavy metals in coal-fired power plants.

关 键 词：矿物添加剂 煤燃烧 重金属元素 添加比 富集温度 

分 类 号：X506[环境科学与工程—环境工程]