摘要
在固定床反应器上,研究了不同种类有机固废在800−1100℃不同温度下燃烧/气化过程As、Pb的释放特性以及灰的组成成分,探究了CaO、SiO_(2)、Al_(2)O_(3)对气化过程中重金属As、Pb迁移转化的影响。结果表明,有机固废气化过程As、Pb的释放率整体上随温度升高而升高,且气化过程As、Pb的释放率明显低于燃烧;灰产率随温度升高而降低,灰中主要含有CaO、Al_(2)O_(3)和SiO_(2);热力学研究表明,在高温下气化过程主要生成气态As和Pb,而燃烧过程则会生成大量的As_(2)O_(3)和PbO,As和Pb的单质沸点相比氧化物更高,因此,气化过程As、Pb的释放率比燃烧过程要低;在900℃以下CaO、SiO_(2)、Al_(2)O_(3)会与As、Pb反应生成Ca_(3)(AsO_(4))_(2)、Ca_(2)PbO_(4)、PbSiO_(3)和AlAsO_(4),随着温度升高会逐渐分解,As、Pb的释放率逐渐升高,因此,气化温度应越低越好,并考虑适当增加有机固废中Ca、Si、Al含量,减少S、Cl含量来降低As、Pb在大气中的排放。
In a fixed bed reactor,the release characteristics of As and Pb and the composition of ash in the combustion/gasification process of different types of organic solid wastes at 800−1100℃were studied.The effects of CaO,SiO_(2) and Al_(2)O_(3) on the migration and transformation of heavy metals As and Pb in the gasification process were explored.The results show that the release rates of As and Pb in the organic solid waste gasification process increase with the increase of temperature on the whole,and the release rates of As and Pb in the gasification process are significantly lower than those in the combustion process.The ash yield decreases with the increase of temperature,and the ash mainly contains CaO,Al_(2)O_(3) and SiO_(2).Thermodynamic studies show that at high temperature,gasification process mainly produces gaseous As and Pb,while combustion process produces a large number of As_(2)O_(3) and PbO.The boiling points of As and Pb are higher than those of oxides,so the release rates of As and Pb in gasification process are lower than those in combustion process.Ca_(3)(AsO_(4))_(2),Ca_(2)PbO_(4),PbSiO_(3) and AlAsO_(4) can be produced by CaO,SiO_(2) and Al_(2)O_(3) reacting with As and Pb below 900℃.As the temperature increases,the release rates of As and Pb gradually increase.Therefore,the lower the gasification temperature is,the better it is.The emission of As and Pb in the atmosphere can be reduced by appropriately increasing the contents of Ca,Si and Al in organic solid waste and reducing the contents of S and Cl.
作者
李鹏程
张成
赵彦
余圣辉
方庆艳
陈刚
LI Peng-cheng;ZHANG Cheng;ZHAO Yan;YU Sheng-hui;FANG Qing-yan;CHEN Gang(State Key Laboratory of Coal Combustion,School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan,430074,China)
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2022年第8期1084-1092,共9页
Journal of Fuel Chemistry and Technology
基金
国家重点研发计划(2019YFC1906801)资助。
关键词
有机固废
气化
AS
PB
释放特性
热力学
organic solid waste
gasification
As
Pb
release characteristics
thermodynamic
