摘要
在某一大型医疗废物焚烧系统研究了选择性催化还原(SCR)装置的运行温度(200—350℃)对挥发性有机物(VOCs)大气排放的影响.采用固相吸附-热脱附/气相色谱-质谱法对SCR装置进口和出口处烟气中的VOCs进行分析.在焚烧烟气中共鉴定出46种VOCs,包括烷烃、烯烃、卤代烃、芳烃、醇、酮、醚、醛、酚、脂肪酸、脂肪酸酯、酰胺、硅氧烷和腈类化合物.在SCR装置进口烟气中鉴定出VOCs的总浓度均值为313.3μg·m^(-3).SCR装置的运行导致VOCs的大气排放浓度明显增加.当SCR装置运行温度为200℃和250℃时,排放烟气中鉴定出VOCs的总浓度均值分别增加了0.8倍和5.0倍.SCR装置的运行也显著改变了焚烧烟气中VOCs的组成分布.当SCR装置运行温度为200℃时,出口烟气中含氧VOCs的浓度大幅增加,尤其是酮和脂肪酸.当SCR装置运行温度为250℃和350℃时,排放烟气中鉴定出烷烃的平均浓度分别增加了15.6倍和3.7倍.导致SCR装置出口烟气中VOCs增加的主要原因可能为:VOCs没有被完全降解,半挥发性有机物经SCR催化剂催化后形成分子量更小的VOCs,较高的运行温度促进了VOCs从颗粒相向气相中迁移.
The effect of the operation temperature of selective catalytic reduction(SCR)equipment on the atmospheric emission of volatile organic compounds(VOCs)was investigated on a full-scale medical waste incineration system.Sorbent adsorption-thermal desorption/gas chromatography-mass spectrometry method was adopted to analyze the composition of VOCs in flue gases at the inlet and outlet of SCR equipment.A total of 46 VOCs were identified,including alkanes,olefins,halogenated hydrocarbons,aromatic hydrocarbons,alcohols,ketones,ethers,aldehydes,phenols,fatty acids,fatty acid esters,amides,siloxanes and nitriles.The average total concentration of identified VOCs in the inlet of SCR equipment was measured to be 313.3μg·m^(-3).The operation of SCR equipment induced an obvious increase in the emission concentration of VOCs.When the SCR equipment was operated at 200℃and 250℃,the average emission concentrations of total identified VOCs were increased by 0.8-fold and 5.0-fold,respectively.The operation of SCR equipment also induced a remarkable variation in the compositional distribution of VOCs in the flue gas.When the SCR equipment was operated at 200℃,the concentrations of oxygen-containing VOCs especially ketones and fatty acids in the flue gas at the outlet of SCR equipment were increased largely.When the SCR equipment was operated at 250℃and 350℃,the average emission concentrations of total identified alkanes were increased by 15.6-fold and 3.7-fold,respectively.The possible main reasons for the increase in the concentration of VOCs in the flue gas at the outlet of SCR equipment were speculated as:incomplete degradation of VOCs,transformation of semi-volatile organic compounds to VOCs with smaller molecular weight,temperature-induced transfer of VOCs from the particle phase into the gas phase.
作者
马慧莲
张海军
李德意
赵亮
曲健
田洪旭
王胜
陈吉平
MA Huilian;ZHANG Haijun;LI Deyi;ZHAO Liang;QU Jian;TIAN Hongxu;WANG Sheng;CHEN Jiping(CAS Key Laboratory of Separation Science for Analytical Chemistry,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,116023,China)
出处
《环境化学》
CAS
CSCD
北大核心
2022年第5期1530-1537,共8页
Environmental Chemistry
基金
国家自然科学基金(21707139,22076182)
中国科学院大连化学物理研究所创新基金项目(DICP I201937)资助。
关键词
挥发性有机物
固体废物焚烧
选择性催化还原
烟气
volatile organic compounds
solid waste incineration
selective catalytic reduction
flue gas
