对氯苯酚超临界水脱氯的反应动力学及机理分析  

Dechlorination kinetics and mechanism of p-chlorophenol in supercritical water

作　　者：韦朝海[1] 李登勇[1] 施华顺[1] 关清卿[1] 胡芸[1] 

机构地区：[1]华南理工大学环境科学与工程学院,广州510006

出　　处：《中国科技论文在线》2010年第6期441-447,共7页

基　　金：高等学校博士学科点专项科研基金资助项目(20090172110028);国家自然科学基金资助项目(20777018);"十一五"国家科技支撑计划重点资助项目(2008BAC32B06-1)

摘　　要：在反应温度400~460℃、压力24MPa、停留时间30~200s,过氧量100%~500%的条件下,分析了对氯苯酚（4-CP）在等温立式柱塞流反应器中的超临界水氧化脱氯反应动力学及机理。首先得出温度为440℃、压力为24MPa、过氧量375%时,4-CP脱氯率可以达到80%的反应效果;过程显示,随着停留时间增大、温度提高,4-CP脱氯率提高,4-CP初始质量浓度和过氧量变化对过程无显著影响;动力学研究发现,4-CP的超临界水氧化技术（SCWO）反应动力学过程符合幂指数方程,通过参数拟合,求得4-CP反应级数为1,H2O2的反应级数为零,反应活化能为92.978KJ·mol-1,指前因子为104.6302,动力学方程能较好地预测实验结果;最后,通过GC/MS方法定性分析的反应中间产物为对苯二酚、邻苯二酚和对苯醌等,推测反应过程中伴随自由基参加的偶合反应占主导。研究结果证明了4-CP的超临界水氧化脱氯过程可行与高效,可望成为工艺应用的基础。The supercritical water oxidation（SCWO） dechlorination kinetics and mechanism of p-chlorophenol（4-CP） was studied in an isothermal and vertical plug-flow reactor at 400-460 ℃,24 MPa,residence time of 30-200 s,and excess oxygen of 100%-500%.The results showed that the dechlorination rate of 4-CP could reached 80% at 440 ℃,24 MPa and excess H2O2 375%.The dechlorination rate increased with the increase in the temperature and residence time,while it did not obviously change by the initial concentration of 4-CP and excess H2O2.It was found that kinetics for dechlorination of 4-CP was described by a rate law involving first order reaction of 4-CP,zero order reaction of H2O2,92.978 KJ·mol-1 of activation energy,and 104.6302 of Arrhensius pre-exponential factors.The experimental results were forecasted well by the kinetics equation through repeated experiments.The results of GC/MS analysis showed that hydroquinone,catechol and benzene hydroquinone were the major intermediates and the reaction process included the coupling of free radicals.The research revealed the dechlorination process and mechanism of 4-CP in supercritical water and was expected to provide the basis for the engineering application of SCWO technology.

关 键 词：4-CP 超临界水(SCW) 脱氯 动力学 反应机理 

分 类 号：X703[环境科学与工程—环境工程]