HFC-134a氧化热解的机理和实验研究  

Mechanism and Experimental Studies of HFC-134a Oxidative Decomposition Mechanism

作　　者：许云婷 张凯[1] 戴晓业[1] 史琳[1] Xu Yunting;Zhang Kai;Dai Xiaoye;Shi Lin(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing,100084,China)

机构地区：[1]清华大学能源与动力工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《制冷学报》2023年第3期29-40,共12页Journal of Refrigeration

基　　金：国家自然科学基金(52176011)资助项目;清华大学-山西清洁能源研究院创新种子基金项目资助

摘　　要：我国面临巨大HFCs制冷剂销毁压力,亟需研究高效且温和的HFCs制冷剂降解方法。本文结合实验与量子化学计算,以典型HFCs制冷剂HFC-134a为研究对象,以降解率为主要衡量标准,研究制冷剂降解的高效途径。从量子化学的角度,研究了HFC-134a自热分解与氧化热解条件下的反应路径,在两条路径下,均易产生CHF=CF_(2)与HF等可检测到的稳定产物。自热分解过程中,第一步化学键的断裂是决速步骤。氧化热解路径相较自热分解路径,反应能垒低,有利于反应快速发生。从实验的角度,发现在240~360℃温度范围内,随着温度的提高,HFC-134a的降解率由11%提高至66%,通过反应动力学常数拟合计算,得到HFC-134a的指前因子为7471.04 h^(-1),表观反应活化能为54.16 kJ/mol,与模拟计算所得化学反应能垒相吻合。There is significant emphasis on the destruction of HFC refrigerants in China,culminating in an urgent need to explore efficient and mild HFC refrigerant degradation methods.In this study,a typical HFC refrigerant,HFC-134a,was chosen as the object of combined experimental studies and quantum chemical calculations,and the degradation rate was considered the main criterion for exploring the high-level pathway of refrigerant degradation.In terms of quantum chemistry,the reaction paths of HFC-134a under pyrolysis and oxidative decomposition conditions were explored.Under both paths,detectable stable products such as CHF=CF_(2) and HF were easily produced.During pyrolysis,the first step in the chemical bond cleavage is the rate-determining step.Compared to the pyrolysis path,the oxidative decomposition path has a lower reaction energy barrier,which is conducive to the rapid occurrence of the reaction.Experimental results showed that the degradation rate of HFC-134a increased from 11%to 66%with the increase in temperature in the range of 240-360℃.By fitting the kinetic constant of the reaction,the pre-exponential factor(A)of HFC-134a was determined as 7471.04 h^(-1),and the activation energy(Ea)was 54.16 kJ/mol,which were consistent with the simulated chemical reaction energy barrier.

关 键 词：反应能垒 表观反应活化能 氧化热解 密度泛函方法 HFC-134A 

分 类 号：TB612[一般工业技术—制冷工程] TB64[动力工程及工程热物理—工程热物理] TK123[动力工程及工程热物理—热能工程]