Thermal Decomposition and Oxidative Decomposition Mechanism of HFC-134a by Experimental and DFT Method  

作　　者：XU Yunting ZHANG Kai DAI Xiaoye SHI Lin 

机构地区：[1]Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Thermal Science》2024年第5期1990-2003,共14页热科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(52176011,52236003);the Creative Seed Fund of Shanxi Research Institute for Clean Energy,Tsinghua University。

摘　　要：In response to the Kigali Amendment to the Montreal Protocol and global low-carbon emission environmental requirements,the phase-out and decomposition of numerous HFC refrigerants have become urgent,necessitating efficient and mild decomposition methods.This study investigates the thermal decomposition and oxidative thermal decomposition pathways of the typical hydrofluorocarbon refrigerant HFC-134a,employing a combination of experimental and quantum chemical DFT simulation methods.Quantum chemical simulations reveal that the initial reaction bond cleavage serves as the rate-determining step during the thermal decomposition process,with the most easily detectable closed-shell products including CF_(2)=CHF,HF,CH_(3)F,CHF_(3),CH_(2)F_(2),and CF_(4).Reactive oxygen species can significantly reduce the Gibbs free energy barrier for HFC-134a decomposition.To achieve efficient degradation of HFC-134a,appropriate catalysts should be developed and selected to increase the level of reactive oxygen species in the reaction system.Experimental studies further corroborate that HFC-134a may undergo degradation through distinct reaction pathways under varying temperature(240℃to360℃)and pressure(0.1 MPa to 4.5 MPa)conditions,in agreement with simulation predictions.

关 键 词：HFC-134A PYROLYSIS oxidative thermal decomposition DFT REFRIGERANT 

分 类 号：TB64[一般工业技术—制冷工程] O641.1[理学—物理化学]