College of Mechanic and Electronic Engineering, Qingdao University, Shandong, 266071, China.
College of Mechanic and Electronic Engineering, Qingdao University, Shandong, 266071, China.
J Hazard Mater. 2021 Jan 5;401:123302. doi: 10.1016/j.jhazmat.2020.123302. Epub 2020 Jun 24.
In this study, reaction molecular dynamics were combined with experiments to gain in-depth understanding of the gaseous pyrolysis products generation mechanism and optimal paths during natural rubber (NR), styrene-butadiene rubber (SBR) and mixed rubbers (NR-SBR) for effective recovery of waste rubber. The results show that the pyrolysis temperature of NR increases gradually with SBR addition. The monomers produced during the initial stage of SBR pyrolysis are mainly 1,3-butadiene and styrene, in which the energy barriers of the formed H and CH=CH in styrene are higher than those in 1,3-butadiene, and during further pyrolysis the main gas products are H and CH. During co-pyrolysis of NR-SBR, the reaction paths show that increasing H yield and decreasing CH yield take place easily as SBR content rises. By contrast to pyrolysis of NR, the path of generating CH=CH in SBR is more difficult while that of CH=CH abstracting H occurred easily, leading to first enhancement in produced CH=CH followed by a decline. Fixed bed experiments and gas chromatography (GC) analysis identify the main gas products of the three rubbers (NR, SBR, NR-SBR)as H, CH and CH=CH and the change of yield caused by the increase of SBR content are consistent with the simulation results.
在这项研究中，反应分子动力学与实验相结合，深入了解天然橡胶（NR）、丁苯橡胶（SBR）和混合橡胶（NR-SBR）在有效回收废橡胶过程中气态热解产物生成机制和最优路径。结果表明，随着 SBR 添加量的增加，NR 的热解温度逐渐升高。SBR 热解初期生成的单体主要是 1,3-丁二烯和苯乙烯，其中苯乙烯中形成的 H 和 CH=CH 的能垒高于 1,3-丁二烯，进一步热解时主要气体产物为 H 和 CH。在 NR-SBR 共热解过程中，反应路径表明随着 SBR 含量的增加，H 产率增加、CH 产率降低的趋势更容易发生。与 NR 热解相比，SBR 中生成 CH=CH 的路径更困难，而 CH=CH 夺取 H 的反应更容易发生，导致生成的 CH=CH 先增加后减少。固定床实验和气相色谱（GC）分析确定了三种橡胶（NR、SBR、NR-SBR）的主要气体产物为 H、CH 和 CH=CH，SBR 含量增加引起的产率变化与模拟结果一致。
