Insight into co-pyrolysis interaction of Pingshuo coal and low-density polyethylene under varied mixing configurations via in-situ Py-TOF-MS

摘要

The real-time detection of volatiles is crucial for exploring co-pyrolysis mechanisms. In this study, the co -pyrolysis interaction mechanism of Pingshuo coal (PC) and low-density polyethylene (LDPE) with three varied mixing configurations was explored based on the product distribution and stable radicals in char by using in-situ pyrolysis time-of-flight mass spectrometry with vacuum ultraviolet photoionization as well as electron para-magnetic resonance. Total ion currents results show that mixing configurations have an obvious impact on the release of volatiles. In the coal-LDPE test, the volatiles from coal promotes the cracking of long-chain branches in LDPE, resulting in high alkenes content. Meanwhile, the LDPE melts delay the release of coal volatiles causing a higher peak temperature of 478 ?. As for the LDPE-coal configuration, the LDPE volatiles has a better hydrogen -donor effect, which can interact with volatiles and char from coal pyrolysis to facilitate the formation of aro-matics and phenols. Comparatively, coal/LDPE configuration prompts the molten LDPE to coat coal particles and exhibits poor synergies between coal and LDPE. In addition, LDPE-coal char has higher spin concentrations of C-, and O-centered radicals, indicating that the released .H radicals from LDPE pyrolysis can well interact with char and unreleased volatiles in coal.