重质有机资源热解过程中的自由基化学

热解是煤炭、油页岩、重油、生物质以及有机废物等重质有机资源生产燃料和化学品过程中的重要步骤，不仅存在于非催化过程，也存在于催化过程。热解工艺有很多种，但其化学反应主体是自由基机理。针对文献在自由基机理这个宽泛概念下缺乏对自由基反应内涵的认识的现状，作者团队自2007年起开展了对煤、油页岩、重油、生物质等热解过程中的自由基行为研究，明确了文献中的一些不确切推论，形成了系统性认识，逐步建立了热解过程中的自由基化学体系。本文将介绍这些研究的主要进展，包括活性自由基与稳定自由基的确定、赋存状态及在热解过程中的作用、稳定自由基与缩聚反应和积炭的关系、催化剂积炭的形态与稳定自由基的关系、自由基诱导热解与反应调控等等。
Abstract：Pyrolysis occurs in both the thermal and catalytic conversion of heavy organic resources-such as coal, oil shale, heavy oil, biomass and waste organics-for fuel and chemical production. Pyrolysis generally involves two types of reactions, bond cleavage of a feed to generate free radical fragments and reaction of the radical fragments to yield products. The mechanisms involved, however, have not been addressed in most publications in the field and the previous studies have mainly focused on the yield and quality of products. Since 2007, researchers in the State Key Laboratory of Chemical Resource Engineering (SKLCRE) in Beijing University of Chemical Technology (BUCT) has studied the radical behaviors in, and mechanism of, the pyrolysis of many heavy organic resources, and have advanced our fundamental understanding of this area, key results include the experimental quantification of feed-structure dependent radical generation and the reactions of free radical fragments, establishment of the relationships between the active radicals and stable radicals (measurable by electron spin resonance, ESR), as well as the relationships between ESR radicals and coking in the reaction of volatiles both in the gas phase and on the catalyst surface, and numerical simulation of pyrolysis based on the radical mechanism. This article summarizes the major advancements reported in recent years by researchers in SKLCRE-BUCT and outlines the important topics for future study.