减压渣油与废塑料共热解行为的热失重法分析

Studies on co-processing vacuum residue with waste plastics using thermogravimetric analysis

为了给减压渣油（VR）与废塑料在延迟焦化中的共焦化工艺开发提供借鉴，采用热失重分析法，在氮气气氛下，对VR、低密度聚乙烯（LDPE）、高密度聚乙烯（HDPE）、聚丙烯（PP）、聚苯乙烯（PS）4种废塑料单独热解时及其共热解时的热失重行为进行了研究，并对热解机理进行了探讨。结果表明：这4种塑料单独热解时的快速热解失重温区与VR的重叠，在热失重率为80％时的对应温度均在300～500℃内；共热解时，不同塑料对VR热失重行为的影响不同，其中HDPE和LDPE均可引起VR的最大热失重速率值增大，协同效应较强，而PS，PP与VR的协同效应较小；这4种塑料的热分解反应都可用一级反应动力学来描述，而VR的单独热解以及其与PP的共热解反应则适用于分段的2个一级动力学模型。

To give some reference on co - processing of vacuum residue （VR） and waste plastics in delayed coking unit,the pyrolysis behaviors of single VR, such plastics as Low density polyethylene （ LDPE）, high density polyethylene （ HDPE ）, poly-propylene （ PP）, polystyrene （PS） and their mixtures with different ratios were studied by using thermogravimetric analyzer. Also the mechanism of pyrolysis of VR and plastics was discussed. The results showed that there was a same temperature range of pyrolysis （ 300 - 500 ℃ ） , where such 4 kinds of plastics and VR had the weight loss ratio of 80% respectively. Such 4 plastics have different influence on the co - pyrolysis of VR with plastics, and there was a more obvious synergetic reaction between VR and LDPE or HDPE, compared with copyrolysis of VR and PS or PP. The pyrolysis of VR and plastics accorded with the model of the first order reaction respectively, while the pyrolysis of PP and VR was well fitted with two independent first -order kinetic models in two temperature regions. There was a superposition in temperature range between the pyrolysis of 4 plastics and the reaction of VR in delayed coking process, and the interaction of VR with LDPE or HDPE was more obvious in co -pyrolysis.