Polystyrene depolymerization: Scavenging brominated flame retardants

聚苯乙烯是一种用途广泛的聚合物，大规模生产并应用于许多消费品，包括包装。不可生物降解的聚合物，如聚苯乙烯，是一种环境负担；膨胀聚苯乙烯是城市固体中最棘手的成分之一。该行业现在正试图从废弃聚合物和报废聚合物中获得价值。由于材料成本低于石油原料成本，这种驱动减少了浪费，具有良好的经济效益。热裂解和热解是几种回收有价值单体的技术之一，这些单体是聚合物的组成部分。在这些过程中，聚合物被加热到超过400摄氏度甚至超过600摄氏度的温度，聚合物分解成苯乙烯（单体）和碳氢化合物（例如苯）。报废的聚苯乙烯含有热稳定剂、溴化阻燃剂、过氧化苯甲酰、三氧化二锑等。溴化化合物伴随聚苯乙烯消费品提供防火性能，以满足UL或CSA防火要求。然而，这些化合物中的许多现在都被禁止了。拉弗妮集团是加拿大一家回收聚合物的大公司，但他们必须去除违禁化合物。我们将共同开发清除溴化化合物的技术，以满足联邦要求。去除这些化合物减少了聚苯乙烯对城市垃圾填埋场的负担，但由于他们有一个可行的业务运营，将为他们的客户保持原料供应。我们将首先在热重分析仪中测量聚苯乙烯的热性能。这些数据将确定进行反应器试验以清除溴化合物的温度范围。下一步，我们将在流化床反应器中加热聚苯乙烯，并监测气体产物的组成。我们还将在高效液相色谱分析仪中冷凝气体并分析水相。我们的GC-MS分析仪将识别有机相的化合物。第三步将确定吸收剂，我们可以直接添加到流化床中以清除溴化化合物或添加后处理步骤来捕获它们。

Polystyrene is a versatile polymer that is produced at enormous scale and applied in many consumer productsincluding packaging. Nonbiodegradable polymers, like polystyrene, represent an environmental burden;expanded polystyrene is among the most intractable components in municipal solid. The industry is now tryingto derive value from waste polymer and end-of life polymer for a feedstock. This drive reduces waste and hasan economic benefit because the material costs are lower than the costs of the petroleum feedstock. Thermalcracking and pyrolysis are among the several technologies to recover valuable monomers-the building blocksof polymers. In these processes, the polymer is heated to temperatures exceeding 400 oC and even beyond 600oC and the polymer decomposes to styrene (monomer) and hydrocarbons (benzene, for example).End-of-life polystyrene contains thermal stabilizers, brominated fire retardants, benzoyl peroxide, antimonytrioxide, among others. Brominated compounds accompany polystyrene consumer products to provide fireproof properties to meet UL or CSA fire resistance requirement. However, many of these compounds are nowbanned. Lavergne Group is a major Canadian company that recycles polymers but they must remove thebanned compounds. Together we will develop technology to scavenge the brominated compounds to meetfederal requirements. Removing these compounds reduces the burden of polystyrene to municipal landfills butwill maintain their supply of feedstock for their customers as they have a viable business operational.We will first measure the thermal properties of the polystyrene in a thermogravimetric analyser. This data willidentify the temperature range to conduct reactor tests to scavenge the bromine compounds. In the next step, wewill heat the polystyrene in a fluidized bed reactor and monitor the gas product composition. We will alsocondense the gases and analyse the aqueous phase in an HPLC analyser. Our GC-MS analyser will identify thecompounds of the organic phase. The third step will identify absorbents that we can add directly into thefluidized bed to scavenge the brominated compounds or to add a post-treatment step to capture them.