Enabling production of sustainable chemicals by understanding microwave reactor engineering hydrodynamics

化学过程的电气化是旨在减少加拿大各行业碳足迹的能源过渡的一部分。传统上大量消耗化石能源的化学工业，有必要调整其流程，让电力的使用占据更大的主导地位。微波反应利用电能促进化学反应，在实验室规模上显示出巨大的潜力，可以提高化学反应的产量、质量和能源效率。在过去的10年里，加拿大技术公司PyroWave在工业层面部署微波技术方面取得了突破性进展。他们开发了一种催化微波解聚反应器，可以有效地裂解聚苯乙烯，生成可用于合成初级品聚苯乙烯的苯乙烯单体。考虑到只有30%的加拿大社区可以使用聚苯乙烯回收设施，而且热波工艺可以有效地处理受污染的聚苯乙烯，这项具有成本效益和高产的技术将极大地减少加拿大产生的塑料垃圾量。目前，热浪反应堆在运行和优化方面面临着一些问题。其中一些问题与微波的影响有关，微波会产生有利于热解的局部高温部位，但必须加以控制，以确保反应器的足够产量和结构完整性。这需要深入了解反应堆在受到微波辐射时的多相流。该项目将多相计算流体力学(CFD-DEM)和实验工作相结合，以了解、量化和预测微波辐射对反应堆内固液两相流动和换热的影响。该项目将使用热波微波辅助热解反应器作为模型系统，因为该反应器存在工业规模。我们相信，该项目的成果将使设计新的催化微波解聚反应器成为明天循环经济的关键贡献者。

Electrification of chemical processes is part of the energy transition that aims at reducing the carbon footprint of various industries in Canada. There is a need for the chemical industry, traditionally a heavy consumer of fossil energy, to adapt its processes and give a more dominant place to the use of electricity. Microwave reactions, using electricity to promote chemical reactions, have shown tremendous potential at the laboratory scale to improve product yield, quality and the energy efficiency of chemical reactors. Over the last 10 years, breakthrough advances have been made towards the deployment of microwave technology at industrial level by the Canadian technology company Pyrowave. They have developed a catalytic microwave depolymerization reactor which can effectively pyrolyze polystyrene to produce styrene monomers which can be used to synthetize virgin-grade polystyrene. Considering that only 30% of Canadian communities have access to polystyrene recycling facilities and that the Pyrowave process can work efficiently with contaminated polystyrene, this cost-effective and high-yield technology would tremendously reduce the amount of plastic waste generated in Canada. Pyrowave currently faces issues in the operation and optimization of their reactor. A number of these issues are related to the impact of the microwaves, which generate local high-temperature sites which are beneficial to the pyrolysis, but which must be controlled to ensure adequate yield and structural integrity of the reactor. This requires in-depth understanding of the multiphase flows within the reactor when it is subject to microwave radiation. The proposed project combines multiphase computational fluid dynamics (CFD-DEM) and experimental work to understand, quantify and predict the influence of microwave radiation on the solid-fluid flow patterns and heat transfer within the reactor. The project will use the microwave-assisted pyrolysis reactor of Pyrowave as model system since this reactor exists at an industrial scale. We believe that the outcomes of this project will enable the design of new catalytic microwave depolymerization reactors which will be a key contributor to the circular economy of tomorrow.