Multiscale Process Intensification of Waste Valorization Reactions

我的研究项目的中心主题是开发强化和可持续的化学过程，用于金属的回收，二氧化碳的封存，以及利用工业，城市和农业废料生产有价值的无机材料。处理固体废物-流体反应时面临的一个挑战是，固体-液体、固体-气体和气体-液体界面的传质限制以及不利的热力学导致反应速率缓慢、反应转化不完全、能量消耗和处理成本高、产品性能不佳。克服浆料反应限制的传统方法是调整工艺变量，如温度、压力、粒度、混合速率和试剂浓度。这些宏观方法可能是有效的，然而，它们是以环境为代价的：能源和原材料的高消耗，大量残留物的产生以及污染物和温室气体的排放。在低品位和废物资源的处理或增值方面，这种传统方法在工业规模上往往是不可行的。因此，需要可持续的解决方案。该DG计划的目的是通过探索和开发在不同空间和时间尺度上起作用的过程强化策略，克服与环境相关的浆体反应的反应速率限制。长期目标是确定三类固体废物的价值：(a)金伯利岩和蛇纹石（矿物加工）；(b)黑色/红色酒类（纸浆和纸张）；(c)水果/蔬菜渣（水果加工）。短期研究集中在三个方面：(1)反应与反应器设计；(2)反应分离；(3)溶剂力学。针对这些领域，研究了五种多尺度强化方法：(1)将机械搅拌间歇反应转化为声波塞流连续反应；（ii）开发用于特定废物转化反应的新型催化矿物；（iii）用超疏水分子功能化惰性固体介质；（iv）使用不混相有机相和金属-有机骨架（MOF）化合物进行反应萃取；(5)用绿色溶剂代替水性反应介质，用于反应吸收和溶剂化学。最终，这项研究计划的目的是鼓励在工业和研究界采用工艺强化技术来取代传统工艺，并促进化学、冶金和矿产工业（加拿大的经济驱动力）所需的可持续工艺的发展，以减少其对环境的影响和碳排放。此外，所开发的多尺度过程强化方法也可推广到其他工业、城市和农业过程，从而降低能源强度、碳强度和环境足迹。

The central theme of my research program is the development of intensified and sustainable chemical processes for the recovery of metals, the sequestration of CO2, and the production of valuable inorganic materials, using wastes of industrial, urban and agricultural origins. A challenge when working with solid waste-fluid reactions is that mass transfer limitations across solid-liquid, solid-gas and gas-liquid interfaces and unfavorable thermodynamics lead to slow reaction rates, incomplete reaction conversions, high energy expenditure and processing costs, and inadequate product properties. The traditional approach to overcoming slurry reaction limitations is to adjust process variables, such as temperature, pressure, particle size, mixing rate, and concentration of reagents. These macro-scale approaches can be effective, however, they come at a cost to the environment: high consumption of energy and raw materials, vast generation of residues, and emissions of pollutants and greenhouse gases. In the treatment or valorization of low-grade and waste resources, such conventional approaches are often unfeasible at the industrial scale. Sustainable solutions are thus needed. The aim of this DG program is to overcome reaction rate limitations of slurry reactions of environmental relevance, by exploring and developing process intensification strategies that act over different scales of space and time. The long-term objective is to valorize three classes of solid wastes: (a) kimberlite and serpentine (mineral processing); (b) black/red liquors (pulp and paper); (c) fruit/vegetable pomace (fruit processing). The short-term research is clustered in three areas: (1) reaction and reactor design; (2) reactive separations; and (3) solvomechanochemistry. For these areas, five multiscale intensification approaches are investigated: (i) converting mechanically stirred batch reactions into sonicated plug flow continuous reactions; (ii) developing novel catalytic minerals for specific waste conversion reactions; (iii) functionalizing inert solid media with superhydrophobic molecules; (iv) using immiscible organic phases and metal-organic framework (MOF) compounds for reactive extraction; and (v) replacing aqueous reaction media with green solvents for reactive absorption and solvomechanochemistry. Ultimately, the purpose of this research program is to encourage the adoption of process intensification technologies in place of conventional processes, in industry and among the research community, and to catalyze the development of the types of sustainable processes required by the chemical, metallurgical and minerals industries (Canada's economic drivers) to reduce their environmental impact and carbon emissions. Moreover, the multiscale process intensification approaches developed may also be extended to other industrial, urban and agricultural processes where reduction of energy intensity, carbon intensity and environmental footprint could be achieved.