Fundamental Understandings of the Causes and Consequences of Chemical, Electrical and Thermal Heterogeneities in Aluminium Electrolysis Cells

原铝生产行业正在不断努力提高生产率，降低成本，降低单位能耗。然而，工艺的稳定性对电解槽内的局部变化越来越敏感。这些变化可以是化学的(氧化铝分布)、热的(能级)或电的(电流分布)。这种不平衡会导致正常工艺条件的变化，导致电池的负面后果，如生产率降低、能源消耗增加、污泥形成或过度产生温室气体。本提案中描述的研究方案旨在增强和开发用于数值工具的新模块，该模块将允许模拟单元中的异质条件及其潜在后果。关于该数学模型的最初工作是由申请人在以前的研究中进行的。该模型允许模拟电池中的化学和电学变化，而不考虑热机制。有了这些信息，数学模型就有能力预测电解过程中全氟碳排放的开始。很好地使用这个工具，并进一步完善，可以为行业的多个问题提供解决方案。有许多因素在细胞异质性中起着重要作用，但数学模型中尚未考虑这些因素。制定研究计划的目的是逐步在模型中引入这些元素，并实现更准确的预测和精确的解决方案，以解决工业单元的真实条件。该计划的初始阶段(在本提案中详细描述)将以电池中发生的热交换为目标，并将能量平衡与现有的化学和电气模块相结合。进一步的改进，超出本提案的范围，将随后调查运行事件对电池异质性的化学、热和电影响。第三阶段将考虑添加剂的影响和更高级的主题，如阳极事件和氧化铝金属垫和电解槽之间的交换机制。未来五年考虑的研究方案计划包括组建一名博士生，将能量平衡整合到数学模型中，并使用指标来评估观察到的失衡的严重程度。硕士研究生也被认为是研究低电压和高电压阳极效应的热后果。在这两种情况下，执行的工作都将基于实验室设置中的理论概念和实验验证。最后，一名博士后研究员将进行广泛的参数研究，以查明失衡的主要原因，并为加拿大铝生产商提出潜在和现实的解决方案。

The primary aluminium production industry is continuously trying to increase their production rate, with a reduction of their cost along with lower specific energy consumption. However, the stability of the process is becoming more and more sensitive to local variations within an electrolysis cell. These variations may be chemical (alumina distribution), thermal (energy level) or electrical (current distribution). Such imbalance lead to variations of the normal process conditions leading to negative consequences for the cell such as lower production rate, increase of energy consumption, sludge formation, or excessive production of greenhouse gases. The research program described in this proposal aims at enhancing and developing new modules for a numerical tool that would allow simulations of the heterogenous conditions in a cell and their potential consequences. The initial work on that mathematical model was performed by the applicant in previous research. The model allows the simulation of chemical and electrical variations in the cell, without any considerations for the thermal mechanisms. With this information's, the mathematical model has the ability to predict the onset of perfluorocarbon emissions during the electrolysis process. A good usage of this tool, with further refinements can provide solutions for multiple issues of the industry. There are numerous factors that play a major role in the cell heterogeneity that are not considered yet in the mathematical model. The research plan is developed with the vision to progressively introduce these elements in the model and reach more accurate prediction and pinpoint more detailed solutions to address the real conditions of industrial cells. The initial phase of the program (described in detail in this proposal) will target the thermal exchange occurring in the cell and couple the energy balance with the existing chemical and electrical modules. Further improvement, beyond the scope of this proposal will subsequently investigate the chemical, thermal and, electrical impact of operational events on the heterogeneity of the cell. A third phase will consider the impact of additives and more advanced themes such as anodic incidents and exchange mechanisms between the alumina metal pad and the electrolysis bath. The research program plan considered for the next five years includes the formation of a PhD student to integrate an energy balance into the mathematical model with indicators that can allow the evaluation of the level of severity of the imbalance observed. A master student is also considered to investigate the thermal consequences of low- and high-voltage anode effects. In both cases, the work performed will be based on theoretical concepts and experimental validation in a laboratory setup. Finally, a postdoctoral fellow will perform an extensive parametric study to pinpoint the main cause of the imbalance and propose potential and realistic solution for Canadian aluminium producers.