Development of green corrosion inhibitors for absorption-based CO2 capture processes

腐蚀是使用链烷醇胺水溶液的二氧化碳（CO2）吸收过程中最严重的操作问题之一，尤其是当碳钢用于设备构造时。为了将这种严重的腐蚀抑制到可接受的水平，腐蚀抑制剂被广泛应用于该过程。然而，目前的腐蚀抑制剂是固有毒性的重金属，并且可能对人类健康和环境造成不利影响。由于关于化学品使用和处置的环境法规，此类有毒腐蚀抑制剂的处理和工艺废物的处置受到限制且成本高。现在必须发现环境可接受的新的腐蚀抑制剂，以提供工业替代品。因此，本研究的最终目标是开发具有成本效益的绿色缓蚀剂，并为有效应用所开发的绿色缓蚀剂建立最佳实践或策略。本论文的主要研究内容包括三个方面：1）潜在绿色缓蚀剂的理论筛选和配方设计; 2）缓蚀剂配方的性能评价; 3）绿色缓蚀剂体系的腐蚀预测和机理模型的建立。开发的绿色缓蚀剂以及有效缓蚀剂应用策略将随时可用，以响应环境法规和工业需求。这些抑制剂有望取代目前的重金属抑制剂，从而降低废物处理成本和健康风险。这将为加拿大在绿色化学品使用领域发挥领导作用提供一个机会。此外，从业者，特别是工艺工程师，将能够在其用于CO2捕集工艺的设计和操作的策略中考虑所开发的绿色腐蚀抑制剂，以降低工艺设备的能量消耗和溶液循环速率或尺寸。这将导致CO2捕集的资本和运营成本的显著节省，否则会受到腐蚀问题的限制。这将使二氧化碳捕获更加经济和环保。

Corrosion is one of the most severe operational problems in the carbon dioxide (CO2) absorption process using aqueous solutions of alkanolamines, especially when carbon steel is used for plant construction. To suppress such severe corrosion to an acceptable level, corrosion inhibitors are widely applied to this process. However, current corrosion inhibitors are heavy metals that are inherently toxic and potentially pose adverse impacts on human health and the environment. Due to the environmental regulations on the chemical use and disposal, handling of such toxic corrosion inhibitors and disposal of the process waste are restricted and costly. New corrosion inhibitors which are environmentally acceptable must now be discovered to provide alternatives to industry. The ultimate objectives of this proposed research are therefore to develop cost-effective green corrosion inhibitors and establish best practices or strategy for an effective application of the developed green corrosion inhibitors. The proposed research is divided into three main tasks: 1) theoretical screening and formulations of potential green corrosion inhibitors, 2) performance evaluation of the formulated inhibitors, and 3) development of a predictive and mechanistic corrosion model for the green inhibitor system. The developed green corrosion inhibitors together with the strategy for effective inhibitor application will be readily available in response to environmental regulations and industrial needs. These inhibitors are expected to replace current heavy metal inhibitors, thus reducing cost of waste disposal and health risk. This would present an opportunity for Canada to take a leadership role in the area of green chemical use. In addition, practitioners, especially process engineers, would be able to factor in the developed green corrosion inhibitors in their strategy for the design and operation of CO2 capture processes to reduce energy consumption and solution circulating rate or size of process equipment. This would lead to significant savings in both capital and operating costs for CO2 capture, which are otherwise limited by corrosion problems. This would make CO2 capture more economical and environmentally favorable.