Combined mass-transfer and energy-flux studies for Absorption-based CO2 capture process

从工业烟气中捕获二氧化碳(CO2)一直被认为是加拿大和世界各国减缓温室气体排放的关键战略之一。目前，将气体吸收到烷醇胺水溶液中是最可靠的缓解技术，不存在捕获二氧化碳的技术风险。然而，目前的商业技术仍然伴随着高昂的资本和运营成本。可以通过提高所用烷醇胺的吸收和再生性能，以及通过改进塔设计或工艺配置来降低二氧化碳捕获成本。使用高能效的烷醇胺可显著减少该过程的能源需求，从而降低运营成本。然而，这导致了整个捕获过程的资本成本增加。因此，如果要降低总体捕集成本，吸收柱和再生柱的性能也必须得到改善。这项研究的目的是：1)确定在CO2吸收和溶剂再生条件下，装有规整填料和喷嘴的各种塔的传质性能和流体力学行为；2)测量参与CO2吸收和再生现象的能量通量组分；3)建立一个基于速率的理论模型，综合塔的传质性能、能量通量组分和流体力学行为；4)进行优化研究，以得出用于CO2捕集应用的塔内部件的优化设计。这项研究很重要，因为它不仅将大大节省资本支出，而且还将显著节省二氧化碳捕获的运营成本。研究成果将为加拿大提供一个及时减少二氧化碳排放的大好机会，而不会给不断增长的经济带来负担。

Capturing carbon dioxide (CO2) from industrial flue gas streams has been considered as one of the key strategies for mitigation of greenhouse gas emissions in Canada and the world. At present, gas absorption into an aqueous alkanolamine solution is the most reliable mitigation technique that bears no technical risk for CO2 capture. However, the current commercial technology is yet associated with high capital and operating cost. The CO2 capture cost can be reduced by enhancing absorption & regeneration performance of alkanolamines used and also by improving column design or configuration of the process. Use of energy-efficient alkanolamines could result in a significant reduction in energy requirement for the process, thereby reducing operating cost. It however leads to an increase in capital cost of the entire capture process. Therefore, it is important that performance of absorption and regeneration columns must also be improved if the overall capture cost is to be reduced. The objectives of this proposed research are: 1) to determine mass-transfer performance and hydrodynamic behavior of various columns fitted with structured packings and also spray nozzles under CO2 absorption and solvent regeneration conditions, 2) to measure energy-flux components taking part in CO2 absorption and regeneration phenomena, 3) to develop a theoretical rate-based model that integrates mass-transfer performance, energy-flux components and hydrodynamic behavior of the columns, and 4) to perform an optimization study to arrive at the optimal design of column internals for CO2 capture application. This research is important because it will lead to significant savings in not only the capital expenditure but also the operating cost of CO2 capture. The research outcomes will present Canada with a great opportunity for reducing its CO2 emissions in a timely manner without posing a burden on the growing economy.