Gama Vitor, Dantas Beatriz, Sanyal Oishi, Lima Fernando V
Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, West Virginia 26506, United States.
ACS Eng Au. 2024 Mar 28;4(4):394-404. doi: 10.1021/acsengineeringau.3c00069. eCollection 2024 Aug 21.
Addressing climate change constitutes one of the major scientific challenges of this century, and it is widely acknowledged that anthropogenic CO emissions largely contribute to this issue. To achieve the "net-zero" target and keep the rise in global average temperature below 1.5 °C, negative emission technologies must be developed and deployed at a large scale. This study investigates the feasibility of using membranes as direct air capture (DAC) technology to extract CO from atmospheric air to produce low-purity CO. In this work, a two-stage hollow fiber membrane module process is designed and modeled using the AVEVA Process Simulation platform to produce a low-purity (≈5%) CO permeate stream. Such low-purity CO streams could have several possible applications such as algae growth, catalytic oxidation, and enhanced oil recovery. An operability analysis is performed by mapping a feasible range of input parameters, which include membrane surface area and membrane performance metrics, to an output set, which consists of CO purity, recovery, and net energy consumption. The base case for this simulation study is generated considering a facilitated transport membrane with high CO/N separation performance (CO permeance = 2100 GPU and CO/N selectivity = 1100), when tested under DAC conditions. With a constant membrane area, both membranes' intrinsic performances are found to have a considerable impact on the purity, recovery, and energy consumption. The area of the first module plays a dominant role in determining the recovery, purity, and energy demands, and in fact, increasing the area of the second membrane has a negative impact on the overall energy consumption, without improving the overall purities. The CO capture capacity of DAC units is important for implementation and scale-up. In this context, the performed analysis showed that the m-DAC process could be appropriate as a small-capacity system (0.1-1 Mt/year of air), with reasonable recoveries and overall purity. Finally, a preliminary CO emissions analysis is carried out for the membrane-based DAC process, which leads to the conclusion that the overall energy grid must be powered by renewable sources for the technology to qualify within the negative emissions category.
应对气候变化是本世纪的主要科学挑战之一，人们普遍认为人为碳排放是这一问题的主要原因。为了实现“净零”目标并将全球平均气温上升控制在1.5摄氏度以内，必须大规模开发和部署负排放技术。本研究探讨了使用膜作为直接空气捕获（DAC）技术从大气中提取二氧化碳以生产低纯度一氧化碳的可行性。在这项工作中，使用AVEVA过程模拟平台设计并模拟了一个两级中空纤维膜组件工艺，以生产低纯度（约5%）的一氧化碳渗透物流。这种低纯度一氧化碳物流可能有多种应用，如藻类生长、催化氧化和强化采油。通过将包括膜表面积和膜性能指标在内的可行输入参数范围映射到由一氧化碳纯度、回收率和净能耗组成的输出集来进行可操作性分析。本模拟研究的基准案例是在DAC条件下测试时，考虑具有高CO/N2分离性能（CO渗透率=2100 GPU，CO/N2选择性=1100）的促进传输膜生成的。在膜面积恒定的情况下，发现两种膜的固有性能对纯度、回收率和能耗都有相当大的影响。第一个模块的面积在决定回收率、纯度和能量需求方面起主导作用，事实上，增加第二个膜的面积会对总能耗产生负面影响，而不会提高整体纯度。DAC装置的二氧化碳捕获能力对于实施和扩大规模很重要。在此背景下，所进行的分析表明，m-DAC工艺作为一个小容量系统（每年处理0.1-1百万吨空气）可能是合适的，具有合理的回收率和整体纯度。最后，对基于膜的DAC工艺进行了初步的碳排放分析，得出的结论是，该技术要符合负排放类别，整个能源电网必须由可再生能源供电。
