EAGER: Nitrogen-Selective Membrane for Carbon Capture with Simultaneous Ammonia Synthesis

摘要#1249494 Wilcox，美国斯坦福大学斯坦福大学的Jennifer Wilcox教授首次尝试合成和测试从气体混合物中选择性分离N2的膜，该奖项代表了这一尝试的延续。这种新颖的交叉技术将在工业规模上有许多应用，包括从烟道气中捕获CO2，天然气净化，空气分离和氨合成。在所提出的工作中，提出了由钌和地球丰富的V族金属（例如钒和铌）的合金制成的金属膜用于催化选择性N2分离。这项工作包括电子结构理论计算的理论建模和使用高温实验室规模的膜反应器的实验测试。包括理论和实验将允许设计具有针对给定应用的最佳选择性和渗透性的金属膜材料。这项工作的建模组件的力量是，许多合金可以筛选，只有最有前途的候选人合成和测试。Wilcox的计算预测，含Ru的合金将增加通过膜的传输。去年，EAGER奖授予了这项潜在的令人兴奋的实验。设计并建造了一个实验室规模的高温膜反应器，以研究由Nb和V金属及其与Ru的不同成分合金组成的膜箔的N2渗透性和选择性。PI已经能够使用由供应商（Goodfellow）提供的40 m厚的纯V和Nb膜箔测量N2通量和渗透率。然而，存在与VRu和NbRu合金的材料合成相关的重大挑战，尽管bcc相的热力学稳定性高达40 at. %的Ru。两个不同的供应商，即艾姆斯实验室的材料制备中心和Goodfellow被要求合成不同组成的RuV和RuNb合金。尽管他们做出了努力，但由于合金的脆性，他们都无法将不同成分的合金制造成微米厚的箔。这妨碍了对该项目的核心进行评价。PI将与西南研究所的肯特库尔特博士合作，在多孔Hastelloy X支架上溅射含Ru的V/Nb存款合金。该EAGER提案允许进行制造并获取初步数据，以完成概念验证。拟议工作的结果将产生许多更广泛的影响。通过设计成本效益高的膜技术减少燃煤发电厂等点源的二氧化碳排放量，将减少排放到大气中的二氧化碳。除了碳捕获，这项技术还可以提供一种在大气压下进行氨合成过程的途径，为农业产业节省大量资金。全球近一半的氢气用于氨合成，主要用于农业，这一需求与世界人口增长成正比。肥料是确保全球粮食产量充足的最重要因素之一。通过选择性N2膜技术的应用，氨可以以比传统高压哈伯-博世工艺更低的能源成本生产，并且氨可以直接用于促进农业工业。

ABSTRACT#1249494Wilcox, JenniferTechnical ImpactsThis award represents a continuation of the first attempts to synthesize and test membranes that selectively separate N2 from gas mixtures by Professor Jennifer Wilcox at Stanford University. This novel, crosscutting technology will have numerous applications at the industrial scale, including CO2 capture from flue gas, natural gas purification, air separation, and ammonia synthesis. In the proposed work, metallic membranes made from alloys of ruthenium and earth-abundant Group V metals, such as vanadium and niobium, are proposed for catalytic selective N2 separation. The effort includes both theoretical modeling with electronic structure theory calculations and experimental testing using a high-temperature benchscale membrane reactor. Including both theory and experiment will allow for the design of a metallic membrane material with optimal selectivity and permeability for a given application. The strength of the modeling component to this work is that many alloys can be screened with only the most promising candidates synthesized and tested. The computations by Wilcox predict the alloys with Ru will allow for an increase in transport through the membrane.An EAGER award was made last year to carry out this potentially exciting experimentation. A bench-scale high-temperature membrane reactor was designed and built to investigate N2 permeabilities and selectivities of membrane foils comprised of Nb and V metals and their varying-composition alloys with Ru. The PI has been able to measure N2 flux and permeance using 40 m-thick membrane foils of pure V and Nb supplied by a vendor (Goodfellow). However, there have been significant challenges associated with material synthesis of the VRu and NbRu alloys, despite the thermodynamic stability of the bcc phase up to 40 at. % Ru in each of these alloys. Two different vendors, i.e.,the Materials Preparation Center at Ames Laboratory and Goodfellow, were asked to synthesize RuV and RuNb alloys at varying compositions. Despite their efforts, neither was able to fabricate alloys of varying compositions into micron-thick foils due to the brittleness of the alloys. This prevented the evaluations at the heart of the Project from being made. An alternative vendor and fabrication methodology has been found. The PI will be working with Dr. Kent Coulter of Southwest Research Institute to sputter deposit alloys of V/Nb with Ru on porous Hastelloy X supports. This EAGER proposal allows for the fabrications to be conducted and the preliminary data to be taken to allow completion of the proof of concept. Broader Impacts Broader impacts of the results of the proposed work are many. Carbon dioxide abatement from point sources such as coal-fired power plants through the design of cost-effective membrane technology will result in a decrease of CO2 emitted into the atmosphere. In addition to carboncapture, this technology may provide a route to carry out the ammonia synthesis process at atmospheric pressures, adding huge savings to the agricultural industry. Nearly half of the hydrogen produced globally is used for ammonia synthesis, which is primarily used for agriculture, a demand that is directly proportional to world population increase. Fertilizers are one of the most important factors in securing sufficient global food production. Through the application of selective-N2 membrane technology, ammonia could be produced at a lower energy cost than the traditional high-pressure Haber-Bosch process and the ammonia can be used directly to advance the agriculture industry.