ИСТИНА

Создание композитных мембран на основе палладиевых сплавов и анодного оксида алюминия для извлечения и очистки водорода из газовых смесей сложного состава

Hydrogen is an important part of the global economy and already accounts for a significant segment of the energy sector. The rapidly growing use of hydrogen is driven by its high energy density, light weight, availability, and environmental friendliness. Thanks to the above advantages, there is a significant growth in the global market for the production and use of hydrogen, which, according to experts, should grow almost 2 times over the next 10 years. Currently, membrane technologies are one of the most cost-effective methods for hydrogen extraction and purification. Compared to distillation methods and short-cycle adsorption, the use of membranes is more energy efficient and potentially allows the production of high-purity hydrogen. Today, dense metal membranes made of palladium metal have record selectivity and allow operation at high temperatures. The disadvantage of palladium is its rather low mechanical stability, embrittlement (most pronounced at operating temperatures below 300 °C), and low resistance to poison gases. This project aims to develop composite membranes based on palladium alloys and anodic aluminum oxide (AAO) for hydrogen purification and extraction from gas mixtures. Porous AAO acts as a mechanical support, whereas selectivity is achieved by a dense active layer based on palladium alloys on the AAO surface. The additional incorporation of the alloy into the AAO pores is intended to improve the long-term stability of the membranes by increasing the adhesion of a dense metal layer and increasing the gas impermeability. The proposed design of hydrogen membranes allows the thickness of the dense active Pd-based layer to be reduced to below microns, which will lead to an increase in permeability while maintaining high selectivity. The use of Pd-Ag and Pd-Cu alloys instead of pure Pd is necessary for long-term resistance to poison gases and to reduce the negative effects of hydrogen at low operating temperatures. To achieve this project goal, a number of interrelated tasks will be solved: (1) numerical modeling of hydrogen transport through a composite membrane; (2) formation of a AAO-based mechanical support with specified parameters of the porous structure; (3) optimization of the conditions for the formation of a dense metal film on the AAO surface, as well as of nanowires in AAO channels with a given composition, microstructure, and geometric parameters; (4) study of the permeability and selectivity of the developed membrane for hydrogen during its extraction from mixtures with inert gases; (5) analysis membrane’s resistance to degradation over a wide range of operating temperatures and exposure to poison gases. The main result of the project will be a hydrogen membrane prototype with known permeability and selectivity, optimized composition and microstructure of the active layer, and improved resistance to poison gases and operation in a wide temperature range.

1. Методика расчета потока водорода через композитную мембрану от состава активного слоя, пористости анодного оксида алюминия (АОА), толщины незаполненной и заполненной части АОА и сплошной плёнки сплава, а также парциального давления водорода. 2. Зависимости состава, микроструктуры и толщины сплошного палладий-содержащего слоя на поверхности АОА от условий термического и/или магнетронного напыления (на примере сплавов Pd-Ag и Pd-Cu). 3. Зависимости состава и микроструктуры палладиевых сплавов от условий электрохимического осаждения (состав электролита, потенциал осаждения) на гладкую подложку и в каналы АОА (на примере сплавов Pd-Ag и Pd-Cu). 4. Экспериментальные образцы композитных мембран со сплошным активным слоем на основе сплавов Pd-Cu и Pd-Ag с различным составом, толщиной сплошного слоя на поверхности АОА и длиной нанонитей в каналах АОА. 5. Зависимость селективности водородных композитных мембран при выделении водорода из смесей с инертными газами в зависимости от параметров структуры АОА (диаметр пор/пористость и толщина), состава и микроструктуры активного слоя, толщины незаполненной и заполненной части АОА и сплошной плёнки металла. 6. Результаты аттестации деградационной устойчивости (сохранения проницаемости и селективности по водороду) мембран к действию отравляющих веществ и работе в широком диапазоне температур в зависимости от состава, микроструктуры и геометрических параметров активного слоя.