ALD (atomic layer deposition)-enabled high performance membranes for gas separation

Background

The separation of gas mixtures, particularly the purification of hydrogen from components like carbon monoxide, carbon dioxide, and light hydrocarbons, is critical for natural gas and biogas processing, as well as for hydrogen production from chemical processes or fossil fuels.

Current industrial methods, such as pressure swing absorption and cryogenic processes, are often expensive and yield hydrogen of insufficient purity. While membrane separation technology offers a promising alternative for more efficient and cost-effective purification, existing H2-selective membranes face challenges. Many are not optimized for the high temperatures required in processes like steam-methane reforming, where syngas cooling would add significant cost. Furthermore, a common hurdle in membrane development is the inherent trade-off between achieving high gas permeability and maintaining excellent selectivity for the desired component, which limits their overall performance and efficiency.

Technology

Researchers at Stony Brook University have developed a technology that modifies polybenzimidazole (PBI) membranes to enhance membrane hydrogen permeability and H2/CO2 selectivity.

One approach involves nanoengineering PBI using a few-cycle Atomic Layer Deposition (ALD). This process disrupts chain packaging, which reduces free volume and enhances gas diffusion and size-sieving capabilities. The membranes show high H2 permeability and high H2/CO2 selectivity, providing a low-cost and energy-efficient means for the hydrogen separation and CO2 capture. Additionally, these membranes can operate at the syngas processing temperature (150°C).

Advantages

• Enhanced H₂ Permeability and Selectivity
• High-Temperature Stability
• Cost Efficiency

Application

• Hydrogen Production and Purification
• Industrial Hydrogen Recovery
• Fuel Gas Upgrading and Carbon Dioxide Removal