High-temperature resistant inorganic nanofiber membrane filtration coating material

A one-step, gas phase deposition method to create durable inorganic nanofiber coating on filtration substrates for enhanced filtration performance at high temperatures.
Technology No. 2019-353
IP Status: US Patent Pending; Application #: 63/189,970

Applications

  • High performance filter for high-temperature applications
  • Diesel Particulate Filters (DPF) and Gasoline Particulate Filters (GPF)

Key Benefits & Differentiators

  • Improved filtration performance: Compared to an uncoated commercial substrate (e.g. ceramic or metal fiber media), the nanofiber coating achieves higher porosity and higher efficiency (>99%) with improved particle loading and better efficiency-back pressure tradeoff.
  • Improved temperature resistance: The nanofiber membrane structure demonstrates the ability to withstand high temperatures (i.e. ≥600°C) over time with slight to no measurable changes to efficiency.
  • Simple processing: Low amounts of coating material are required, and post-processing enables versatility of coating onto already configured filter elements (e.g. filter cartridges and wall-flow filters).

Technology Overview

Diesel Particulate Filter (DPF) or Gasoline Particulate Filter (GPF) such as ceramic wall-flow monoliths are widely used in vehicle engine after-treatment applications to remove particulate matter. While advantageous, these filters cause undesired back pressure increase, which in turn affects vehicle fuel economy and power output adversely. Moreover, the performance of currently available filters are suboptimal. Efforts to improve filtration performance have been made by adding additional layers, such as ceramic powders or engine ash, on the base wall-flow substrate. Alternatively, nanofibers are known to have superior filtration performance over conventional micro-scale filtration materials; however, most nanofiber materials are polymer-based organic materials that cannot withstand high-temperatures environments.

Prof. David Y. H. Pui’s research group at the University of Minnesota has developed a gas phase deposition method to coat filtration substrates with an inorganic nanofiber filtration membrane that can withstand high temperatures. This one-step method uses trace amounts of starting material (or precursor) to generate highly porous (nano-scale) membranes on the base substrate material, yielding enhanced filtration performance across a range of applications. The simple deposition method is versatile in that it can be applied on most to all high temperature filtration materials (such as ceramic powder-based or metal fiber materials) and on already configured filter elements (such as filter cartridge and wall-flow filters).

Inorganic nanofiber-coated substrates demonstrate improved initial filtration efficiency over an order of magnitude and enhanced efficiency-back pressure tradeoff. Additionally, they achieve improved particle loading performance on ceramic powder-based substrates by reducing their deep-bed filtration regime. Improved filtration performance is maintained across a wide range of filtration velocity and at elevated temperatures (up to 1000°C). With this, the inorganic nanofiber coating can sustain exhaust temperature for DPF/GPF application while offering better efficiency-backpressure tradeoff than currently available wall-flow substrates. It can also be applied broadly toward gas and liquid filtration applications that necessitate high-temperature resistance.

Phase of Development

TRL: 4-5
Experimental characterization in lab/emulated environment. Full-scale prototype development and evaluation is underway.

Desired Partnerships

This technology is now available for:
  • License
  • Sponsored research
  • Co-development

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