Liquid Displacement

Method and Arrangement for Determining at Least One Pore-Related Parameter of a Porous Structure

Synopsis

Evapoporometry (EP) assesses porosity, pore size, pore-size distribution (PSD), and internal fouling in various membrane types (flat-sheet, hollow fibre, tubular). It measures evaporative mass loss from pre-saturated membranes using a wetting volatile liquid.


Opportunity

The market for Liquid Displacement Porometers (LDP) is substantial—with an estimated 10,000 units currently in use worldwide. Each LDP costs approximately S$100,000, indicating a market potential of around S$1 billion. A high-resolution EP instrument, capturing just 10% of this market, could be worth a significant S$100 million.

 

Technology

This technology involves an apparatus and method for determining the porosity, pore size, PSD and internal pore fouling across all membrane types, including flat-sheet, hollow fibre and tubular membranes (including lumen side or outer wall). EP measures the evaporative mass loss from membranes pre-saturated with a wetting volatile liquid. The vapour pressure of the liquid is reduced due to surface curvature at the air-liquid interface within the pores, enabling accurate PSD measurement.

 

Figure 1: Apparatus and method for determining various parameters of a porous structure.

Figure 1: Apparatus and method for determining various parameters of a porous structure.

 

Applications & Advantages

  • Straightforward analysis protocol based on evaporation at ambient conditions
  • Wider pore size range from 5 – 360 nm
  • High degree of accuracy
  • No calibration needed
  • Cost-effective instrument—35% less expensive than LDP

 

NTU Technology: Evapoporometry (EP) Competitor: Liquid Displacement Porometry (LDP) 
Operating Pressure Ambient As high as 35 bar 
Potential membrane damage No Yes 
Use for membrane autopsies Yes No 
Smallest pore measurable 4 nm 14 nm 
Characterise hollow fibre with internal active layer Yes No 

Inventor

Prof CHEW Jia Wei