Key advantages of OPXFLO technology include the extent of interaction with the gas particles, the large surface area and minimal pressure drop eg. compared to fluidised beds
How does the Potter cross-flow work?
The Potter Cross-Flow design distributes particles, either solid or liquid, over the length of a horizontal unit, or the height of a vertical unit in such a way as to ensure a high porosity (>99%) so that <1% of the volume in the processing region is occupied particles or droplets. An advantage of this design is that every particle/droplet in the processing region interacts with the gas. The contact area used for contacting is hence very large, and in comparison to other methods (such as a fluidised bed) the pressure drop is minimal in the horizontal (solid particle) configuration and lower in the vertical (solid or liquid droplet) arrangement.
horizontal system schematic
In a horizontal system as shown in Figure 1, particles fall from the roof of a square or rectangular channel and are blown along the channel by the gas, falling to the bottom of the channel where they are gathered and forwarded to the next curtain upstream or removed from the system. There is relative motion due to particles falling through the gas, and this promotes heat and/or mass transfer.
VERTICAL SYSTEM SCHEMATIC
In a vertical system, as shown in Figure 2, particles move from a vertical feeder unit in the centre to the wall as a result of the spinning gas-particle mixture. Thus the particles move radially through the gas while falling under gravity, both directions of travel contributing to the heat and/or mass transfer.
Another contributory factor to the high performance is the surface area available from the particles in flight. e.g. 500 kg/s of sand in flight for 3 seconds will produce a surface area in the processing region of 17300 square metres.