Improved Fluidized Bed Precipitator

Reference Number: K 07-15

Inventors: Becker, Gina; Diaz, Sigifredo; Hanson, Michael

Owner: Kansas State University Research Foundation

USPTO Link:

Invention Summary

Though liquid-solid, gas-solid, or gas-liquid-solid fluidized bed technologies are not new, traditional systems have a drawback that limits economy:  above critical flow rates, solid particles will be carried out of the system with the fluid and be lost.  The critical flow rate, therefore, limits the amount of material that can be processed in a given size system.   Secondary recovery systems can be used to collect and return the lost solids, but these are expensive in terms of both capital and operational expenses.

The current technology includes sloped settling surfaces at the exit of the system, which reduce the vertical velocity of the exiting fluid.  This allows particles to be retained in the system at higher flow rates, providing the benefit of smaller equipment to process any given flow rate of material.
 
One configuration of the technology provides particular benefits in applications that require a gaseous injection into a liquid-solid bed, which can cause turbulence that causes particles to be lost.   By configuring the settling surfaces so that gas can escape via a different path than the liquid, gases can be used to provide additives and/or mixing without disturbing the solids-settling capabilities.

This technology was developed to precipitate soluble phosphorous as struvite (magnesium ammonium phosphate) for wastewater treatment applications.  However, the inventors see opportunities for this technology in any application that currently employs solid-liquid, liquid-solid, gas-solid, or gas-liquid-solid fluidized beds.

Advantages

  • Breaks typical tradeoff limit between high flow rates and good solid retainment
    • Allows for faster flow rates in a given size of equipment
    • Allows for smaller equipment for a given flow rate
  • Allows for turbulence in the bed (for good mixing) without sacrificing solid retainment
  • Allows for injection of gaseous additives without sacrificing solid retainment
  • Allows for use of gas bubbles for mixing without sacrificing solid retainment

Applications

  • Recovering phosphorous from waste streams of ethanol plants, food industries, and any other industry waste streams
  • Zeolyte production
  • Catalyst production
  • Precipitation technologies
  • Any crystal-growth or particle-growth fluidized bed