Biomass Fly Ash

Ground Biomass Fly Ash


Problem: Large brewery, Grupo Modelo, wishes to recycle waste grain and malt from the brew process for the production of electric power. Handling the biomass ash cleanly and economically was required.

Solution: Macawber pneumatic conveying systems were used to convey boiler bottom ash and fly ash away to storage. The biomass is dried and transferred to a boiler where it is burned with #6 oil. The biomass fly ash is gathered from four electrostatic precipitator (ESP) hoppers and pneumatically conveyed to an ash silo. The bottom ash is crushed and transferred a short distance via customer’s mechanical conveyor to a pneumatic conveyor where it is transferred to an ash silo for truck loading.

Download Case Study: Ground Biomass Fly Ash – Grupo Modelo (pdf)


  • Material: Brewer Grain Fly Ash, Brewer Grain Bottom Ash, (brewer grain fired with #6 oil)
  • Bulk Density: Aerated 570-730 kg/m3 (36-76 lb/ft3)
  • Size: Fly Ash: 100%<100mesh, Bottom Ash: 300x150x65mm (max)
  • Temperature: 161°C – 300°C
  • Moisture Content: ~0%
  • Condition: Free flowing when aerated


  1. Minimize wear and air usage.
  2. Reliable and consistent conveying.
  3. Operate with -15.1” wc vacuum in baghouse.
  4. Operate with elevated bottom ash temperature of 300ºC.


  • Transfer Capacity BA: 635 kg/hr (1400 lb/hr), FA: 657 kg/hr (1450 lb/hr)
  • Conveying Distance BA: 120m (394ft), FA: 56m (184ft)
  • Reception Points One
    1. System operation is stable, reliable and efficient.
    2. System capacity exceeded specified rates.
    3.  Air consumption was below MEI quoted average.