Coal Gasifier Ash

Coal Gasifier Ash

Coal gasification is an upcoming clean coal technology whereby the carbon materials in the coal are removed before the combustion process takes place. The gasification process is proven and is operational in several commercial and demonstrational plants worldwide. In the case of our customer there was a need to handle waste material from the gasification process while keeping the customer’s process pressure up. Macawber achieved this requirement with two x 8/8-4/8 Denseveyor pressure letdown systems for removal of the waste material originating from coal gasifier baghouses and electro-static precipitators. The systems were designed to operate at baghouse and ESP pressure for filling and then lock down to atmospheric pressure for conveying the waste material away to storage while maintaining process upstream pressure.

Download Case Study: Gasifier Ash – China (PDF)


  • Material Gasifier Ash
  • Bulk Density Aerated 1,264 kg/m3 (79 lb/ft3)
  • Size 140 – 6 mesh
  • Temperature 150°C (302°F)
  • Moisture Content 2%
  • Condition Free flowing when aerated, highly abrasive.


  1. Pressure letdown lock system
  2. Reliable consistent conveying.
  3. Maintain low pipe and valve wear.
  4. Provide a competitive solution to previous poor supplier.


  • Transfer Capacity 7.5 Mt/h each system
  • Conveying Distance 80m (260ft)
  • Reception Points One per system
  • Air Consumption Average 4.5 Nm3/min (160scfm)
    1. System operation is stable, reliable and efficient
    2. Elevated pressure in baghouse and ESP is maintained
    3. Competitive solution beat customer expectation in quality and after sales service