Microfine coal combustion
The combustion characteristics of microfine coal (nominally 100% below 44 microns) are investigated with particular reference to flame length, fly ash particle size and ash fouling characteristics. Coals prepared by mechanical milling are compared with those prepared by an air-operated fluid energy mill. Reduced coal particle size is shown to possess the following advantages: - reduced support fuel requirement for ignition and flame stabilisation - reduced flame length and increased peak flame temperature - finer fly ash - increased furnace heat absorption associated with reduced gas exit temperatures. The possible disadvantages of increased NO(x) emission levels and increased milling costs are assessed. The development of a direct-fired mechanical mill system, which incorporates a classifier for the return of oversize coal for further grinding, is recommended. This should be used in combination with a staged, swirled burner to reduce NO(x) levels and maximise the use of available combustion volume.
Bibliographic Reference: EUR 11748 EN (1989) 89 pp., MF, ECU 4, blow-up copy ECU 7.50
Record Number: 199010134 / Last updated on: 1994-12-01
Original language: en
Available languages: en