Experimental research on lignite fluidized bed combustion
Burning lignite fuel in fluidized beds has many obvious advantages: (1) high heat accumulation in the fuel bed. (This provides a sufficient heat source to dry and preheat the lignite and helps high moisture lignite to ignite in time, resulting in a stable combustion condition); (2) the normal temperature range for fluidized beds is 850 to 950/sup 0/C (this is much lower than the lignite-deformation point); (3) ash erosion is not usually high; (4) since the operating temperature for a lignite fluidized bed boiler may relatively low, the load range can be much wider; (5) the erosion of the submerged tubes in lignite fluidized-bed boilers is not serious due to the relatively loose character of lignite ash; (6) the specific gravity of lignite ash is relatively low; (7) it's easier to ignite a fluidized-bed boiler; (8) when lignite fuel is thrown into the high-temperature fuel beds, the fuel is suddenly heated and crumbles easily by itself, allowing coal particles as-fired to be very coarse. At present, one of the main problems for existing fluidized-bed boilers is low combustion efficiency. The main reason for lower combustion efficiency and higher unburned combustible solids losses is the high carbon content in the fly-ash. The small particles may be blown off the high-temperature fluidized bed, resulting in an unburned carbon loss in the fly-ash. One of the important characteristics for firing lignite in fluidized-bed boilers is possibly that more volatile matter and small coal particles are burning in the suspension chamber (freeboard). The optimization of the combustion process in the suspension chamber to obtain better performance is an important factor in determining the combustion efficiency of lignite fluidized-bed boilers.
- Research Organization:
- Harbin Inst. of Technology, China
- OSTI ID:
- 6695972
- Report Number(s):
- CONF-820304-Vol.2
- Journal Information:
- Prepr. Pap. - Am. Chem. Soc., Div. Fuel Chem.; (United States), Journal Name: Prepr. Pap. - Am. Chem. Soc., Div. Fuel Chem.; (United States) Vol. 27:1; ISSN ACFPA
- Country of Publication:
- United States
- Language:
- English
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