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Title:
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Devolatilisation of pulverised coal: experiments in ECN's AEFGC-simulator
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Author(s):
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Published by:
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Publication date:
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ECN
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1995
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ECN report number:
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Document type:
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ECN-I--95-028
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Other
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Number of pages:
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Full text:
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43
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Download PDF
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Abstract:
The devolatilisation behaviour of Goettelborn coal was studied in alab-scale coal characterisation facility, the so-called Atmospheric
Entrained-Flow Gasification and Combustion simulator (AEFGC-simulator).
Volatile matter yield and nitrogen release were determined for three size
fractions, viz. 44-63, 75-90 and 125-150 mum, and two operating modes. In
mode 1, a staged flat flame (methane/oxygen/nitrogen) burner was used as the
heat source and to provide the desired gaseous environment for the coal
particles, along with an electrically heated wall extending from the burner.
In this mode, the particle heating rate was in the order of 105 deg C/s and
the final gas temperature was 1000C or 1400C at a wall temperature of 1000C
or 1500C respectively. In mode 2, the facility was operated without the gas
burner, with typical particle heating rates of 103C/s and a final gas
temperature of approx. 850C. In this mode experiments were conducted in a
100% nitrogen atmosphere. In general, the actual volatile matter yield was
found to be 1-2.5 times higher than the proximate volatile matter yield.
Particle size appeared to have a significant influence on both the volatile
matter yield and nitrogen release in operating mode 1. Smaller particles
resulted in higher volatile matter yields and nitrogen releases than larger
particles. In operating mode 2, however, the effects of particle size on
volatile matter yield and nitrogen release were found to be less significant.
Both the volatile matter yield and the nitrogen release in operating mode 1
were considerably larger than in operating mode 2. This was attributed to the
large differences in heating rate and final temperature. Since the conditions
for operating mode 1 are much more representative for the actual conditions
in entrained-flow gasification and pulverised fuel combustion processes,
operating mode 1 is clearly to be preferred over operating mode 2. The
present test results indicate that the concept of using a staged flat flame
burner in conjunction with an electrically heated wall extending from the
burner is appropriate for low-cost lab-scale devolatilisation studies of
pulverised coal. 18 figs., 6 tabs., 22 refs.
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