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Title: Combustion properties of micronized coal for high intensity combustion applications

Technical Report ·
DOI:https://doi.org/10.2172/7129417· OSTI ID:7129417

Results are presented of an investigation of combustion related properties of micronized coal feeds (all particles less than 40 microns), mixing characteristics of centrifugally driven burner devices, and aerodynamic characteristics of micronized coal particles related to centrifugal mixing for high intensity combustion applications. Combustion related properties investigated are the evolution of fuel bound nitrogen and coal associated mineral matter during the initial stages of combustion. Parent and beneficiated micronized coal samples, as well as narrow size cut samples from a wide range of coal ranks, were investigated using a multireactor approach. The multireactor approach allowed the experimental separation of different aspects of the fuel nitrogen evolution process, enabling a comprehensive understanding of FBN to be formulated and empirical rate constants to be developed. A specially designed on-line gas analysis system allowed nitrogen balance to be achieved. A combined nitrogen and ash tracer technique allowed the quantitative determination of tar yields during rapid devolatilization. Empirical kinetic rates are developed for the evolution of FBN with tar at low temperatures and the appearance of HCN from tar and char species at high temperatures. A specially designed phase separation system, coupled to separate aerosol and char segregation trains, allowed the possible formation of ash aerosol by rapid devolatilization to be monitored. Compensated thermocouple, hot wire anemometry, and digital imaging techniques are employed to characterize the mixing properties of a centrifugally driven combustor. Analytical and experimental investigations of the fidelity of micronized coal particles to gas stream trajectories in the strong centrifugal fields are performed. Both spherical and nonspherical particle morphologies are considered analytically. 14 refs., 141 figs., 34 tabs.

Research Organization:
United Technologies Research Center, East Hartford, CT (United States)
Sponsoring Organization:
DOE/FE
DOE Contract Number:
AC22-85PC80263
OSTI ID:
7129417
Report Number(s):
DOE/PC/80263-T24; UTRC-957253-F; ON: DE90000643
Country of Publication:
United States
Language:
English