Abstract
Semi-coke is the product of low-rank coal by pyrolysis at low temperature. If semi-coke could be used as fuel of industrial pulverized coal boilers, it will widen the fuel range of the industrial pulverized coal boilers and effectively promote the coal staged utilization. As the semi-coke need higher temperature than bituminous coal for its ignition and combustion process, the NOx emission will rapidly increase with the rising of temperature. So, decreasing the NOx is an important task in its utilization. In this paper, the NOx emission rules at the higher fuel-rich zone temperature and properties of semi-coke air-staged combustion were explored by two-stage drop-tube furnace. In the air-staged combustion experiments, the influence of fuel-rich zone temperature and the ratio of air on NOx emission and combustion behavior were investigated. The results indicate that the NOxemission concentration of non-staged combustion rises with fuel-rich zone temperature and the excess air coefficient in its combustion process. The air-staged combustion could visibly reduce the NOx emission in the combustion process. As the Fig. 32.1 shows, the optimum ratio of secondary air is 0.56, at which NOx emission concentration is under 120 mg/m3 and the burn-out rates were above 90%. The conclusions of the burn-out rate and the decrease rate of NOx can be used to guide the industry enlargement experiment in running conditions.
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Acknowledgements
This work was supported by the China Coal Science and Technology Group Innovation Fund Project (No. 2018MS003).
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Li, H., Wang, N., Yang, S., Zhang, X., Cui, Y., Zhou, J. (2022). Investigation on NOx Formation Characteristics During Semi-coke Air-Staged Combustion. In: Lyu, J., Li, S. (eds) Clean Coal and Sustainable Energy. ISCC 2019. Environmental Science and Engineering. Springer, Singapore. https://doi.org/10.1007/978-981-16-1657-0_32
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DOI: https://doi.org/10.1007/978-981-16-1657-0_32
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