Experimental investigation on NO emission of semi-coke under high temperature preheating combustion technology

• Published in: Fuel (Guildford) 2021-01, Vol.283 (C), p.119293, Article 119293
• Main Authors: Lv, Zhaomin, Xiong, Xiaohe, Yu, Shilin, Tan, Houzhang, Xiang, Baixiang, Huang, Jun, Peng, Jianghua, Li, Peng
• Format: Article
• Language: English
• Subjects: Air ratio; Air temperature; Burnout; Coke; Combustion; Combustion characteristic; Combustion efficiency; Combustion temperature; Emission analysis; Heating; High temperature; Low temperature; Nitrogen oxides; NOx emission; Reduction; Semi-coke; Stoichiometry; Tube furnaces
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2020.119293

•Proposing a method of controlling NOx emissions and promote burnout from semi-coke combustion.•Analyzing the effects of higher preheating temperature and combustion temperature on NO emissions.•Higher preheating temperature helps substantial N2 to be generated in the preheating furnace.•Char plays an important role in reducing NO when the combustion temperature is high under fuel-rich conditions. Low temperature (1000 °C) has not been reported. Aiming to acquire a lower NOx emission, the preheating combustion technique with a higher preheating temperature (>1000 °C) has been tested on a two-stage drop-tube furnace in this paper. This work mainly focused on the preheating temperature and the combustion temperature these two factors on the NO emission and burnout characteristic. Results showed that higher preheating temperature (>1000 °C) could further lower the NO emission and enhance the combustion efficiency due to the early conversion of char-N to N2. The NO reduction percentage can reach as high as 74% as the preheating temperature increased to 1400 °C. Moreover, the NO reduction degree was more significant in the fuel-rich conditions (i.e., α