Experimental and numerical study on oxy-fuel combustion of pyrolysis gas at ultra-rich conditions with non-premixed and partially premixed nozzles

• Published in: International journal of hydrogen energy Vol. 91; pp. 63 - 72
• Main Authors: Ren, Mengmeng, Tan, Ronglong, Zhao, Junxue, Zhao, Zitong, Zou, Chong, Li, Bin, Romero-Anton, N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 19.11.2024
• Subjects: Low metamorphic coal pyrolysis; Nozzle configuration; Oxy-fuel combustion; Rich combustion; Selective combustion; Nozzle configuration; Selective combustion; Rich combustion; Oxy-fuel combustion; Low metamorphic coal pyrolysis
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.10.118

To guide the nozzle design for a novel oxy-fuel combustion facilitated pyrolysis technology, oxy-fuel rich combustion of pyrolysis gas is investigated experimentally and numerically. Two numerical models are compared and validated by experimental observations, among which the Eddy Dissipation Concept model performs better in prediction of flame length, maximum temperature, species conversion and flame stability with the modified fine scale constant. Flame length is found to be inversely proportional to the mixing rate of fuel and oxidizer. For non-premixed nozzles, the mixing rate increases with the increase in difference between the inner and annular velocity. For partially premixed nozzles, higher annular velocity promotes the mixing. The selective combustion molar ratio of three fuel components in practical nozzles are between those in premixed flame and at thermodynamic equilibrium assumption. CH4 is consumed the most, while H2 consumption molar ratio to CH4 is 56%–69% and CO is net produced after the combustion. •The modified EDC model reasonably predicts flame appearance and blow-off limits.•Flame length is inversely proportional to the mixing rate of fuel and oxidizer.•For partially premixed nozzles, higher annular velocity promotes the mixing.•H2 consumption molar ratio to CH4 is 56%–69%, while CO is net produced.•For oxy-fuel rich combustion, yellow flame occurs at better premixed conditions.