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NO reduction by different tar agents and model compounds in a drop-tube reactor

Bunman, Yutthasin, Do, Hai-Sam, Zeng, Xi, Han, Zhennan, Gao, Shiqiu, Xu, Guangwen
Fuel processing technology 2018 v.172 pp. 187-194
acetates, acetic acid, benzene, biomass, coal tar, combustion, distilled spirits, fluidized beds, heptane, lees, models, nitric oxide, phenol, pyrolysis, reducing agents, sawdust, temperature
Our previous studies suggested that the biomass tar derived from pyrolysis of distilled spirit lees (DSL) is an attractive agent for lowering NOx emission in the circulating fluidized bed decoupling combustion (CFBDC) process. The present work is furthered to evaluate the capabilities of other tar agents including sawdust (SD) tar and Xianfeng (XF) coal tar for NO reduction in a lab-scale drop-tube reactor. Additionally, five representative model tar compounds including phenol, benzene, acetic acid, methyl acetate and heptane were also tested to clarify the contribution of the main components in tar agents to NO reduction. The realized NO reduction efficiency by tar obviously varied with the reburning stoichiometric ratio (SR) and reaction temperature. At a specified mass feeding rate of reductant, say 0.15g/min, the NO reduction realized by the SD tar is higher than that by the XF coal tar, and was even better than that by the DSL tar obtained in our previous study. Testing the NO reduction by model tar compounds revealed that phenol plays an important role in enabling its good NO reduction for the SD tar. The major understanding from the work is that the compounds containing at least an aromatic ring (e.g. phenol, benzene, etc.) are the major contributor for reducing NO in either biomass tar or coal tar.