Center for Urban Transport Emission Research, State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
QES Department, Novozymes (China) Biotechnology Ltd, Tianjin, 300457, China.
Environ Sci Pollut Res Int. 2019 Apr;26(10):9717-9729. doi: 10.1007/s11356-019-04396-8. Epub 2019 Feb 7.
The effect of air staging strategies on NO control was investigated on a 210-kW small-scale biomass boiler (SBB) and a 1.4-MW medium-scale biomass boiler (MBB). Considering the de-NO effect, as well as the convenience and economy for future wide use, the structures of the secondary air duct and the fuel feed tube were innovatively designed to solve the problems of the traditional prototype. The preliminary experiment showed that the lowest NO emission was achieved when the air excess (ε) was equal to 2.04. Then, additional operating modes were conducted on the MBB to further optimize the air staging strategies. The optimal air staging strategy of the MBB (the secondary to primary air flow ratio (λ) and the ε were equal to 0.13 and 0.76, respectively) could decrease the NO emission from 338.12 to 148.14 mg/m. Furthermore, the SO emissions and the lowest NO emission of the SBB and the MBB could meet most emission standards of China and some developed countries. The thermogravimetric analysis (TG) and combustion characteristics of the wood fuel showed that the air staging was a suitable de-NO technology for wood combustion, and the slagging was less likely to occur under the selected condition. Hence, the air staging technology was an effective and low-cost method for the emission reduction of biomass boilers. This study provided a practical basis for future research on the gas emission control of biomass boilers.
研究了空气分级策略对 NO 控制的影响，实验对象分别为一台 210kW 的小型生物质锅炉（SBB）和一台 1.4MW 的中型生物质锅炉（MBB）。考虑到脱氮效果，以及未来广泛应用的便利性和经济性，创新性地设计了二次空气管道和燃料进料管的结构，以解决传统原型存在的问题。初步实验表明，当过量空气系数（ε）等于 2.04 时，NO 排放最低。然后，在 MBB 上进行了额外的运行模式，以进一步优化空气分级策略。MBB 的最佳空气分级策略（二次空气与一次空气流量比（λ）和 ε 分别为 0.13 和 0.76）可将 NO 排放量从 338.12 降至 148.14mg/m³。此外，SBB 和 MBB 的 SO 排放和最低 NO 排放均能满足中国和一些发达国家的大部分排放标准。生物质燃料的热重分析（TG）和燃烧特性表明，空气分级是一种适用于木材燃烧的脱氮技术，在选定的条件下，结渣的可能性较小。因此，空气分级技术是生物质锅炉减排的一种有效且低成本的方法。本研究为未来生物质锅炉气体排放控制的研究提供了实践基础。
