Environmental Technologies Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.
Environ Sci Technol. 2018 Apr 3;52(7):4449-4456. doi: 10.1021/acs.est.7b05277. Epub 2018 Mar 26.
Nearly 40% of the world's population regularly cooks on inefficient biomass stoves that emit harmful airborne pollutants, such as particulate matter (PM). Secondary air injection can significantly reduce PM mass emissions to mitigate the health and climate impacts associated with biomass cookstoves. However, secondary air injection can also increase the number of ultrafine particles emitted, which may be more harmful to health. This research investigates the effect of secondary air injection on the mass and size distribution of PM emitted during solid biomass combustion. An experimental wood-burning cookstove platform and parametric testing approach are presented to identify and optimize secondary air injection parameters that reduce PM and other harmful pollutants. Size-resolved measurements of PM emissions were collected and analyzed as a function of parametric stove design settings. The results show that PM emissions are highly sensitive to secondary air injection flow rate and velocity. Although increasing turbulent mixing (through increased velocity) can promote more complete combustion, increasing the total flow rate of secondary air may cause localized flame quenching that increases particle emissions. Therefore, biomass cookstoves that implement secondary air injection should be carefully optimized and validated to ensure that PM emission reductions are achieved throughout the particle size range.
全球近 40%的人口经常在效率低下的生物质炉灶上做饭，这些炉灶会排放有害的空气污染物，如颗粒物（PM）。二次空气喷射可以显著减少 PM 质量排放量，从而减轻与生物质炉灶相关的健康和气候影响。然而，二次空气喷射也会增加超细颗粒的排放数量，这可能对健康更有害。本研究调查了二次空气喷射对固体生物质燃烧过程中 PM 排放的质量和粒径分布的影响。提出了一个实验性的柴火炉平台和参数测试方法，以确定和优化可减少 PM 和其他有害污染物的二次空气喷射参数。收集并分析了 PM 排放的粒径分辨测量结果，作为参数炉设计设置的函数。结果表明，PM 排放对二次空气喷射流速和速度非常敏感。虽然增加湍流混合（通过增加速度）可以促进更完全的燃烧，但增加二次空气的总流量可能会导致局部火焰熄灭，从而增加颗粒物排放。因此，实施二次空气喷射的生物质炉灶应仔细优化和验证，以确保在整个粒径范围内实现 PM 减排。
