Northeast States for Coordinated Air Use Management, Boston, MA, USA.
J Air Waste Manag Assoc. 2022 Jul;72(7):647-661. doi: 10.1080/10962247.2022.2056660.
Homeowners burn wood of a wide range of species and moisture content (MC) in residential cordwood and pellet stoves. An effective emission certification test protocol must account for and accurately measure the impact of those variables in order to ensure a reasonable correlation between laboratory results and in-use emissions and to promote the design and manufacture of cleaner burning appliances. This study explored the effect of wood species and MC on emissions and efficiency in four cordwood and four pellet stoves. PM emissions were consistently lower with pellets manufactured from softwood than for hardwood species and were highly correlated with ash content. Higher MC oak fuel substantially increased PM emissions in a non-catalytic cordwood stove; however, a hybrid cordwood stove was able to meet federal emissions limits even with the higher MC fuel. The results of this study, in combination with previous research, suggest that certification tests that use softwood fuel likely report lower emissions than tests that use hardwood. Requiring hardwood and higher MC cordwood fuel in certification tests would enable the assessment of an appliance's ability to operate well even when fuel conditions are not optimized.: The emission testing results reported in this paper call into question the adequacy of the fuel moisture content and fuel species specifications in testing protocols approved for certifying compliance with EPA's New Source Performance Standards for cordwood and pellet stoves. We recommend changes in those specifications, including the prohibition of testing with Douglas fir and other low ash softwood species, requiring the use of cordwood test fuel with a higher moisture content, and requiring pellet stoves to be tested using hardwood pellets. Adoption of these measures would increase the replicability of tests. allow for the identification of stoves that are unlikely to perform well in the field when fuel conditions are not ideal, and, ultimately, result in the design of cleaner burning stoves.
住户在住宅用薪柴和颗粒壁炉中燃烧多种木材和不同水分含量（MC）的木材。有效的排放认证测试协议必须考虑并准确测量这些变量的影响，以确保实验室结果与使用中的排放之间具有合理的相关性，并促进更清洁燃烧器具的设计和制造。本研究探讨了四种薪柴和四种颗粒壁炉中木材种类和 MC 对排放和效率的影响。由软木制成的颗粒产生的 PM 排放始终低于硬木，并且与灰分含量高度相关。高 MC 的橡木燃料会在非催化薪柴壁炉中大幅增加 PM 排放；然而，混合薪柴壁炉即使使用更高 MC 的燃料也能够满足联邦排放限制。本研究的结果与之前的研究相结合，表明使用软木燃料的认证测试可能会报告比使用硬木燃料的测试更低的排放。在认证测试中要求使用硬木和更高 MC 的薪柴燃料，将能够评估器具即使在燃料条件不理想的情况下也能良好运行的能力。本文报告的排放测试结果对经批准用于认证符合 EPA 薪柴和颗粒壁炉新源性能标准的测试协议中的燃料水分含量和燃料种类规格的充分性提出了质疑。我们建议修改这些规格，包括禁止使用花旗松和其他低灰分软木，要求使用水分含量更高的薪柴测试燃料，以及要求颗粒壁炉使用硬木颗粒进行测试。采用这些措施将增加测试的可重复性，允许识别在燃料条件不理想时不太可能在现场发挥良好性能的炉子，并最终设计出更清洁的燃烧炉子。
