Volatile organic compound (VOC) off-gassing behavior of thermally treated biomass intended for bioenergy production has recently been shown to be vastly different from that of untreated biomass. Simple measures to reduce emissions, such as controlled ventilation and prolonged storage time, have been suggested but not yet studied in detail. In the present study, we monitored how VOC off-gassing was reduced over time (24–144 h) in enclosed storage with and without ventilation. Steam-exploded bark was collected directly from a pilot-scale steam explosion plant as well as before and after subsequent pelletizing. Active Tenax-TA absorbent sampling of VOCs was performed from the headspaces of a bench-scale sample storage setup. The impact of storage time and ventilation on VOC levels was evaluated through multivariate statistical analysis. The results showed that relative VOC concentrations in the headspace were reduced by increased storage time, with heavier VOCs reduced at a higher rate. VOC composition was neither reduced nor shifted by controlled intermittent ventilation during storage; instead, VOC levels equilibrated at the same levels as those stored without ventilation, and this was independent of the process step, storage time, or number of ventilations.

中文翻译：

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减少粒状蒸汽爆破树皮生产过程中的挥发性有机化合物脱气：储存时间和通风控制的影响

最近显示，用于生物能源生产的热处理生物质的挥发性有机化合物（VOC）脱气行为与未经处理的生物质有很大差异。已经提出了减少排放的简单措施，例如控制通风和延长储存时间，但尚未进行详细研究。在本研究中，我们监测了封闭通风条件下和不通风条件下如何随时间（24-144 h）减少VOC排放。蒸汽炸树皮直接从中试规模的蒸汽炸药厂以及随后的造粒前后收集。主动式Tenax-TA吸收剂对VOC的采样是从台式样品存储装置的顶部空间进行的。通过多变量统计分析评估了储存时间和通风对VOC水平的影响。结果表明，随着存储时间的增加，顶空中的相对VOC浓度降低，而较重的VOC则以更高的速率降低。在储存过程中，通过控制间歇通风，VOC的成分既不会减少也不会移动。取而代之的是，VOC的水平与无通风条件下的水平保持平衡，这与工艺步骤，存储时间或通风量无关。