Fast pyrolysis is one of the most promising conversion processes for producing advanced biofuels, which can be used as substitute for fuel oils or chemicals. Herbaceous biomass due to its comparatively high amount of cellulose and catalytically active inorganic content results in pyrolysis oil with high water content even if the original biomass was dry. Such bio-oil separates into two phases: an upper aqueous phase and a bottom tarry phase. The phase separation by decantation is not an efficient method to reduce the water content and total acid number because a part of valuable components will be lost to the aqueous phase. To improve the quality of bio-oils producing single-phase liquids by staged condensation seems to be the better method. The minimum condensation temperature which leads to single-phase liquid bio-oils was determined to be around 66°C for wheat/barley straw and 62°C for miscanthus. A further increase in temperature will result in bio-oils with lower water content and total acid number, but goes along with higher losses of organics to the second condensation stage.

中文翻译：

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分馏冷凝改进秸秆和芒草的快速热解生物油

快速热解是生产先进生物燃料的最有前景的转化工艺之一，可用作燃料油或化学品的替代品。草本生物质由于其较高量的纤维素和催化活性无机含量导致即使原始生物质是干燥的也具有高含水量的热解油。这种生物油分离成两相：上层水相和下层焦油相。通过倾析进行相分离不是降低水含量和总酸值的有效方法，因为一部分有价值的组分将损失到水相中。为了提高生物油的质量，通过分级冷凝生产单相液体似乎是更好的方法。导致单相液体生物油的最低冷凝温度被确定为小麦/大麦秸秆的 66°C 和芒草的 62°C 左右。温度的进一步升高将导致生物油具有较低的水含量和总酸值，但伴随着更高的有机物损失到第二冷凝阶段。