Grindelia squarrosa, known as gumweed, is a shrub that grows in arid lands in North America with up to 8% biocrude (or bio-oil) content that can be extracted by using a common solvent extraction method. This solvent-extracted biocrude (SEB) has nearly 24 wt% oxygen, which is not suitable for direct combustion as a bio-oil or biodiesel. In this study, supercritical water (SCW) upgrading is used to reduce the oxygen of the SEB and increase the fuel value by creating lighter oil fractions. Treatment for 30 min reduces the oxygen content from 24.1 ± 1.6 (for raw SEB) to 7.2 ± 0.7%, 7.1 ± 0.4%, and 6.9 ± 0.6% at 380, 400, and 420 °C respectively. The addition of palladium on carbon (Pd/C) catalyst at 400 °C further reduces the oxygen content to 4.8 ± 0.7%. This removal in oxygen content is shown in the reduction of carboxylic acid compounds in the oils. Without having to use hydrogen, such as with the traditional hydrodeoxygenation process, the SCW upgrading has rather high energy yields for the oils which all have higher heating values between 41.0 and 42.8 MJ kg⁻¹ (with no significant effect of temperature or catalyst). Treatment at 400 °C had the highest energy yield at 76.4 ± 1.7%, and treatment with the Pd/C catalyst at 400 °C had the lowest at 61.4 ± 2.8%. These energy yields, higher heating values, and low oxygen contents show that SCW can effectively be used to convert gumweed-derived SEB into a valuable bio-oil.

甘草称为杂草，是一种灌木，生长在北美干旱地区，具有高达8％的生物原油（或生物油）含量，可以使用常规溶剂提取方法进行提取。这种溶剂萃取的生物原油（SEB）具有近24 wt％的氧气，不适合作为生物油或生物柴油直接燃烧。在这项研究中，超临界水（SCW）升级用于减少SEB的氧气并通过产生更轻的油馏分来增加燃料价值。在380、400和420°C下处理30分钟可使氧气含量分别从24.1±1.6（对于原始SEB）降低到7.2±0.7％，7.1±0.4％和6.9±0.6％。在400°C下添加钯碳（Pd / C）催化剂可将氧含量进一步降低至4.8±0.7％。氧含量的这种去除在油中羧酸化合物的还原中显示。^-1（对温度或催化剂无明显影响）。在400°C下处理的能量产率最高，为76.4±1.7％，在400°C下使用Pd / C催化剂处理的能量产率最低，为61.4±2.8％。这些能量产量，更高的发热量和低氧含量表明，SCW可有效地用于将口香糖衍生的SEB转化为有价值的生物油。