A profitability requirement for biorefineries is the integral use of raw materials through efficient and optimized fractionation processes. Supercritical carbon dioxide has been stated as a promising green solvent which advantages have been previously suggested in the literature. This work evaluates the effect of subcritical and supercritical CO₂ in both the hydrothermal treatment and the organosolv delignification, either as individual stages or as sequential processes, using pine sawdust, chips, and milled chips as raw materials. Both, the hydrothermal and the organosolv trials were first performed according to simple factorial designs, followed by a set of extra experiments for further understanding of the pine behavior. Carbohydrates content in the hydrothermal liquors and structural carbohydrates and lignin in the final pulps were analyzed. The yield (percentage of final biomass over original biomass) of the hydrothermal trials ranged from 76.2%–99.2%. CO₂ effect on yield and hemicelluloses removal is more noticeable at shorter periods and low (120 °C) and mild temperatures (160 °C), and it weakens as reaction time and temperature increase. The delignification rate during organosolv pulping ranged between 10.3 % and 70.1 %. For industrial sawdust, the presence of CO₂ during organosolv pulping significantly decreased delignification. The effect of hemicelluloses removal before organosolv pulping varies depending on the raw material, but in general, has a deleterious effect on delignification of pulps.

生物炼油厂的盈利能力要求是通过有效和优化的分馏工艺来整合使用原材料。据称超临界二氧化碳是一种有前途的绿色溶剂，其优点先前已在文献中提出。这项工作评估了亚临界和超临界CO _2的影响在水热处理和有机溶剂脱木素中，可以使用松木屑，木片和磨碎的木片作为原料，分为单个阶段或顺序过程。首先根据简单的阶乘设计进行水热试验和有机溶剂试验，然后再进行一组额外的实验，以进一步了解松木的行为。分析了热液中的碳水化合物含量以及最终纸浆中的结构性碳水化合物和木质素。水热试验的产量（最终生物质占原始生物质的百分比）在76.2％至99.2％之间。一氧化碳₂在较短的时间和低温（120°C）和温和的温度（160°C）下，对产量和半纤维素去除的影响更为明显，并且随着反应时间和温度的升高而减弱。有机溶剂制浆过程中的脱木素率在10.3％和70.1％之间。对于工业木屑，有机溶剂制浆过程中CO ₂的存在显着降低了脱木素作用。有机溶剂制浆之前去除半纤维素的效果因原料而异，但通常对纸浆的脱木质素具有有害作用。