High-solid conditions are desirable in pretreatment of lignocellulosic biomass. An advanced dilute-acid pretreatment reactor has been developed at National Renewable Energy Laboratory (NREL). It is a continuous auger-driven reactor that can be operated with high-solid charge at high temperature and with short residence time resulting in high productivity and high sugar concentration. We investigated the kinetics of the reactions associated with dilute-acid pretreatment of corn stover, covering the reaction conditions of the NREL reactor operation: 155–185 °C, 1–2 wt % sulfuric acid concentration, and 1:2 solid:liquid ratio. The experimental data were fitted to a first-order biphasic model which assumes that xylan is composed of two different fragments: fast and slow reacting fractions. Because of the high solid loading conditions, a significant amount of xylose oligomers was observed during the pretreatment. The oligomers were included as an intermediate entity in the kinetic model. The effect of acid concentration was incorporated into the pre-exponential factor of the Arrhenius equation. The kinetic model with best-fit kinetic parameters has shown good agreement with experimental data. The kinetic parameter values of the proposed model were noticeably different from those previously reported. The activation energies of xylan hydrolysis are lower and the acid exponents are higher than the average of literature values. The proposed model can serve as a useful tool for design and operation of pretreatment systems pertaining to corn stover.

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高固相条件下稀稀酸催化玉米秸秆半纤维素水解反应动力学模型

在木质纤维素生物质的预处理中需要高固相条件。国家可再生能源实验室（NREL）已开发出一种先进的稀酸预处理反应器。它是一个连续的螺旋钻驱动的反应器，可以在高温下以高固体装料运行，并且停留时间短，从而可以实现高生产率和高糖浓度。我们研究了与玉米秸秆稀酸预处理有关的反应动力学，涵盖了NREL反应器操作的反应条件：155–185°C，1-2 wt％的硫酸浓度和1：2的固液比。实验数据拟合到一阶双相模型，该模型假定木聚糖由两个不同的片段组成：快速和慢速反应级分。由于高固体负载条件，在预处理期间观察到大量的木糖低聚物。该低聚物被包括为动力学模型中的中间实体。酸浓度的影响已纳入Arrhenius方程的指数前因子。具有最佳拟合动力学参数的动力学模型已与实验数据很好地吻合。所提出的模型的动力学参数值与先前报道的那些明显不同。木聚糖水解的活化能较低，酸指数高于文献中的平均值。提出的模型可以作为玉米秸秆预处理系统的设计和运行的有用工具。酸浓度的影响已纳入Arrhenius方程的指数前因子。具有最佳拟合动力学参数的动力学模型已与实验数据很好地吻合。所提出的模型的动力学参数值与先前报道的那些明显不同。木聚糖水解的活化能较低，酸指数高于文献中的平均值。提出的模型可以作为玉米秸秆预处理系统的设计和运行的有用工具。酸浓度的影响已纳入Arrhenius方程的指数前因子。具有最佳拟合动力学参数的动力学模型已与实验数据很好地吻合。所提出的模型的动力学参数值与先前报道的那些明显不同。木聚糖水解的活化能较低，酸指数高于文献中的平均值。提出的模型可以作为玉米秸秆预处理系统的设计和运行的有用工具。所提出的模型的动力学参数值与先前报道的那些明显不同。木聚糖水解的活化能较低，酸指数高于文献中的平均值。提出的模型可以作为玉米秸秆预处理系统的设计和运行的有用工具。所提出的模型的动力学参数值与先前报道的那些明显不同。木聚糖水解的活化能较低，酸指数高于文献中的平均值。提出的模型可以作为玉米秸秆预处理系统的设计和运行的有用工具。