Catalytic pyrolysis of corn straw with magnetic solid acid catalyst to prepare levulinic acid by response surface methodology
2018
Li, Xueqin | Lei, Tingzhou | Wang, Zhiwei | Li, Xiangyu | Wen, Mingyu | Yang, Miao | Chen, Gaofeng | He, Xiaofeng | Xu, Haiyan | Guan, Qian | Li, Zijie
This study investigated methods to optimize the process conditions for preparing levulinic acid (LA) using magnetic ferric oxide/SO42- biomass-based solid acid, to catalyze pyrolysis of corn straw using response surface methodology (RSM). The measured parameters were quality of liquid-solid ratio (QLSR), catalyst dosage (CDe), hydrolysis temperature (HT) and hydrolyzation duration (HD). The mathematical model of the quadratic polynomial of LA had a P-value less than 0.005, and the loss of quasi P-value was less than 0.01; the R2 value of 0.9969 indicates that the model was highly significant. The coefficient of variation was 3.02% (<10%), indicating that the model had high reliability. The optimal process conditions for preparing LA were determined by analyzing the three-dimensional surface and contour plots with a regression model equation. Using the Box-Behnken design to optimize the process conditions, the most favorable values of QLSR, CDe, HT and HD were 17.2:1 (V/W, mL:g), 3 g, 249.66 °C, and 67.3 min, respectively. Under optimized conditions, the maximum yield of LA was 23.17%, compared to the predicted value of 23.05%; the relative deviation between the two methods was 0.12%, indicating good repeatability. This study demonstrates that using RSM to optimize the conditions of LA preparation is feasible and has a very good application value.
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