复合粘结剂对生物质成型颗粒密度与能耗的影响

Using cotton stalks, wheat stalks and rape stalks as raw materials, molding experiments were carried out on a desktop molding unit by adding different composite binders to investigate the characteristics of biomass molding pellets. The results showed that for cotton stalks and wheat stalks, the relaxation density of the molded pellets after adding the binder was significantly increased compared with that of the molded pellets without adding the binder, and the energy consumption was reduced by more than 20%. Considering factors such as the quality of the molded pellets, energy consumption and economic cost, the mass ratios of the optimal composite binders (carboxymethyl cellulose, Al₂O₃, Fe₂O₃ and clay) for cotton stalk and wheat stalk molded pellets were 4∶4∶5∶7 and 3∶5∶6∶6 respectively, while for rape stalks, due to their own characteristics, their optimal molding method needs to be further explored. Through infrared spectroscopy and metallographic microscope image analysis, the carboxymethyl cellulose in the binder cross-links with the small particles in the molded pellets to form "bridge bonds" to strengthen the binding force between the raw material particles. However, due to the high content of extracts in rape stalks, the cuticle formed on the surface of the raw material particles hinders the interaction between the binder and the raw material particles.

以棉秆、麦秆和油菜秆为原料,通过向其中加入不同的复合粘结剂于台式模压单元上进行成型实验来考察生物质成型颗粒的特性。结果发现,对于棉秆和麦秆而言,加入粘结剂后的成型颗粒比未添加粘结剂的成型颗粒的松弛密度大幅提高,并且能耗减少20%以上。综合考虑成型颗粒品质、能耗以及经济成本等因素,棉秆和麦秆成型颗粒的最优复合粘结剂(羧甲基纤维素、Al_2O_3、Fe_2O_3和黏土)的质量比分别为4∶4∶5∶7和3∶5∶6∶6,而油菜秆由于自身特性,需进一步探讨其最佳成型方式。通过红外光谱和金相显微镜图像分析,粘结剂中的羧甲基纤维素与成型颗粒中微小粒子相互交联形成“桥键”加强原料粒子间的粘结力,但由于油菜秆中提取物含量较高,导致原料粒子表面形成的角质层阻碍粘结剂与原料粒子之间的相互作用。