CaZr 1- x Fe x O 3 催化热解甘蔗渣木质素制备酚类化合物

Abstract

Chemical conversion is an important approach to obtain chemical products from bagasse lignin (BL) which favors in resource and high. value utilization of lignin. A series of perovskite. type mixed ionic and electronic conductors CaZr1-xFexO3 (CZF-x; x = 0, 0.2, 0.4, 0.8, 1.0) were prepared via the solid state re. action method. The crystal form, morphology, metal valence state and thermal stability were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectric spectroscopy (XPS) and thermogravimetric analysis and differential thermal analysis (TG-DTA). Catalytic performance for producing phenolic compounds from bagasse lignin via catalytic pyrolysis was evaluated in a fixed bed micro. reactor. The results show that the CaZr1-xFexO3 pellets after calcinations deposit randomly in the form of irregular grains of flake with compact structure. As the doping amount of Fe increases, the characteristic peaks of mixed ionic and electronic conductor shift to large angle, the cell volume of crystal and the grain size decrease. Moreover, the pyrolysis temperature of BL was significantly reduced under the action of CaZr0.2 Fe0.8O3 (CZFO-0. 2). In the test of fixed bed micro. reactor, the yield of liquid product was 23.71%. The phenolic product was mainly consisting with phenols, guaiacyl groups, catechol and syringyl groups; their selectivities were 35.19%, 6.18%, 10.68% and 14.21% respectively. The rest of liquid products were benzenes and methoxy aromatics. The deactivated catalyst was regenerated by oxidation to removing the coke coated on the surface and exhibited the high structural stability and the better catalytic activity. Due to the enhancement of breakage for aromatic alkyl side chain by CZFO-0.2, the contents of CH4 and CmHn in BL pyrolysis gas increased.