稻壳灰负载K2CO3催化制备生物柴油

摘要

以廉价的稻壳(RH)为原料，制备了 K2CO3负载稻壳灰(RHA)的固体碱催化剂，用于催化制备生物柴油.利用 X-射线衍射(XRD)、N2吸脱附、X 射线能谱(EDS)对催化剂的结构进行了表征，并考察了 K2CO3负载量、催化剂用量、反应物的醇油摩尔比和反应时间等因素对生物柴油产率的影响以及催化剂的可重复性使用．实验结果表明：稻壳在800℃下焙烧后制备的K2CO3/HRA催化剂，当K2CO3负载量为50%、催化剂用量为16%、醇油摩尔比为12∶1、在60℃下反应70,min 后，生物柴油产率为92.6%．催化剂在重复使用5次以后，生物柴油产率降至66.8%，主要原因是催化剂中K元素的流失．%Rice husk ash as solid waste from agriculture was served as the support for K2CO3 to prepare solid base catalyst for biodiesel production. The structures of the catalysts were characterized by X-ray diffraction (XRD),N2 adsorption-desorption and energy dispersive X-ray spectroscopy (EDS). The effects of various parameters such as mass fraction of K2CO3 loading,catalyst loading,molar ratio of methanol to oil and reaction time on the yield of biodiesel and the catalyst reusability were investigated. The experimental results revealed by using the rice husk burned at 800℃as the support,a maximum biodiesel yield of 92.6%was obtained under the optimal conditions with catalyst loading being 16%,molar ratio of methanol to oil 12∶1,reaction time being 70 min and K2CO3 loading being 50%.The biodiesel yield decreased to be 66.8%after five runs of reuse and the deactivation of the catalyst was mainly caused by potassium leaching in the reaction mixture.