废食用油活性炭脱色工艺的研究

Decoloration of waste vegetable oil by activated carbon adsorption

脱色处理是提高废食用油油品质量、利用其生产生物柴油的关键环节之一。研究餐饮废食用油活性炭吸附脱色工艺,考察典型木质活性炭和煤基活性炭对脱色效果的影响,并将活性炭结构、性能指标与其脱色能力进行关联。结果表明,以弱粘性煤和褐煤为原料制备的活性炭对废食用油脱色效果较好;活性炭的总孔容积、总比表面积、微孔比表面积、微孔容积、碘值和亚甲基蓝值等性能指标与脱色效果关联度不大,而活性炭的孔径和中孔容积是决定活性炭脱色效果的主要指标。优化后废食用油活性炭脱色工艺的主要参数是：活性炭用量7%,炭粒度100～300目,脱色温度90～120℃,吸附时间为30 min,搅拌速度为10 r/min,废食用油的脱色率在50%～65%。

Decoloration of waste vegetable oil plays an important role in the improvement of oil quality and the process of preparation of biologic diesel from recycled oil. The effects of origin from representative ligneous and eoaly activated carbons, structure, capability of activated carbons and process parameters on the decoloration efficiency were experimentally investigated. The results show that activated carbon based on lignite and weakly caking coal is better for decoloration. The specifications of activated carbon such as total pore volume, specific surface area, micro-pore specific surface area, micro-pore volume, iodine number value, methylene blue number of activated carbon are not obviously relevant to its decoloration capacity. Meanwhile, meso-pore volume and av- erage pore diameter of activated carbon are proper indices. The weakly caking coal-based activated carbon is chosen as decolorant and the optimized parameters for decoloration process is established as followings： activated carbon concentration is 7% ; sizes of activated carbon is 100 -300 mesh ; initial decoloration temperature is 90 - 120℃ ; adsorption time is 30 min and agitating rate is 10 r/min, and as a result the decoloration rate can reach 50% -65%.