钙基固体碱催化微藻油脂制备生物柴油
发布时间：2018-10-17 10:10
【摘要】：生物柴油就是一种首选优质燃料,因为它与石化柴油相比有更高的含氧量,在柴油发动机中燃烧产生的CO2、SOx、CO、硫、烃类、芳香族化合物和烟雾等低于石化柴油燃烧产生的量,这有利于减小温室效应对环境造成的不良影响。工业生产中植物油脂或动物脂肪中的脂肪酸甘油酯与甲醇在NaOH或其它均相碱催化剂的环境下,会发生酯交换反应,并生成脂肪酸甲酯(目的产物),同时伴随甘油副产物的生成。这些催化剂是便宜和非常有效的,但从产物中彻底洗涤除去它们是非常复杂,易皂化使生物柴油和甘油难分离,并且洗涤过程中会产生大量的废液。目前,很多固体碱催化剂具有较高的反应速率被开发生产生物柴油,并且产物易分离,对环境无污染催化剂还可以重复使用。本文采用共沉淀法先制备钙镁铝类水滑石化合物,以其为前驱体经高温煅烧后制得钙镁铝复合金属氧化物催化剂,并将其用于生产生物柴油。(1)首先重点考察了制备钙镁铝类水滑石的反应条件,即煅烧温度、碱度、碱土金属含量、醇油比和反应温度对生物柴油转化率的影响。最佳制备条件为煅烧温度400℃,钙镁铝摩尔比为1.5:4.5:2,醇油比为14:1,催化剂用量为制备生物柴油的原料油的4.5wt%,反应温度为65℃,反应时间5h时,生物柴油的转化率达到最高93%。利用XRD、TG-DTG、CO2-TPD、BET、FT-IR和SEM等表征手段分析最终制得的催化剂,并研究钙离子的引入对催化剂碱性、比表面积和酯交换反应性能的影响。(2)从微藻中提取制备生物柴油的原料油,而酯交换反应中的固体碱催化剂要在酸值小于2.0mgKOH/g的条件下才有催化性能,而微藻提取的油脂酸值高于此值,因此在酯交换反应前要对微藻油进行预酯化处理,就是将微藻油中的酸值降到2.0mgKOH/g以下。脱酸工艺条件为:温度为65℃,恒温后加入98%甲醇-浓硫酸的混合溶液,加入的甲醇量为油重的10wt%,搅拌2h后停止反应,最后用蒸馏水洗涤并分离。
[Abstract]:Biodiesel is the preferred quality fuel because it has a higher oxygen content than petrochemical diesel, and combustion in diesel engines produces less CO2,SOx,CO, sulfur, hydrocarbons, aromatic compounds and smoke than petrochemicals. This helps to reduce the adverse impact of Greenhouse Effect on the environment. In the industrial production of vegetable oil or animal fat fatty acid glycerides and methanol in the environment of NaOH or other homogeneous alkali catalyst will take place transesterification reaction and the formation of fatty acid methyl ester (the target product) accompanied by the formation of glycerol by-products. These catalysts are cheap and very effective, but it is very complicated to remove them completely from the products. It is easy to saponify biodiesel and glycerol to be difficult to separate, and a large amount of waste liquid will be produced in the washing process. At present, many solid base catalysts have been developed to produce biodiesel at a high reaction rate, and the products are easy to be separated. In this paper, calcium, magnesium and aluminum hydrotalcite compounds were prepared by coprecipitation method. It was used to produce biodiesel. (1) the effects of calcination temperature, alkali earth metal content, ratio of alcohol to oil and reaction temperature on the conversion of biodiesel were investigated. The optimum preparation conditions were as follows: calcination temperature 400 鈩，
本文编号：2276319
[Abstract]:Biodiesel is the preferred quality fuel because it has a higher oxygen content than petrochemical diesel, and combustion in diesel engines produces less CO2,SOx,CO, sulfur, hydrocarbons, aromatic compounds and smoke than petrochemicals. This helps to reduce the adverse impact of Greenhouse Effect on the environment. In the industrial production of vegetable oil or animal fat fatty acid glycerides and methanol in the environment of NaOH or other homogeneous alkali catalyst will take place transesterification reaction and the formation of fatty acid methyl ester (the target product) accompanied by the formation of glycerol by-products. These catalysts are cheap and very effective, but it is very complicated to remove them completely from the products. It is easy to saponify biodiesel and glycerol to be difficult to separate, and a large amount of waste liquid will be produced in the washing process. At present, many solid base catalysts have been developed to produce biodiesel at a high reaction rate, and the products are easy to be separated. In this paper, calcium, magnesium and aluminum hydrotalcite compounds were prepared by coprecipitation method. It was used to produce biodiesel. (1) the effects of calcination temperature, alkali earth metal content, ratio of alcohol to oil and reaction temperature on the conversion of biodiesel were investigated. The optimum preparation conditions were as follows: calcination temperature 400 鈩，
本文编号：2276319
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