【摘要】：生物柴油就是一種首選優(yōu)質(zhì)燃料,因?yàn)樗c石化柴油相比有更高的含氧量,在柴油發(fā)動(dòng)機(jī)中燃燒產(chǎn)生的CO2、SOx、CO、硫、烴類、芳香族化合物和煙霧等低于石化柴油燃燒產(chǎn)生的量,這有利于減小溫室效應(yīng)對(duì)環(huán)境造成的不良影響。工業(yè)生產(chǎn)中植物油脂或動(dòng)物脂肪中的脂肪酸甘油酯與甲醇在NaOH或其它均相堿催化劑的環(huán)境下,會(huì)發(fā)生酯交換反應(yīng),并生成脂肪酸甲酯(目的產(chǎn)物),同時(shí)伴隨甘油副產(chǎn)物的生成。這些催化劑是便宜和非常有效的,但從產(chǎn)物中徹底洗滌除去它們是非常復(fù)雜,易皂化使生物柴油和甘油難分離,并且洗滌過程中會(huì)產(chǎn)生大量的廢液。目前,很多固體堿催化劑具有較高的反應(yīng)速率被開發(fā)生產(chǎn)生物柴油,并且產(chǎn)物易分離,對(duì)環(huán)境無污染催化劑還可以重復(fù)使用。本文采用共沉淀法先制備鈣鎂鋁類水滑石化合物,以其為前驅(qū)體經(jīng)高溫煅燒后制得鈣鎂鋁復(fù)合金屬氧化物催化劑,并將其用于生產(chǎn)生物柴油。(1)首先重點(diǎn)考察了制備鈣鎂鋁類水滑石的反應(yīng)條件,即煅燒溫度、堿度、堿土金屬含量、醇油比和反應(yīng)溫度對(duì)生物柴油轉(zhuǎn)化率的影響。最佳制備條件為煅燒溫度400℃,鈣鎂鋁摩爾比為1.5:4.5:2,醇油比為14:1,催化劑用量為制備生物柴油的原料油的4.5wt%,反應(yīng)溫度為65℃,反應(yīng)時(shí)間5h時(shí),生物柴油的轉(zhuǎn)化率達(dá)到最高93%。利用XRD、TG-DTG、CO2-TPD、BET、FT-IR和SEM等表征手段分析最終制得的催化劑,并研究鈣離子的引入對(duì)催化劑堿性、比表面積和酯交換反應(yīng)性能的影響。(2)從微藻中提取制備生物柴油的原料油,而酯交換反應(yīng)中的固體堿催化劑要在酸值小于2.0mgKOH/g的條件下才有催化性能,而微藻提取的油脂酸值高于此值,因此在酯交換反應(yīng)前要對(duì)微藻油進(jìn)行預(yù)酯化處理,就是將微藻油中的酸值降到2.0mgKOH/g以下。脫酸工藝條件為:溫度為65℃,恒溫后加入98%甲醇-濃硫酸的混合溶液,加入的甲醇量為油重的10wt%,攪拌2h后停止反應(yīng),最后用蒸餾水洗滌并分離。
[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，

本文編號(hào)：2276319