【摘要】：隨著世界工業(yè)化和現(xiàn)代化進程的加快,對石油資源的需求量越來越大,然而大量使用石化燃料將會帶來能源危機和環(huán)境問題,因此尋找新型的可替代能源越來越受到關(guān)注。生物柴油由于具有可再生、綠色環(huán)保、可降解等優(yōu)點,被認(rèn)為是石化燃料最好的替代品。以高酸值油脂代替純植物食用油可以降低生產(chǎn)成本,提高生物柴油的競爭力。目前使用高酸值油脂制備生物柴油的過程可分為兩步:預(yù)酯化和酯交換。催化劑多以均相酸堿為主,而均相酸堿催化劑帶來產(chǎn)物不易分離、催化劑回收困難、水洗產(chǎn)生大量廢水、不能連續(xù)化生產(chǎn)等問題,針對這些問題,本文對兩種不同的固體催化劑(介孔碳基固體酸和硅酸鋰固體堿)及其在高酸值油脂制備生物柴油中的應(yīng)用進行系統(tǒng)研究。(1)以蔗糖為碳源、SiO_2為模板劑,采用碳化-磺化法制備介孔碳基固體酸催化劑,采用酸堿滴定、BET、XRD、FT-IR、SEM等方法對其進行表征,考察碳化溫度、磺化溫度、模板劑用量對催化劑表面-SO3H數(shù)量、比表面積和孔徑的影響,并將其用于大豆油與甲醇的酯交換反應(yīng),結(jié)果表明:制備催化劑的適宜條件為碳化溫度400℃、磺化溫度170℃、m二氧化硅:m蔗糖=1:2;大豆油與甲醇酯交換反應(yīng)的最佳條件為醇油摩爾比30:1、反應(yīng)時間4h、催化劑用量8%,生物柴油收率最高達95.94%。在此反應(yīng)條件下,考察催化劑的耐酸性,當(dāng)油脂中脂肪酸含量高達15%時,酯交換轉(zhuǎn)化率可達到90.87%,脂肪酸轉(zhuǎn)化率達到99%,為高酸值油脂一步法制備生物柴油奠定了基礎(chǔ)。(2)在低溫、常壓下,考察介孔碳基固體酸催化劑催化油酸的酯化反應(yīng),在油醇摩爾比1:15、反應(yīng)溫度70℃、反應(yīng)時間3h、催化劑用量8%的條件下,酯化轉(zhuǎn)化率達到最大97.47%,催化劑重復(fù)使用5次,轉(zhuǎn)化率依然達到96%以上;并對介孔碳基固體酸催化酯化反應(yīng)動力學(xué)進行初步研究,反應(yīng)級數(shù)1.38,表觀活化能為58.7kJ/mol。(3)以二氧化硅和氫氧化鋰為原料,通過沉淀法制備硅酸鋰固體堿催化劑,采用SEM、XRD等手段對催化劑進行表征,將制備的催化劑用于催化大豆油與甲醇的酯交換反應(yīng),通過單因素優(yōu)化法考察最佳反應(yīng)條件:醇油摩爾比12:1、催化劑用量6%、反應(yīng)溫度65℃、反應(yīng)時間2h,生物柴油轉(zhuǎn)化率達到99.64%,催化效果與液體堿相當(dāng),可以用于高酸值油脂制備生物柴油的第二步催化反應(yīng),也可用于一般油脂一步酯交換法制備生物柴油。催化劑重復(fù)使用5次后,轉(zhuǎn)化率達到96.36%,表現(xiàn)出非常好的穩(wěn)定。
[Abstract]:With the acceleration of industrialization and modernization in the world, the demand for petroleum resources is increasing. However, the extensive use of fossil fuels will bring about energy crisis and environmental problems. Therefore, more and more attention has been paid to the search for new alternative energy sources. Biodiesel is considered to be the best substitute for fossil fuels because of its renewable, green and biodegradable properties. Replacing pure vegetable cooking oil with high acid oil can reduce the production cost and improve the competitiveness of biodiesel. The process of preparing biodiesel from high acid oil can be divided into two steps: preesterification and transesterification. Most of the catalysts are homogenous acid-base, but homogeneous acid-base catalysts bring about the product is difficult to separate, the recovery of catalyst is difficult, the washing produces a large amount of waste water, and can not be continuously produced, and so on. In order to solve these problems, In this paper, two kinds of solid catalysts (mesoporous carbon-based solid acid and lithium silicate solid base) and their applications in the preparation of biodiesel with high acid value oil were systematically studied. (1) Sucrose was used as carbon source and SiO-2 as template. The mesoporous carbon-based solid acid catalyst was prepared by carbonation and sulfonation method. It was characterized by acid-base titration method. The effects of carbonation temperature, sulfonation temperature and the amount of template on the amount of -SO3H on the surface, specific surface area and pore size of the catalyst were investigated. It was used in the transesterification of soybean oil and methanol. The results showed that the suitable conditions for the preparation of the catalyst were carbonization temperature 400 鈩，

本文編號：2251189