滇池蓝藻在亚/超临界乙醇中热化学催化液化制备生物油及其特性

在高压反应釜中,以亚/超临界乙醇为液化介质、以SO42-/ZrO2为催化剂催化液化滇池蓝藻制备生物油,考察了反应温度、反应时间、催化剂用量、料液比等对蓝藻液化效果的影响. 正交实验表明,反应温度270℃、反应时间40 min、催化剂SO42-/ZrO2加入量为蓝藻质量的2%、蓝藻与乙醇比为1:15 g/mL是最佳的条件,在此条件下液化率为87.46%,油产率为63.32%. 分析了生物油的特性和组分,生物油是一种组成复杂的有机混合物,其主要成分为十六烷酸乙酯.     

生物油提质用催化剂研究进展

文章综述了生物油提质中的催化剂应用情况,包括第VIII族元素催化剂、裂解催化剂、固体酸碱催化剂。阐述了催化剂应用中的问题,最后就其发展和前景进行了展望和评述。     

生物油提质改性研究进展

从乳化、催化加氢、催化裂解、催化酯化、重整制氢、萃取和膜分离等7个方面阐述了生物油的提质改性技术及其研究进展。认为生物油低热值、强酸性和高粘度等特性影响了其广泛应用,因此必须对生物油进行提质改性,除了从工艺过程方面入手外,选择合适的乳化剂、催化剂、萃取剂或半透膜以提高分离效果、降低成本并易于实现工业化将会是今后的重点研究方向。     

超临界乙醇技术原理研究与运用进展

综述了超临界乙醇在制备生物柴油中的主要技术,分析了在酯交换反应、酯化反应、液化反应制生物油以及生物油加氢升级中的原理及应用。研究表明,超临界乙醇的酯交换反应过程由三个连续可逆的反应组成,水和CO_2均能提高反应速率。在酯化过程中,乙醇、酸的浓度对过程存在显著影响,此外,动力学模型表明酸存在催化效应,因此水解及油酸本身存在酸催化效应及自催化作用。超临界乙醇被广泛用于生物质的液化过程,过程主要存在:(1)生物质裂解;(2)油份重整(涉及酯交换及酯化反应等);(3)结焦或结聚;(4)小分子组分气化;及(5)气体间相互反应等典型反应等;且升高温度有利于液化;液化过程中醇与水表现出协同作用。此外,在生物油的加氢升级过程中,超临界乙醇不仅作为一种良好的反应介质,也作为反应物与生物油中的酸类物质发生酯化反应,降低生物油的酸度,提高生物油的热值。因此,超临界乙醇在生物燃料的制备与升级中具有良好的应用前景。     

超临界流体技术制备Ru/C催化剂的研究

以活性炭为载体、氯化钌为活性前驱体,采用超临界CO2流体沉积技术制备了Ru/C催化剂,用葡萄糖加氢生产山梨醇反应考察催化剂的催化活性.用正交实验考察了温度、CO2的量和还原剂KBH4的量等因素对制备Ru/C催化剂催化活性的影响规律;用红外光谱(IR)和扫描电镜(SEM)对Ru/C催化剂样品进行了结构表征.结果表明:制备...     

生物油的特性、提质及应用

生物油是一种由生物质直接转化为液体燃料的新型可再生能源,具有产量大、可储存和碳循环等优点。综述了国内外生物油的物性特点、提质以及应用等研究进展。结果表明,生物油作为化石燃料的替代燃油存在很大优势,但其热值低、腐蚀性强等缺陷仍需进一步改进。     

生物质催化热解制油及油品改性提质研究进展

基于国家碳中和背景,生物质作为一种重要的可再生资源,其有效利用至关重要。生物质热解制油具有规模化潜力,成为目前生物质利用的主要方式。生物质热解技术按照液化方式不同分为直接液化和间接液化,但生物质直接液化所得生物油组分不稳定,间接液化所得生物油品质取决于反应器型式、反应温度及催化剂类型等,不同制备方法的生物油品质差别较大,生物油改性提质成为其实际应用的必要条件。归纳比较了生物质热解过程中提高生物油品质的催化剂类型,着重综述了原生物油分离为轻质组分和重质组分后分别改性提质的技术路线,可转化为燃气、燃油甚至化学品,实现生物油的高值化。针对轻质油组分的改性方法有水蒸气重整制氢、催化裂解、加氢脱氧、催化酯化等,催化剂类型以分子筛及贵金属为主;而重质油组分水含量低、黏性大,相关提质研究较少,目前报道以加氢、裂化、酯化、添加溶剂、气化为主。生物油提质改性方法中,催化剂、氢源、耗能是限制其规模化、工业化应用的主要原因,降低催化剂成本及提高催化剂寿命、减少氢源使用或利用低成本氢源、简化工艺及降低反应温度是生物油提质技术发展方向。     

生物油电催化加氢提质技术研究进展

生物油是一种可再生的碳中和有机资源,在液体燃料和高值化学品生产中显示出较大的潜力,对其大规模利用有助于实现碳中和目标。生物油因其固有的腐蚀性和化学不稳定性而需要提质以提高其应用价值。电催化加氢能够在常温常压下实现生物油加氢提质,该方法反应条件温和、操作简单、能源效率高,具有碳中和属性,为生物油提质提供了新的选择。综述了近年来生物油电催化加氢的研究进展,分析了不同生物油模型化合物在电催化加氢过程中的作用机理。讨论了真实生物油样品的电催化加氢实例,以证明电催化应用于生物油提质的可行性。最后,针对生物油电催化加氢提质技术面临的困难和挑战,提出了该领域未来的研究方向和重点,并展望了生物油电催化加氢提质工业化应用的前景。     

花生壳发酵生产生物乙醇可行性研究

研究以花生壳为原料,采用超临界水一步法获得可发酵糖液,并通过混合菌种将可发酵糖液转化为生物乙醇的工艺方法。不仅使农业废弃物得到综合利用,同时,也获得了良好的经济效益和环境效益。     

亚/超临界乙醇条件下杨木屑与甘油共液化研究

以60～80目的杨木屑为原料,甘油为液化剂,酸为催化剂,基于超临界乙醇条件下对杨木屑进行液化制备生物重油。实验结果表明:以2.5%硫酸为催化剂,在甘油/乙醇/木屑质量比为5∶10∶2条件下,250℃反应1 h,木屑的转化率可达98%。此液化油含水量为3.04%(wt),运动黏度为524 mm2/s,酸值为2.1 mg KOH/g,羟值为846 mg KOH/g。对液化油进行IR、GPC和GC-MS分析的结果显示,液化油含有大量的羟基物质,平均相对分子质量为811,并且含有4-羰基戊酸丁酯、三乙基甘油醚等聚酯/聚醚类多元醇。     

Ball milling promoted direct liquefaction of lignocellulosic biomass in supercritical ethanol

In the present work, ball milling was applied for the pretreatment of lignocellulose to obtain high conversion and bio-oil yield in supercritical ethanol. Ball milling substantially decreased the crystallinity and particle size of lignocellulose, thereby improving its accessibility in ethanol solvent. An increased bio-oil yield of 59.2% was obtained for the ball milled camphorwood sawdust at 300°C, compared with 39.6% for the original lignocellulose. Decreased crystallinity significantly benefited the conversion of the cellulose component from 60.8% to 91.7%, and decreased particle size was beneficial for the conversion of all components. The obtained bio-oil had a high phenolic content, as analyzed by gas chromatography-mass spectrometry. Methoxylation and retro-aldol condensation were observed during alcoholysis, and the reaction pathways of lignocellulose in supercritical ethanol were attributed to the action of free radicals.     

A review on catalytic & non-catalytic bio-oil upgrading in supercritical fluids

This review article summarizes the key published research on the topic of bio-oil upgrading using catalytic and non-catalytic supercritical fluid(SCF)conditions.The precious metal catalysts Pd,Ru and Pt on various supports are frequently chosen for catalytic bio-oil upgrading in SCFs.This is reportedly due to their favourable catalytic activity during the process including hydrotreating,hydrocracking,and esterification,which leads to improvements in liquid yield,heating value,and pH of the upgraded bio-oil.Due to the costs associated with precious metal catalysts,some researchers have opted for non-precious metal catalysts such as acidic HZSM-5 which can promote esterification in supercritical ethanol.On the other hand,SCFs have been effectively used to upgrade crude bio-oil without a catalyst.Supercritical methanol,ethanol,and water are most commonly used and demonstrate catalyst like activities such as facilitating esterification reactions and reducing solid yield by alcoholysis and hydrolysis,respectively.     

Upgrading of bio-oil in supercritical ethanol: Catalysts screening,solvent recovery and catalyst stability study

Supercritical upgrading of bio-oil is an effective method to upgrade bio-oil. In this paper, upgrading of bio-oil was carried out in supercritical ethanol with the aim of catalyst selection, reducing solvent consumption and catalyst stability study. Compared with Ru/HZSM-5, C-supported catalysts (Pt/C, Pd/C, and Ru/C) gave better catalytic performance. Over the C-supported catalysts, the heating value increased from 21.45 MJ/kg to about 30 MJ/kg and the pH value increased from 3.13 to about 5.5. The relative content of desired products reached as high as 80% over Ru/C. The ratio of ethanol to bio-oil was further reduced to about 1:1 by solvent recovery and reutilization. The relative content of desired products particularly that of esters increased with the recovered solvent. Catalytic stability study of Ru/C showed that the relative content of desired products decreased gradually with the number of catalyst recycle times while the consumption of hydrogen decreased mainly in the first recycle. Coke deposition and sintering of metal particles were the main reasons for the deactivation of Ru/C.     

Production of renewable fuels by blending bio-oil with alcohols and upgrading under supercritical conditions

The work studied a non-catalytic upgrading of fast pyrolysis bio-oil by blending under supercritical conditions using methanol, ethanol and isopropanol as solvent and hydrogen donor. Characterisation of the bio-oil and the upgraded bio-oils was carried out including moisture content, elemental content, pH, heating value, gas chromatography-mass spectrometry (GCMS), Fourier transform infrared radiation, ¹³C nuclear magnetic resonance spectroscopy, and thermogravimetric analysis to evaluate the effects of blending and supercritical reactions. The GCMS analysis indicated that the supercritical methanol reaction removed the acids in the bio-oil consequently the pH increased from 2.39 in the crude bio-oil to 4.04 after the supercritical methanol reaction. The ester contents increased by 87.49% after the supercritical methanol reaction indicating ester formation could be the major deacidification mechanism for reducing the acidity of the bio-oil and improving its pH value. Simply blending crude bio-oil with isopropanol was effective in increasing the C and H content, reducing the O content and increasing the heating value to 27.55 from 17.51 MJ·kg^‒1 in the crude bio-oil. After the supercritical isopropanol reaction, the heating value of the liquid product slightly further increased to 28.85 MJ·kg^‒1.     

超临界乙醇萃取苯酚的实验研究

以乙醇为超临界溶剂,采用恒容升温法研究了超临界乙醇对苯酚的萃取效果,探讨了温度和压力对萃取效果的影响。结果表明,在萃取温度为270~275℃,萃取压力为13 MPa左右时,萃取效果明显,萃取率达62%以上,苯酚在超临界乙醇中的质量浓度为0.015 657 g/mL,实验效果明显。研究得出,温度与压力对固体物质的超临界溶解度具有明显的选择调节性。     

小球藻热解油在Ni-Cu/ZrO2催化剂上的加氢脱氧

在小型固定床反应器中以Ni-Cu/ZrO₂为催化剂,对小球藻热解油进行催化加氢脱氧,以改善生物油性能。利用XRD、H₂-TPR、TG、NH₃-TPD等技术对催化剂进行了结构表征。结果表明,Cu的加入有效促进了Ni-Cu/ZrO₂催化剂活性相的表面分散,提高了该催化剂对小球藻热解油加氢脱氧反应的催化活性。在2 MPa、350 ℃反应条件下,随Cu/Ni的增大,Ni-Cu/ZrO₂的催化活性先升高后降低,Cu/Ni质量比为0.40时的催化性能最好,连续运行3 h后所得精制生物油脱氧率达82.0%。Ni-Cu/ZrO₂催化剂在反应过程中,表面结焦少,活性粒子及催化剂性能稳定,连续运行24 h后所得精制生物油脱氧率依然维持在77.0%以上。小球藻热解油经催化加氢脱氧所得的精制生物油,低位热值由31.5 MJ·kg^-1提高至35.0 MJ·kg^-1,40℃运动黏度由20.5 mm²·s^-1降至9.5 mm²·s^-1,且油品中水分更易于脱除。精制生物油中高级脂肪酸的含量减少,油品稳定性大幅提高。     

超临界乙醇萃取萘的实验研究

采用恒容升温法研究了超临界乙醇萃取煤焦油重要组分萘的效果,讨论了萃取温度和压力对萃取效果的影响.结果表明,在温度为270℃、压力为13MPa时,萘的超临界浓度为1.739×10^-2g/mL、萃取率为66.20％.     

加压和超临界条件下乙醇分子的缔合

引言 在化学和化工领域,分子扩散系数是过程设计和装置优化所需的基本数据之一[1].乙醇作为一种高效绿色溶剂,具有良好的溶剂性能和比较温和的临界温度、临界压力(Tc=514.3 K,pc=6.38MPa),在食品、医药和化工等领域有巨大的应用空间[2].     

Depolymerization of poly(ethylene terephthalate) wastes using ethanol and ethanol/water in supercritical conditions

Chemical recycling of poly(ethylene terephthalate) (PET) in supercritical ethanol has been investigated. In the presence of water, under supercritical conditions (temperature and pressure above 516 K and 6,384 kPa, respectively) excess ethanol reacts with PET to form diethyl terephthalate (DET) as the main product. A laboratory‐made 0.1 L ‐batch reactor was used at 528 K under pressures from 7,600 and 11,600 kPa. After the required reaction times, the reaction products were analyzed by reverse phase high pressure liquid chromatography and nuclear magnetic resonance. It was found that PET is completely depolymerized into monomers in about 5 h. The influences of water, pressure, ethanol/PET weight ratio, PET sources, as well as depolymerization time were investigated. Maximum DET recovery yield was 98.5%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2009–2016, 2006     

加压或超临界溶剂对乙醇发酵和在线萃取分离的影响

压缩或超临界流体作为良好的萃取溶剂,在食品加工与保藏、制药和生物材料加工等领域有广阔的应用前景。在简要论述了压缩或超临界流体对微生物存活与催化活性影响的基础上,详细综述了近年来采用超临界溶剂进行乙醇发酵与在线萃取分离过程取得的新进展,特别是装置结构设计和过程优化方面的新成果。最后探讨了实现过程规模化需要深入开展的关键性问题。