藻类液化生物油的催化脱氧改质进展

含氧过多是限制藻类液化油实际应用的最大障碍,高含氧量意味着热值低、稳定性差、酸性强等,因此必须经过脱氧改质才能使其转化为高品位燃油。结合最新研究进展,首先选取藻类液化油中具有代表性的成分脂肪酸为模型化合物,总结了催化剂组成和反应气氛对脂肪酸脱氧机理及反应活性的影响。其次对目前国内外藻类液化原油及其轻馏分的催化脱氧改质研究现状进行综述。最后指出藻类液化生物油催化改质存在的问题,并对改进方法及未来的发展进行了展望。     

有机质亚/超临界水液化研究进展

亚/超临界水具有独特理化特性,如能高效溶解、快速传质及有效打断高分子碳链,使得亚/超临界水液化成为有机质制油的高效手段。本文总结了典型有机质如纤维素、木质素、藻类、煤及聚合物亚/超临界水液化的过程,概述了其亚/超临界水液化特点及产物油特征,并阐明了液化过程机理,总结了裂解/热解反应、杂原子脱出反应、缩聚反应等关键反应;针对液化油升级及脱除杂质技术,总结了均相催化剂如H3PO4、K2CO3、KOH等的催化特点及机理,分析了非均相催化剂如Ni、Mo、Pt等提高油品质的催化技术特点及目前对杂元素氧、氮、硫等脱氧脱除技术研究概况。最后对亚/超临界水液化初油存在品质不高、含多种杂原子等问题及如何提高初油、脱除杂原子技术研究进行了总结,并展望了工业放大过程中的瓶颈与策略,为未来工业运用提供基础。     

小球藻热解油在Ni-Cu/ZrO_2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。     

催化裂化汽油改质降烯烃反应规律及反应热

利用催化裂化催化剂在小型固定流化床实验装置上对催化裂化汽油催化改质降烯烃过程的反应规律进行了实验研究,详细考察了反应温度、剂油比和重时空速对产物收率和汽油辛烷值的影响,得到了催化裂化汽油改质过程的最佳实验操作条件：反应温度为400～430℃,剂油比为7左右,重时空速为20～30 h-1。在此基础上,计算了汽油改质过程的反应热,分析了反应条件对反应热的影响,揭示了反应热的变化规律。结果表明,低温改质为放热过程,高温改质为吸热过程。改质条件对反应热影响的强弱顺序为反应温度>剂油比>重时空速。     

水热催化液化制备生物油研究

生物质水热液化技术是最具有发展前景的生物质液化技术之一,可以将生物质直接转化为高品位气态、液态和固态产物。生物质液化过程中催化剂可以适度地降低反应温度和反应压力,加快反应速率,增加液化油的生成量,并且具有改变产物组成从而抑制焦炭的形成、提高液化油的品质等功效,本文主要对近年来水热液化制备生物油过程中各类催化剂进行了综述,着重介绍了均相催化与非均相催化对生物油性质的影响及使用情况并探讨了其催化机理,指出研究催化剂对水热液化具有重要的意义。     

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。     

流化催化裂化汽油改质和增产低碳烯烃的研究

采用GL型催化剂,在小型固定流化床实验装置上考察了反应温度、剂油比、空速和水油比等操作条件对流化催化裂化(FCC)汽油催化改质汽油的产品分布、低碳烯烃(丁烯、丙烯和乙烯)产率和族组成的影响。实验结果表明,在一定反应条件下,FCC汽油通过催化改质可以降低烯烃含量,提高芳烃含量和辛烷值,在满足新汽油标准的同时提高了低碳烯烃的产率。此外,较高的反应温度、剂油比和水油比以及较低的空速有利于FCC汽油催化改质和增产低碳烯烃。     

生物质油改性方法研究进展

生物质快速裂解液体产物生物油(简称生物质油),具有水含量高、氧含量高、热值低、粘度大、热不稳定和化学不稳定等特性,在一定程度上影响了其广泛应用,因此必须通过精制改善其品质.按生物质快速裂解的反应过程,将提高生物质油品质的方法归纳为三类:第一类(反应前),快速裂解反应前,原料脱水和脱碱金属处理;第二类(反应中),快速裂解反应过程中,生物质油蒸汽不经冷凝直接改质;第三类(反应后),快速裂解反应完成后,采用对收集到的生物质油催化加氢、催化裂解、催化酯化、乳化、添加溶剂或添加抗氧化剂等方法进行改质.     

催化裂化汽油二次反应过程中反应热的变化

根据热力学理论,通过产物和反应物的生成焓计算了催化裂化汽油在降烯烃改质以及催化裂解过程中的反应热,并根据不同反应过程的实验结果考察了反应温度、停留时间和剂油比对反应热的影响。计算结果表明,催化裂化汽油降烯烃改质和催化裂解过程都是吸热反应体系,降烯烃改质过程的反应热为80～150 kJ·kg^-1,催化裂解过程的反应热为370～620 kJ·kg^-1;反应条件对反应热的影响通过改变反应物的转化率和产物分布实现。在实验条件范围内,随着反应温度的升高、剂油比的增大和停留时间的延长,反应热逐渐增大;当剂油比增大到一定程度时,反应热随剂油比的增加趋势变缓。     

加压水蒸气下年轻煤脱氧改质的研究

年轻煤是煤液化的良好原料 ,但它的氧含量高增加了煤液化过程中无用的氢耗 ,对这些煤进行脱氧改质有重要的意义 .选择了四种年轻煤——霍林河、小龙潭、义马和神华煤在高压釜内水蒸气气氛下进行了脱氧改质的研究 .结果表明 ,处理后煤样的氧含量和含氧官能团降低显著 ,氧的脱除率最高达到了 2 0 .7% .此外 ,煤质还有一些其他的变化 ,如热值和碳含量有所提高 ,最高内在水分和挥发分降低 ,表明煤阶有所提高 .对煤中的总酸性基、羧基和酚羟基的化学分析显示 ,脱氧改质后煤样的羧基、酚羟基等含氧官能团明显降低 ,羧基和酚羟基的最高脱除率分别达到了78.5 %和 31 .3% ,达到了脱氧改质的目的 .     

生物质油加氢脱氧精制研究进展

随着石油能源渐趋匮乏,生物质高温裂解制备生物质油备受关注。而生物质油中氧含量高达40%,这将影响生物质油的稳定性、极性、热值、粘度和酸性等,应必须对其进行加氢脱氧精制处理。文中介绍了裂解生物质油的组成分布和特点,阐述了裂解生物质油加氢脱氧精制的反应过程和影响因素。     

Upgrading of biofuel by the catalytic deoxygenation of biomass

Biomass can be used to produce biofuels, such as bio-oil and bio-diesel, by a range of methods. Biofuels, however, have a high oxygen content, which deteriorates the biofuel quality. Therefore, the upgrading of biofuels via catalytic deoxygenation is necessary. This paper reviews the recent advances of the catalytic deoxygenation of biomass. Catalytic cracking of bio-oil is a promising method to enhance the quality of bio-oil. Microporous zeolites, mesoporous zeolites and metal oxide catalysts have been investigated for the catalytic cracking of biomass. On the other hand, it is important to develop methods to reduce catalyst coking and enhance the lifetime of the catalyst. In addition, an examination of the effects of the process parameters is very important for optimizing the composition of the product. The catalytic upgrading of triglycerides to hydrocarbon-based fuels is carried out in two ways. Hydrodeoxygenation (HDO) was introduced to remove oxygen atoms from the triglycerides in the form of H₂O by hydrogenation. HDO produced hydrogenated biodiesel because the catalysts and process were based mainly on well-established technology, hydrodesulfurization. Many refineries and companies have attempted to develop and commercialize the HDO process. On the other hand, the consumption of huge amounts of hydrogen is a major problem hindering the wide-spread use of HDO process. To solve the hydrogen problem, deoxygenation with the minimum use of hydrogen was recently proposed. Precious metal-based catalysts showed reasonable activity for the deoxygenation of reagent-grade fatty acids with a batch-mode reaction. On the other hand, the continuous production of hydrocarbon in a fixed-bed showed that the initial catalytic activity decreases gradually due to coke deposition. The catalytic activity for deoxygenation needs to be maintained to achieve the widespread production of hydrocarbon-based fuels with a biological origin.     

Fuel properties of bio-oil/bio-diesel mixture characterized by TG, FTIR and 1H NMR

There has been an increasing interest in alternative fuels made from biomass which is abundant and renewable. Bio-oil and bio-diesel seem to be such promising liquid fuels. Bio-oil produced by fast pyrolysis of biomass is highly viscous, acidic, and has high water content. To overcome these problems as a fuel, a method of emulsifying bio-oil with bio-diesel was performed in the previous paper, and a stable mixture of bio-oil and bio-diesel was successfully prepared. In this paper, several properties of the mixture are discussed by using TG, FTIR and ¹H NMR. The results show us that, compared with crude bio-oil, some properties of bio-oil/bio-diesel mixture such as water content, acid number, viscosity are much improved. The thermal decomposition of the mixture under air/nitrogen is shown using a thermogravimetric analyzer (TGA). Further information about the functional groups is exhibited through Fourier Transform infrared spectrometer (FTIR) and nuclear magnetic spectroscopy (NMR).     

生物质热解制备高品质生物油研究进展

生物质热解制备生物油是能源富集的有效途径,是实现碳闭路循环的重要方式,作为一种环境友好型技术受到广泛关注和研究。然而,生物质热解反应过程复杂,生成的生物油热值低、含氧量高及强酸性等特点,制约了生物油的分离提纯、制备合成气以及燃烧等方面的应用,生物油品质的提升迫在眉睫。本文从生物质三组分、原料预处理、反应参数、催化剂、反应器等方面综述了影响生物油品质的主要因素,分析了生物油的特点,不同预处理下生物质特性的变化与生物油的关系,催化剂参与的热解行为对提升生物油品质的导向作用以及常用生物质热解反应器的特点,并对影响生物油品质的主要因素进行了总结。最后,针对影响制备高品质生物油的诸多因素提出建议,以期为制备高品质生物油提供参考和借鉴。     

Deactivating species in the transformation of crude bio-oil with methanol into hydrocarbons on a HZSM-5 catalyst

A study has been carried out by using different techniques (TPO, FTIR, Raman, ¹³C NMR, GC/MS of the coke dissolved in CH₂Cl₂) on the nature of the coke deposited on a HZSM-5 catalyst modified with Ni in the transformation of the crude bio-oil obtained by flash pyrolysis of lignocellulosic biomass (pine sawdust) into hydrocarbons. The reaction system has two steps in-line. In the first one, the components of crude bio-oil derived from the pyrolysis of biomass lignin are polymerized at 400 °C. In the second one, the remaining volatile oxygenates are transformed into hydrocarbons in a fluidized bed catalytic reactor at 450 °C. The reaction has been carried out with different bio-oil/methanol mass ratios in the feed (from 100/0 to 0/100). Co-feeding methanol significantly attenuates coke deposition, and the nature of the coke components varies according to the bio-oil/methanol ratio in the feed. When bio-oil is co-fed, the coke deposited on the catalyst has a significant content of oxygenates and oxo-aromatics and consists of two fractions, identified by temperature programmed oxidation, corresponding to external and internal coke in the zeolite crystals. The fraction of external coke is soluble in CH₂Cl₂, with a high content of oxygenates and oxo-aromatics, and is generated by polymerization of products derived from biomass lignin pyrolysis activated by the zeolite acid sites. The fraction of coke retained within the zeolite crystals is partially insoluble and is formed by several routes: from the intermediates in the transformation of both methanol and bio-oil oxygenates into hydrocarbons; by evolution of the other coke fraction; from the hydrocarbons (with high aromatics content) in the reaction medium.     

碱土金属氧化物基催化剂催化热解生物质研究进展

快速热解是生物质高效转化利用的重要方法之一,然而其目标产物生物油因含氧量高、组分复杂等不足而难以直接利用。通过在热解体系中引入碱土金属氧化物基催化剂,可以将热解产物中的氧元素以CO₂和H₂O等方式脱除,从而实现生物油品质的提升。总结了典型碱土金属氧化物基催化剂对生物质催化热解过程中发生的酮基化、羟醛缩合、开环和侧链断裂反应及机理,讨论了催化剂类型（CaO、MgO、基于碱土金属氧化物的分子筛和活性炭等）、生物质原料、温度、催化剂用量、停留时间、催化方式、催化剂失活等因素对生物油产率与品质的影响,并对生物质催化热解制备高品质生物油及其应用进行了展望。     

Recent advances in the catalytic hydrodeoxygenation of bio-oil

Owing to the increasing interest in alternative energy, there is a focus on bio-oil production from biomass because it is an abundant and renewable energy source. Among the various kinds of biomass conversion technologies, pyrolysis has been investigated widely to produce bio-oil. However, the direct use of bio-oil is difficult because of its poor quality due to the large amounts of oxygen-containing compounds, such as acids, ketones, and esters. Therefore, an additional suitable upgrading process for bio-oil is required. Hydrodeoxygenation (HDO) is considered effective for the deoxygenation of bio-oil. This paper reviews the recent progress in the catalytic HDO of bio-oil. In addition, the effects of the solvent and catalyst applied to the HDO of bio-oil are reviewed intensively together with a discussion of the deactivation behavior of the catalyst during HDO.     

Hydrothermal liquefaction of wheat straw in hot compressed water and subcritical water–alcohol mixtures

Hydrothermal liquefaction of lignocellulosic biomass (wheat straw) into bio-oil has been investigated under subcritical conditions (temperature up to 350 °C, pressure up to 200 bar) in water and water–alcohol mixtures using ethanol and isopropanol in a continuously operated tubular reactor. The effect of different reaction parameters such as temperature, pressure and water–alcohol ratio on the biomass conversion, cracking products yield and the higher heating value (HHV) of the received bio-oil was studied. The water–ethanol mixture was found to be a very reactive medium showing a complete biomass conversion and >30 wt% yield of high caloric oil (HCO). A maximum HHV of 28 MJ/kg for HCO was achieved. In addition, Ru (5 wt%) on H-Beta support was used as catalyst in a run with hydrogen in the feed showing deeper deoxygenation of reaction intermediates and highest HHV of the product oil (30 MJ/kg). This work demonstrated the usability of water–ethanol mixtures for an effective depolymerization of lignocellulosic biomass to bio-oils under subcritical reaction conditions with more than doubled HHV compared to the feedstock, in particular using a catalyst and the presence of hydrogen for further deoxygenation.     

生物质转化及生物质油精制的研究进展

目前,生物质热解和生物质液化是两种有效的生物质转化技术,其转化所得生物质油有望替代化石燃料。但是生物质油的高含氧量、低热值和化学不稳定性影响其广泛应用,对生物质油进行精制以改善生物质油品质,是当前研究的热点。介绍了生物质常用的转化技术——生物质热解和生物质液化,并比较了这两种工艺所得生物质油的特性,评述了油品精制工艺,为生物质油利用提供参考。     

生物油的组成和提质研究的进展

生物油即生物质裂解油,具有原料充足、可再生、价格低廉、提质后作为液体燃料利用热值高和污染较小等优点,因而生物油提质技术成为能源化工领域研究的热点之一。了解生物油的组成可以提供生物油提质的重要信息。评述了生物油的组成和提质研究的进展,总结了存在的问题,预测了今后的发展方向。