生物原油炼制： 副产物内循环及水热自催化

利用高温高压条件模拟石油生成的生物质水热液化技术可用于制备生物原油,以替代日益枯竭的石油资源,然而副产物处置问题制约了其可持续发展。解决该问题的方法首先是通过水热定向催化调控减少副产物,然后集成各种技术将副产物尽可能原位资源化。基于此并依据生物炼制的思想,本文对一种集成几种水热技术炼制生物原油的模式进行了讨论。依据生物质水热液化副产物的特性,通过对固体产物水热合成制备催化剂、水相产物回用产生有机酸、气体产物分离或彻底氧化后水热还原生产有机酸等,可实现副产物内循环并强化自催化生成生物原油。指出该模式符合绿色化工的理念,对于加快规模化生产可替代石油的生物原油、缓解能源危机具有重要的参考意义。     

木质纤维水热液化研究进展

水热液化是木质纤维生物质的热转化方法之一,其因以水作为溶剂被认为是环境友好型技术。本文综述了木质纤维生物质水热液化的研究进展,对木质纤维生物质的水热液化产物分析策略进行概述。分析了纤维素、半纤维素和木质素等木质纤维生物质组分的水热液化机理以及水热液化产物组成和分布。讨论了反应温度、反应时间、催化剂和助溶剂等对木质纤维水热液化的影响,重点介绍了生物油、不凝性气体和固体残渣等液化产物的表征手段。最后对未来木质纤维水热液化发展方向提出了建议。     

胜利煤与秸秆共液化的研究

选用胜利褐煤和玉米秸秆为原料,在高压反应釜内,对其共液化反应性进行了研究。利用索氏抽提对液相产物进行了分离,系统地考察了反应温度、原料配比、初始氢压和反应时间对胜利煤和秸秆共液化的影响。研究结果表明:秸秆能够有效地促进胜利煤的转化,提高油产率。在反应温度420℃、初始氢压9MPa、秸秆/胜利煤质量配比=2/8和反应时间60min时,胜利煤和秸秆共液化的转化率和油产率分别为99.74%、65.30%。     

水热法处理浮萍生物质制取生物油

水热液化法是生物质一种行之有效的热化学转化方法。生物质水热液化以生物质为原料,利用水作为反应介质,通过热解液化制取生物原油。与快速热解液化技术相比水热液化不需对生物质进行烘干预处理,操作条件相对温和,对设备要求相对较低,易于实现工业化,且液化所生成的生物原油含氧量低、热值高。此外,用水热液化法直接处理浮萍不但能将其油份转化为生物油,而且其中的淀粉以及其它有机成分也可一并转化。本研究采用间歇式不锈钢反应釜,在水热环境下,系统考察了温度(270～380℃)、反应时间(10～120min),浮萍添加量(0.5～5.5g),催化剂(K2CO3)添加量(0～50%)等因素对浮萍液化产物分布的影响规律。研究发现,温度、反应时间、反应物浓度以及催化剂4个因素均对液化产物分布用影响,且K2CO3的存在不利于浮萍的水热液化。在温度为350℃,反应时间为30min,浮萍添加量为3.5g时,浮萍可基本完全转化,此时所得生物油产率最大(19.76%,质量分数)。在所考查的实验条件下,所得生物油的热值为32～35 MJ/kg。与原料相比,液化油中的C、H以及N的含量明显升高,O的含量明显下降,H/C比和S的含量略微有所下降。水热液化所得生物油中的主要成分为酮类及其衍生物、醇、含氮杂环、饱和脂肪酸以及饱和和不饱和的碳氢化合物。     

秸秆与兖州煤共液化反应条件的研究

在高压反应釜内,以四氢萘为供氢溶剂,Fe2O3＋S为催化剂,研究了温度、反应时间、初始氢压、配比对兖州煤与秸秆共液化的影响。结果表明,提高反应温度,转化率、油产率增加;延长反应时间对转化率、油产率的影响较小;升高初始氢压,转化率、油产率刚开始增加,6 MPa以后增幅趋缓;在m（秸秆）∶m（兖州煤）=0.5∶9.5时,共液化的油产率为60.45%,比兖州煤单独液化的油产率提高了4.17%;在m（兖州煤）∶m（秸秆）=9.5∶0.5,440℃,8 MPa,90 min的条件下,共液化转化率和油产率达到最大,分别为83.58%和63.1%。     

玉米秸秆多羟基醇液化研究

研究了玉米秸秆在多羟基醇中的液化反应,结果表明液化剂用量、反应温度、反应时间以及催化剂用量等条件对玉米秸秆液化反应有较大的影响。以聚乙二醇和甘油的混合物为液化剂,在温度为160℃、时间为30 min、液化剂用量为玉米秸秆质量的4.5倍、浓硫酸用量为液化剂用量的3.25%时,液化率可达到90%,所得到的玉米秸秆液化产物羟值为380 mg/g,黏度为353 mPa·s。同时通过红外光谱分析了玉米秸秆液化的有关机理。     

超/亚临界水两步法水解玉米秸秆制备还原糖

以玉米秸秆为原料,采用两种间歇式反应器,对其在超/亚临界水条件下的水解行为进行研究,重点考察了反应温度、反应时间对还原糖产率和液化率的影响。设计了亚临界低温段水解+超临界高温段水解两步法水解生物质的工艺路线,并与超临界一步法水解工艺进行比较。结果表明,对玉米秸秆进行低温段水解,在固液比1∶100、190℃、40 min条件下获得最大还原糖产率为24%;将低温段水解残渣作为高温段水解的原料,在380℃、20 s条件下获得最大还原糖产率为34%。相同条件下,用超临界一步法直接对玉米秸秆进行水解,获得最大还原糖产率为41%。超/亚临界水两步法水解玉米秸秆工艺所获得的还原糖总产率为58%,比超临界一步法水解工艺的还原糖产率提高了17%。     

亚/超临界乙醇-水体系中磺化碳固体酸催化液化玉米秸秆

以微晶纤维素为原料,通过炭化和磺化制备了一种磺化碳固体酸催化剂,利用红外光谱和扫描电镜等方法对其进行了表征。研究了该催化剂在亚/超临界乙醇-水溶剂中针对玉米秸秆的催化液化性能,考察了反应温度、催化剂用量、乙醇/水体积比等因素对生物油得率的影响。结果表明:在反应温度320℃、催化剂用量为原料质量分数的6%、乙醇/水体积比为1/1、反应时间3 h条件下,生物油得率可达52%。     

磷钨酸催化液化玉米秸秆工艺研究

以磷钨酸为催化剂,混合多元醇为液化剂,在高压反应釜中对玉米秸秆进行催化液化试验。通过单因素和正交试验设计,详细考察催化剂用量、液化剂与玉米秸秆质量比(液固比)、反应时间和反应温度对玉米秸秆液化效果的影响。试验结果表明,在聚乙二醇400和乙二醇质量比6∶1,液固比12∶1,催化剂用量3%,反应时间75 min,反应温度150℃的条件下进行液化,玉米秸秆液化率为86.84%。     

微藻超临界甲醇直接酯交换法制备生物柴油

以规模化养殖的小球藻为原料,采用超临界甲醇酯交换法开展了制备生物柴油的实验研究。通过对原料藻粉的主要组成和实验产物的元素、化合物组成及基本理化特性进行分析,考察了不同工艺条件对产率的影响。结果表明,在甲醇与湿藻（50%含水量）配比为8∶1（mL∶g）、反应温度260℃、反应压力8 MPa和停留时间10 min的条件下,微藻生物柴油产率高达9%以上,具有与石化柴油接近的理化性质和成分组成。     

Characterization of products from fast and isothermal hydrothermal liquefaction of microalgae

We investigated nonisothermal (fast) and nominally isothermal hydrothermal liquefaction (HTL) of Nannochloropsis sp. microalgae for the production of biocrude. Biocrude yields ranged from 36 to 45 wt % (dry weight), with fast HTL with low mass loading giving the highest yield. This condition also gave the biocrude with the lowest heating value, which indicates there are compromises to be made between biocrude quantity and quality. The aqueous phase and biocrude product fractions were characterized using elemental analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS). This detailed level of analysis identified more than 30,000 unique molecular products. The aqueous phase products included compounds with the same molecular formulae as known herbicides, which may inform efforts in genetic engineering of algae and/or bacteria for cultivation on the aqueous phase. This detailed molecular‐level characterization provides some clues regarding the types of reactions that may take place during HTL. © 2016 American Institute of Chemical Engineers AIChE J, 62: 815–828, 2016     

Nitrogen distribution in the products from the hydrothermal liquefaction of Chlorella sp. and Spirulina sp.

The high contents of nitrogen-containing organic compounds in biocrude obtained from hydrothermal liquefaction of microalgae are one of the most concerned issues on the applications and environment. In the project, Chlorella sp. and Spirulina sp. were selected as raw materials to investigate the influence of different reaction conditions (i.e., reaction temperature, residence time, solid loading rate) on the distribution of nitrogen in the oil phase and aqueous phase. Three main forms of nitrogen-containing organic compounds including nitrogen-heterocyclic compounds, amide, and amine were detected in biocrudes. The contents of nitrogen-heterocyclic compounds decreased with temperature while amide kept increasing. The effect of residence time on the components of nitrogen-containing organic compounds was similar with that of temperature. However, the influence of solid loading rate was insignificant. Moreover, it was also found that the differences of amino acids in the protein components in the two microalgae might affect the nitrogen distribution in products. For example, nitrogen in basic amino acids of Spirulina sp. preferred to go into the aqueous phase comparing with the nitrogen in neutral amino acids of Chlorella sp. In summary, a brief reaction map was proposed to describe the nitrogen pathway during microalgae hydrothermal liquefaction.     

Coupling hydrothermal liquefaction and aqueous phase reforming for integrated production of biocrude and renewable H2

Lignin-rich stream from lignocellulosic ethanol production was converted into biocrude by continuous hydrothermal liquefaction (HTL) while hydrogen was produced by aqueous phase reforming (APR) of the HTL aqueous by-product. The effects of Na₂CO₃ and NaOH were investigated both in terms of processability of the feedstock as well as yield and composition of the obtained products. A maximum biocrude yield of 27 wt% was reached in the NaOH-catalyzed runs. A relevant amount of dissolved phenolics were detected in the co-produced aqueous phase (AP), and removed by liquid–liquid extraction using butyl acetate or diethyl ether, preserving the APR catalyst stability and reaching an hydrogen yield up to 146 mmol H₂ L⁻¹ AP. Preliminary mass balances integrating HTL and APR showed that the hydrogen provided by APR may account for up to 46% of the hydrogen amount theoretically required for upgrading the HTL biocrude, thus significantly improving the process performance and sustainability.     

松香裂解油的化学组成与性能分析

以活性白土为催化剂对松香进行催化裂解正交试验,并对裂解产物的化学组成及理化性能指标进行分析测试。结果表明:活性白土可以在较低的反应温度和较短的反应时间内对松香起到催化裂解作用,最佳工艺条件为:反应温度240℃,反应时间1.5 h,催化剂用量为松香质量的10%。裂解油酸值稳定在0.69～0.75 mg/g,得率稳定在60%～63%。气相色谱-质谱(GC-MS)分析表明,得到的非挥发性裂解油主要由苯、萘、酮、酯和菲等化合物组成,松香裂解油酸度为0.075 g/L,运动黏度(20℃)为47.6 mm²/s,冷凝点为-30℃,冷滤点为11℃,十六烷值为30.4。松香裂解油经过复配和性能改良,可达到石化柴油国家标准。     

神华上湾煤恒温阶段直接液化反应动力学

为考察神华上湾煤的直接液化性能及反应动力学,以加氢蒽油-洗油混合油作为溶剂、负载型FeOOH作为催化剂,在0.01 t·d^-1煤直接液化连续实验装置上考察了不同反应温度（435~465℃）、不同停留时间（7~110 min）下液化产品组成的演变规律。研究发现,随着煤的裂解及加氢反应的进行,煤及沥青类物质（PAA）收率不断减小,重质液化产物逐步向轻质液化产物转化。当反应温度为455℃、停留时间为90 min时,煤转化率为90.41%（质量分数（,油收率为61.28%（质量分数（。随着反应条件进一步苛刻,油收率下降。基于上湾煤直接液化反应特性及其产物收率变化规律建立了11集总煤直接液化反应动力学候选模型,以BFGS优化算法对实验数据搜索、选优,确定了动力学模型参数。检验结果表明所建立的动力学模型可用于恒温阶段直接液化行为的模拟计算。     

Liquefaction of cellulosic wastes: III. Production,characterization and evaluation of pyrolytic oils

Liquefaction of municipal solid wastes has been achieved in an atmosphere of hydrogen gas and in the presence of boric acid which catalyzes the pyrolysis reaction. Two petroleum distillates, namely gas oil and residual fuel oil, were used as carrier media of solid refuse. The yield of pyrolytic oil was studied as a function of different operational conditions (temperature, pressure of hydrogen, carrier oil medium and concentration of boric acid). Hydrocarbon constituents of the oil mixtures, produced by liquefaction of cellulosic wastes slurried in fuel oil, were investigated by means of gas chromatography. It was found that the oil mixture, obtained at optimum reaction conditions, showed pronounced occurrence of low hydrocarbons in the range C₃-C₁₅ as compared with the original fuel oil and the oil resulting from the pyrolysis of carrier oil without solid refuse. The residual pyrolytic char exhibited catalytic activity towards hydrocracking. It was suggested that the activity of char is due to the presence of transition metals as evidenced by an electron dispersion system (EDS). The hydrocracking activity of char seemed to be dependent on the operational conditions of the liquefaction. Multiple analytical parameters including API gravity, calorific value, total acid number and wt% of residue over 450°C were used to evaluate the oil mixtures produced as a petroleum crude oil. Carrier oils, particularly fuel oil, seemed to be highly modified in the course of the pyrolysis process. Also, the oil mixtures produced were distinguished from the original carrier oils by a considerably higher acidity due to association with oxygenated compounds which could be derived from cellulose macromolecules.     

高黏度生物原油的乳化及燃烧性能研究

利用畜禽废弃物水热液化制备的生物原油的残余物,因黏度大、流动性差、易聚合等特点,难以再利用。针对这一问题,设计研制了不同定-转子结构参数的齿合型高剪切混合器,研究了不同转子直径、剪切间隙、齿数和齿长等结构参数对所制备的乳化样品中液滴大小的影响;进而,采用优选的高剪切混合器,考察了乳化操作时间、转子转速、生物原油含量等因素对乳化效果的影响,并测定了乳化样品的燃烧性能。结果表明,随着转子转速的增加或操作时间的延长,生物原油乳化样品中液滴尺寸显著降低;在转子转速为7 700 r·min^-1,高剪切混合乳化操作时间30 min时,生物原油质量分数10%的乳化样品中液滴直径低于10 μm;乳化样品的燃烧性能显著提升,生物原油质量分数15%的高剪切混合乳化样品的燃烧效率达到95.3%,但是生物原油含量继续增大会使燃烧效率下降。     

水热处理对不同变质程度煤加氢液化反应性的影响

分析了4个温度下水热处理对不同变质程度煤加氢液化反应性的影响。结果表明:(1)200℃²50℃为褐煤和长焰煤加氢液化较好的水热处理温度。(2)在实验条件下,水热处理温度200℃250℃为褐煤和长焰煤加氢液化较好的水热处理温度。(2)在实验条件下,水热处理温度200℃²50℃,褐煤总转化率和油、气产率可达到84.70%和79.29%,沥青烯和前沥青烯产率为5.41%;长焰煤相对应的数据分别为78.2%、70.72%和7.48%。(3)水热处理温度>250℃或<200℃,褐煤和长焰煤液化反应性均降低。     

微拟球藻油脂萃取及脱脂藻水热液化

为提高微藻的综合利用效率,使用不同的溶剂系统分别对干、湿微拟球藻进行油脂萃取,并对脱脂后的藻渣进行水热液化实验,探究溶剂萃取脱脂对微藻水热液化产物的影响。溶剂萃取的结果表明,极性溶剂对油脂的萃取率达到25.0%,但对脂质的萃取缺乏选择,萃取物的脂肪酸甲酯产率仅为29.68%;混合溶剂萃取的脂肪酸甲酯回收率达到57.70%。脱脂后的微拟球藻水热粗油产率为27.7%~34.6%,氮含量为5.29%~6.68%,主要由脂肪酸、脂肪酸酯、脂肪酸酰胺、长链烃类、胺类、含氧化合物和含氮杂环化合物组成。经甲醇萃取后的湿藻水热粗油产率为34.6%,氮含量为5.44%,过程能耗低,表明甲醇萃取湿藻结合水热液化具有一定的应用前景。