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1.
生物质快速热裂解制取生物油试验研究   总被引:4,自引:0,他引:4  
本文在快速热解试验装置中对片状的白松样品进行制取生物油的试验研究.考察了运行参数对热解产物分布的影响,重点研究了各个参数对热解气体和生物油组分的影响规律.结果表明,气体产物中主要以CO、CO2、H2和CH4为主,CO、H2和CH4的浓度随着温度升高而上升.生物油主要含有有机酸类、苯酚类和糖类等化合物.在同一载气流量下,随着辐射源温度的增加,大分子产物的产量逐渐减少,小分子产物的产量有所增加.在同一辐射源温度下,随着载气流量的减小,小分子产物的产量呈增加趋势.  相似文献   

2.
流化床生物质快速热解制取生物油试验研究   总被引:4,自引:0,他引:4  
本文在小型流化床试验装置中对颗粒状的樟子松进行制取生物油的试验研究.考察了反应温度对热解生物油物理性质和产率的影响,并重点研究了各个参数对热解生物油组分的影响规律.结果表明,在550℃下生物油产率最高,为50.4%(w/w).随着热裂解温度升高,生物油的密度略有增加,生物油的粘度随着含水率的增加而减小.反应温度对生物油的主要化学成分和含量影响不明显,生物油主要含有有机酸类、酚类和糖类等化合物.  相似文献   

3.
金属盐对生物质热解特性影响试验研究   总被引:17,自引:1,他引:16  
基于深入了解生物质热解行为的目的,在自行研制的热解机理试验台上系统研究了金属盐对生物质热解的影响规律。试验结果表明,钾离子对生物油中的一些大分子量组分发生重聚反应生成焦炭和小分子气体产物具有强烈的催化作用,从而降低了热解生物油产量而得到更多的焦炭和气体产物。相比钾离子而言,钙离子对焦炭生成的促进作用更为强烈;镁离子对白松热解的影响远没有钾离子和钙离子明显。  相似文献   

4.
在污泥中添加醋酸钙或碳酸钙后进行热解,探究不同钙盐对污泥中低温热解过程含氮物质转化的影响。对150~550℃热解后气、液、固三态产物分析,确定了污泥中主要含氮物质为蛋白质,受热分解为胺类、杂环氮和腈类,然后继续分解产生大量NH3和HCN。污泥中添加钙盐,将抑制蛋白质分解,并促进腈类物质在固体产物中的生成和残留,减少焦油中含氮物质的产生。醋酸钙通过产生丙酮捕捉NH3,能减少近50%的NH3释放,而碳酸钙无明显影响。  相似文献   

5.
研究苯在30 Torr和1360~1820 K下的热解过程.利用同步辐射真空紫外光电离质谱技术对热解产物进行了检测,并对其随温度变化的摩尔分数曲线进行了测量.建立了一个低压苯热解动力学模型,并结合生成速率分析展示了燃料分解和芳烃生长过程中的主要反应网络.结果显示苯的分解主要通过氢提取反应生成苯基进行,部分通过单分子解离反应生成丙炔基或苯基进行,并终止于乙炔、丁二炔及1,3,5-己三炔等具有高热稳定性的聚炔烃类物种的生成.此外,低压苯热解中的芳烃生长过程起始于苯和苯基,并主要受到偶数碳增长机理控制.这是由于奇数碳增长机理所依赖的C5和C7物种在低压苯热解中很难生成.  相似文献   

6.
本文在流化床上对玉米芯进行了快速热解制取生物油的试验研究.首先在非催化条件下考察了温度、气体流量、床高和物料粒径对热解产物产率的影响,得到了制取生物油的最优工况.在此工况下进行了催化热解试验,研究了FCC催化剂对热解产物产率和生物油品质的影响.结果表明,最优工况下生物油产率为56.8%.同未加催化剂相比,FCC催化剂的存在使得生物油中油组分和焦炭的产率降低,不凝结气体、水分和焦的产率增加.分级冷凝系统的应用较好的实现了重油、轻油和水的分离.对催化条件下第二级冷凝器收集的生物油分析表明,其油组分的氧含量和高位热值分别为13.64%和36.7 MJ/kg,具有很好的应用前景.  相似文献   

7.
热解是废弃人造板高效回收利用的方式,人造板中所含胶黏剂是其不同于生物质的主要特征。为了有效环保地利用热解技术处理废弃人造板,解明人造板热解过程中其所含脲醛树脂胶黏剂(UF)对木材热解特性的影响,深入探索UF对人造板中木材各组分的作用机制,以杨木及木材的三种主要组分(纤维素、半纤维素、木素)为研究对象,创新性地依据杨木的化学组成,以纤维素、木聚糖和木素配制成模型物,并加入UF模拟人造板的构成。利用热重红外光谱联用(TG-FTIR)分析法,对比分析了加入UF前后模型物以及杨木各主要组分的热失重特性及气相演变规律。热重及红外结果表明,UF促进了纤维素热解过程中水和羧酸类物质的生成。UF与木素结合生成热不稳定的含氮结构,释放大量氨气,并且在200~300℃区间内参与了木素的热解并直接影响木素热解产物的生成。由此推测,在人造板热解过程中,木材三种主要组分中与UF作用的主要成分是木素。  相似文献   

8.
本研究通过几种纤维素的模型化合物(左旋葡聚糖、纤维二聚糖、纤维三聚糖、纤维四聚糖、葡萄糖、纤维二糖、纤维三糖)在Py-GC—MS上的快速热解实验,通过研究其热解产物的分布规律并比较几种主要产物的峰面积绝对值的变化,来揭示纤维素热解过程中糖类的生成机理及转化途径。实验结果表明,脱水糖和原糖在热解产物分布上存在很大的差异,原糖和脱水糖相比较,产物中糖类的峰面积百分比明显降低,伴随的是呋喃类的峰面积的明显增加;原糖中,5-羟甲基糠醛和糠醛产率均随着聚合度的升高而增加,脱水糖中则相反。两类糖的左旋葡聚糖的产率随着聚合度的升高增加,而左旋葡聚糖酮的产率随着聚合度的升高呈现相反的趋势。  相似文献   

9.
杜氏盐藻是一种单细胞真核藻类,属于绿藻(Chlorophyceae)团藻目(Volvocales),杜氏藻科(Dunaliellaceae),杜氏藻属(Dunaliella).近年来,盐藻作为一种新型生物反应器,用来生产药用蛋白或口服疫苗,具有独特的优点和广阔的应用前景.杜氏盐藻是一种微藻,具有光和作用效率高,生长周期短,产量大等特点,藻体不含细胞壁纤维结构,是利用热解制取生物油燃料的良好材料!  相似文献   

10.
羰基物是低温燃烧过程中产生的不完全氧化中间产物,主要产生在预混燃烧阶段。从化学反应动力学角度,分析了预混火焰条件下,燃油量、过量空气系数和调合比例等因素对生物柴油羰基物生成的影响。通过改变空气稀释比进行空气预处理,通过掺混氢气、掺混一氧化碳、掺混甲烷进行燃料预处理,对生物柴油羰基类污染物的排放控制进行了数值模拟。研究结...  相似文献   

11.
Pyrolysis of sewage sludge under conditions relevant to applied smouldering combustion was carried out in this study to investigate the influences of gas flow rate, oxidative atmosphere, and inert porous medium involvement on the properties of products. The experiments were carried out at 300–600 °C under atmospheres of N2, 5% O2/95% N2, 10% O2/90% N2, and 15% O2/85% N2, with Darcy flow rates of 1.0 and 3.5 cm/s, respectively, with dried sewage sludge loaded individually or as a mixture with sand. As a result, both the increment of gas flow rate and involvement of sand leaded to lower yields of char and higher yields of bio-oil and gas under N2 at temperature of ≤500 °C, due to the enhanced efficiency of pyrolysis reaction and gas transportation. However, when temperature increased to 600 °C, the influencing trends on product distributions changed due to the mechanisms of secondary cracking reaction and volatile-char interaction. The involvement of oxygen in fraction of ≤15 vol% at temperatures of 400–500 °C would lead to the intense decreasing yields of char and bio-oil, and increasing yield of the gaseous (dominated by CO2 and CO), due to the involved oxidation reaction during pyrolysis. Both increment of temperature and oxygen fraction would lead to the delay of ignition and the increase of activation energy of the produced char, except for that of char produced at 400 °C under 5% O2/95% N2, whose calculated activation energy was lower and volatile content was higher compared to that of char produced from pyrolysis at 400 °C under N2. The bio-oil from pyrolysis under N2 was dominated by aliphatic acids, phenols, steroids, amides, and indoles, etc., and the involvement of partial oxidation would lead to the weakened formation of aromatics, phenols, and S/Cl/F-containing compounds in bio-oil.  相似文献   

12.
Curie-point pyrolysis-gas chromatography coupled on-line to mass spectrometry (Py-GC/MS) and isotope ratio mass spectrometry (Py-GC/IRMS) were used to determine the individual turnover rate of specific carbohydrates, lignin, lipids and N-containing compounds from French arable soils. The analysed soils were cultivated, either continuously with a C3 plant (wheat delta(13)C-value = -25.2 per thousand), or transferred to a C4 plant (maize delta(13)C-value = -11.4 per thousand) cropping 23 years ago. Most pyrolysis products identified were related to carbohydrates (furans), lipids (hydrocarbons and derivatives of benzene), proteins (nitriles and pyrrole) and lignins (phenols). The relative yield of all individual pyrolysis products was similar in the samples from the maize and control wheat soil. The isotopic enrichment between identical pyrolysis products from the two soils varied from 1 to 12 delta (delta) units, indicating that after 23 years of cultivation 7 to 90% of their C was derived from maize. This suggests a slow mean turnover time varying from 9 to 220 years. Based on the differences in isotopic enrichment of chemical structures after vegetation change the pyrolysis products could be divided into three groups: (i) pyrolysis products with a nearly complete C4 signal, e. g. phenol, derived from lignin degradation products, (ii) pyrolysis products with an intermediate isotopic enrichment of 6-8 per thousand, most likely to be a composite of remaining (possibly physically protected) fragments derived from both maize and native wheat, and (iii) pyrolysis products showing only low enrichments in (13)C of 1-3 per thousand. Most of their precursors were found to be proteinaceaous materials. This indicates that proteins or peptides are indeed preserved during decomposition and humification processes occurring in the soil. Our study highlights the potential of Py-GC/MS-C-IRMS to further novel insights into the dynamics of soil organic constituents. Copyright 1999 John Wiley & Sons, Ltd.  相似文献   

13.
采用密度泛函理论理论方法M062X/6-311++G(d,p),对吡喃木糖的热解反应机理进行了理论计算分析。针对吡喃木糖热解可能发生的化学反应共设计了九条可能的热解路径,并对各路径中的反应物、中间体和过渡态的几何结构进行了能量梯度全优化,并在梯度全优化的基础上计算了各热解反应路径的热力学和动力学参数。文中以两大类方式来设计反应路径:1)木糖首先经过过渡态TS1发生开环反应生成链状中间体2,该步的反应能垒为188.7 kJ/mol,对于中间体2共设计了五种可能的热解反应路径;2)考虑双键同时断裂的情况,木糖先发生脱水反应,接着按C-C和C-O键同时断裂的情况发生开环反应,针于这种情况共设计了四条可能的热解路径。计算结果表明,吡喃木糖热解的主要反应产物有乙醇、乙醛、糠醛、丙酮、酸类、CO2和CO等小分子化合物。  相似文献   

14.
The fast pyrolysis of biomass with catalysts is a promising route for producing upgraded bio-oil as an alternative energy source. A CaO catalyst prepared from organic calcium compounds (Org-CaO) was first used to upgrade the pyrolysis oil of Jatropha curcas seeds in situ. Calcium d-gluconate monohydrate, calcium citrate tetrahydrate, and calcium acetate hydrate were employed as the organic precursors in this work. The results showed that Org-CaO exhibited better deoxygenation ability to produce more hydrocarbons than conventional CaO derived from Ca(OH)2 (CHCaO). Acids accounted for 83% of the oxygenated compounds in the raw bio-oil and were almost completely removed via CaO. For bio-oil catalyzed by Org-CaO, the fraction of esters in the oxygenated compounds was only ~9%, which was 20% less than that in CHCaO bio-oil. The relative content of ketones and alcohols in Org-CaO bio-oil increased by 16% versus that in CHCaO bio-oil. Org-CaO exhibited a remarkably larger pore size and much smaller particle sizes. Thus, Org-CaO entered into the fuel through the pore channels, and this promoted the formation of chemical crosslinking points between CaO and oxygenated groups. In addition, the basicity and the amount of basic sites for Org-CaO increased versus CHCaO. Thus, the adsorption forms of oxygen-containing groups in the bio-oil on the basic sites of CaO changed: the carboxyl groups were removed from the acids and were absorbed in a stable form of unidentate carbonate on oxygen vacancies (O2?). The stable form was bidentate carbonate on Ca2+–O2?. In addition, oxygen vacancies on Org-CaO extracted more hydroxyl groups from the acids, resulting in dehydroxylation of acids to form ketones and alcohols.  相似文献   

15.
Understanding the chemical reactions during biomass and alkaline additives during pyrolysis process is critical to better utilization of biomass resource. In this study, the influence of seven alkaline additives (KOH, K2CO3, KHCO3, CH3COOK, NaOH, Ca(OH)2, and Mg(OH)2) on biomass pyrolysis was investigated in fixed-bed system, as well as the reaction mechanism through combining the evolution properties of biochar, bio-oil, gas products, and alkaline additives. Results showed that alkaline additives promoted the formation of biochar and gas products, while inhibited the generation of bio-oil. The content of phenols (reaching 80% for NaOH, mainly non?methoxy phenols) and hydrocarbons (reaching 38% for Ca(OH)2, mainly aromatics) increased greatly at the cost of acetic acid and O-species. Carbon content of biochar decreased largely, while oxygen content increased greatly, and the main O-containing species were –OH, -O–CO and -COOH groups. The surface area of biochar also increased greatly (reaching 764 m2/g for KOH). During pyrolysis process, alkaline additives could react with high active O-containing species and carbon fragments to generate lots of vacancies, then some anions of alkaline additive quickly occupied these vacancies to form new O-containing groups in biochar. Alkaline additives also converted into more stable structure (K2CO3, Na2CO3, CaO, and MgO). The possible reaction pathway between biomass and alkaline additives was first proposed.  相似文献   

16.
生物质热裂解生物油特性的分析研究   总被引:33,自引:3,他引:30  
基于生物油广泛应用的目的,对生物油的理化特性进行了深入的研究。结合色质联机技术分析了由流化床热裂解水曲柳获得的生物油主要组分的分布。生物油由于高含氧量需要进一步改性才能高端应用。  相似文献   

17.
全梗全叶再造烟叶热裂解产物与感官质量关系研究   总被引:1,自引:0,他引:1  
通过对全梗、全叶单体原料制备的再造烟叶热裂解产物GC-MS鉴定分析,探讨热解产物的差异性对感官质量的影响。结果表明,梗、叶单体原料制备的再造烟叶热裂解产物主要包括醛、酮、酚、芳烃、杂环类物质,其中全梗再造烟叶检出49种物质,全叶再造烟叶检出60种物质。全叶再造烟叶热裂解产物中的主要烟草中重要的致香物质醛、酮、酚类物质的数量和所占比例明显高于梗再造烟叶;芳烃和杂环类物质的数量和所占比例较接近;全叶再造烟叶在香气质、杂气、刺激性方面明显优于全梗再造烟叶,这与全叶再造烟叶热裂解产物中的烟草主要致香成分释放量明显高于全梗再造烟叶有直接关系。  相似文献   

18.
Reaction of barbituric acids with aldehydes and dihydropyridines in one pot under microwave (MW) irradiation in the absence of solvent, affords 55–82% of the 5-benzylated barbituric acids. Use of alkyl nitriles or barbituric acids with indole-3-aldehyde and dihydropyridine (DHP) afforded 3-alkylated indoles in 57–76 % yield. In each case DHPs are converted to pyridines.  相似文献   

19.
Reaction of mineral acids with a cyclic macromolecule containing a secondary alcohol produces ammonium, phosphonium, thiophene, and amide adducts via a carbocation intermediate. X‐ray crystallography confirms the structures of the products, including those when two competing nucleophiles are present. A reactivity series that mirrors the nucleophilicity index, where reactivity decreases in the order thiophene > pyridine > primary amides > alkyl nitriles >> aromatic nitriles (unreactive), results. Addition of metal ions to ammonium adducts dissolved in acetonitrile produces secondary amides via the Ritter amide synthesis. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

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