煤热解特性研究

对大雁、协庄和昔阳3个不同煤化程度的煤样，在N2，CO2和水蒸气3种不同气氛及不同温度下进行了热解研究，考察了煤化程度、热解气氛和热解温度对煤热解产物产率和热解气性质的影响规律．研究表明，对上述3个煤样，随煤化程度加深，焦产率增加，油和气产率一般随煤中挥发分增加而增加，但又与煤的大分子结构、热解温度和加热速率等有密切关系；干馏气组成H2和CH4含量协庄煤样最高，而(CO CO2)含量因煤中氧含量的降低而下降．与N2气氛相比，CO2和水蒸气气氛中半焦产率下降，气产率增加；油产率水蒸气气氛下最高．H2组分含量在水蒸气气氛下最高，而CO，CH4和烃类C2～C5组分则最低．LHV在N2，CO2和水蒸气气氛下逐次降低．     

不同热解温度下禾本科植物生物炭理化特性分析

以禾本科植物王草、水稻秸秆、甘蔗渣和玉米秸秆为原料,在厌氧条件下于300、500和700℃制备王草炭(I)、水稻秸秆炭(R)、甘蔗渣炭(S)和玉米秸秆炭(M),研究了不同热解温度对生物炭结构及组成的影响.研究结果表明:随着热解温度升高,4种生物炭产率下降,300℃时I、R、S和M的产率分别为45.81％、48.67％、...     

热解温度和反应气氛对输送床煤快速热解的影响

在连续进料量为1.2 kg·h^-1的输送床反应器中考察了热解温度和反应气氛对不连沟次烟煤快速热解的影响。N₂气氛下,随着煤热解温度升高,焦油产率先增加后减小,600℃时达到最大值10.3%;对应的半焦产率下降,气体产率以及气油比增加。高温促进了煤挥发分的释放以及挥发分在气相中的二次反应,部分产物从固相和液相产品转化为气相产品,氢气、甲烷和乙烯等气体组分的产率明显增加。700℃下,H₂气氛能够抑制挥发分二次反应的发生,起到稳定自由基和加氢的作用,显著提高焦油产率和油品品质,同时有利于甲烷的生成。CO气氛在一定程度上同时提高了轻质和重质焦油产率。CO₂和水蒸气能够促进焦油的二次反应,特别是重质焦油的裂解,具有一定的提质作用,但会导致焦油产率下降。CH₄气氛促进了重质焦油组分的生成,使得热解焦油产率提高。     

氧含量对热解废轮胎产物影响研究

以含氧木屑为探针材料,同废轮胎以不同比例共热解以准确控制其氧含量,考察氧含量对热解废轮胎得到的气、液、固三相产物的影响及多环芳烃(PAHs)含量的影响。采用热重分析仪(TG)、元素分析仪(EA)以及气相色谱仪(GC)分别对它们热行为、热解油中氧含量及PAHs的变化规律进行了观察。TG分析表明,木屑中氧含量对废轮胎热解最大失重速率发生的温度产生了推后的影响。在木屑∶废轮胎质量为2∶1时,温度滞后3.7℃。EA分析表明,热解油中氧含量越高,氢含量较加权值越低,碳含量基本不变。GC分析表明,适量木屑所含的氧能够有效抑制PAHs的生成;对三相产物影响表明,氧含量越高,液体产率较加权值越小,气体产率较加权值越大,固体产率较加权值有所降低但与氧含量多少关联不明显。通过木屑和废轮胎共热解过程氧含量对热解产物影响的分析,为科学利用生物质、合理处置废轮胎提供科学帮助。     

N2/CO2气氛下木屑生物质热解特性的实验研究

本研究利用固定床管式炉开展了不同N2/CO₂比例气氛下的木屑生物质热解实验,考察了CO₂浓度、载气流速和停留时间对热解油和焦炭产率的影响。结果表明：热解油和焦炭的产率随反应温度和停留时间的增加而降低,热解油产率随反应气氛中CO₂浓度的升高而增加。在N₂和CO₂气氛下,载气流速升高均使热解油产率下降,而焦炭产率则在15%左右保持不变。添加HZSM-5和ZIF-67两种催化剂,发现ZIF-67在CO₂气氛下的热解油产率可以达到72.3%,相比其在N₂气氛下的热解油产率提升了近1.5倍;而HZSM-5由于其微孔孔道对生物质大分子传质的限制,产生最多焦炭(24.1%)。     

高结晶度石墨膜前驱体" Kapton"薄膜热解行为的研究

研究了制取高结晶度石墨膜用的聚酰亚胺薄膜“Kapton”在氮气气氛里加热到1000℃的热解行为。实验表明,样品大量质量损失和尺寸收缩发生在500～800℃区间,当温度超过800℃后,其趋于缓和。考察了样品的热解动力学,对相关活化参数的变化进行了一定讨论。用原子力显微镜(AFM)观测了热解1000℃时样品的表面形貌,认定其表面结构带有含氮的杂环缩合芳香层面的类石墨炭微晶,这些炭微晶的堆积呈现较为混乱和不规则状态。     

轮胎粒径对热解产物的影响

最终热解温度500℃,升温速率20℃/min的条件下,以管式炉热解实验和热重分析为基础,研究了轮胎粒径对废轮胎热解产物的影响。结果表明,在轮胎样品粒径从2 mm减少到0. 1 mm时,热解油产率增加了12. 9%;固体产物产率由52. 1%降低到了39. 4%;同时减小轮胎样品粒径有助于降低热解炭中结焦与积炭的含量;当轮胎粒径达到0. 2 mm后继续减小轮胎样品粒径对热解油产率几乎没有提高。     

平朔煤的热解试验研究

对平朔煤在不同温度下进行了热解研究,考察了热解温度对煤热解产物产率和热解气性质的影响规律。研究表明,对上述煤样,随煤的热解温度升高,半焦产率下降,干馏气产率增加;液体率在一定温度范围内先增后降,在600℃左右达到最高。热解温度升高,热解气中H2的含量就越高,热解气中CH4的含量在热解温度550～650℃左右达到最高。随热解温度的升高,CO2的含量显著降低,烃类组分随温度升高是先升后降,峰值出现在600℃左右。     

轮胎粒径对热解产物的影响

最终热解温度500℃,升温速率20℃/min的条件下,以管式炉热解实验和热重分析为基础,研究了轮胎粒径对废轮胎热解产物的影响。结果表明,在轮胎样品粒径从2 mm减少到0. 1 mm时,热解油产率增加了12. 9%;固体产物产率由52. 1%降低到了39. 4%;同时减小轮胎样品粒径有助于降低热解炭中结焦与积炭的含量;当轮胎粒径达到0. 2 mm后继续减小轮胎样品粒径对热解油产率几乎没有提高。     

不同种类生物质热解炭的特性实验研究

在管式炉上进行了生物质热解实验研究,分析了热解温度对生物质热解炭产量的影响规律,对比研究了农作物类和木材类生物质在相同热解条件下热解炭产量的差异,对生物质热解炭进行了电镜扫描分析,分析了不同热解温度下炭的表面结构特征。结果表明,生物质热解炭产量随热解温度升高而降低, 芸香木和稻壳的炭产量分别由300℃时的28.38%和45.84%降低到600℃时的7.55%和15.45%。在相同热解条件下,农作物热解炭产量普遍高于木材热解炭, 在400℃时稻壳糠热解得到的炭产量最高为30.32%,红胡桃热解得到的炭产量最低为19.23%。SEM分析表明,热解炭产物呈现多孔结构。     

Kinetics of reactions involved in pvrolvsis of cellulose II. The modified kilzer-bioid model

At temperatures below 300°C, it has been shown that the pyrolysis of cellulose can be modeled in terms of a modified Kilzer-Broido ((K-B) Model. According to this model, cellulose decomposes via two competitive reactions, a dehydration reaction to form anhydrocellulose and a depolymerization reaction to form levoglucosan. Anhydrocellulose later decomposes to chars and gaseous products via two competitive reactions. Arrhenius parameters and a technique of estimating empirical constants from experimental data for the K-B type reactions are presented. Comparison of the ability of the modified K-B model and the three reaction model to predict weight loss, product yields and heat pretreated results are also made.     

Kinetics of reactions involved in pyrolysis of cellulose I. The three reaction model

Kinetics of reactions involved in pyrolysis of cellulose has been modeled in terms of a three reaction model. In this model it is assumed that cellulose decomposes to tars, chars and gaseous products via three competitive first-order reactions. Arrhenius parameters have been obtained to describe the rate constants of these reactions. The three reaction model predicts the weight loss data reasonably well. Product yields of tars, chars and gases predicted by the three reaction model are compared over the temperature range 250 to 360°C. In this communication a technique for analyzing experimental data of a solid state reaction is presented.     

生物质热解反应装置研究现状及展望

生物质热解是实现生物质能源化利用的重要途径,对解决日益严重的能源问题有着重要意义。着重介绍了几种典型的生物质热解反应器的研究现状,并列举了近期开发出的几种新型热解反应装置,总结了不同种类的热解反应器的工作原理及各自优缺点和适用情况。对催化热解和生物质原料预处理及反应器进行了综述,指出开发新型高效、高活性热解催化剂和加大对原料预处理技术的基础理论探索力度是未来生物质热解研究的发展方向。     

Kinetics of the pyrolysis of utah tar sands

Utah tar sands have been pyrolyzed experimentally in a tubular furnace into a stream of nitrogen. Various condensate products have been collected and analyzed, and the pyrolyzed sands have been analyzed for coke and unreacted bitumen. The kinetics of the pyrolysis appeared to be second order under conditions of approximately constant temperature and in experiments with continuously changing temperatures. A lighter product with less sulfur, nitrogen, and arsenic was produced when more rapid heating rates were used. Other characteristics of the reaction and products are presented.     

Kinetic study of fast pyrolysis of sawdust in a conical spouted bed reactor in the range 400–500 °C

An original reactor (a conical spouted bed reactor) is used for the kinetic study of Pinus insignis sawdust pyrolysis in the range 400–500 °C under the usual conditions of this reactor for pyrolysis in a continuous regime. The equipment meets the requirements for pyrolysis kinetic study (bed isothermality, high mass and heat transfer between phases and short residence time of gaseous products). The results of yield of products are evidence of the good performance of the conical spouted bed reactor for obtaining a liquid product, with a maximum yield of 70 wt% in the range 440–460 °C. © 2001 Society of Chemical Industry     

Kinetic studies of the pyrolysis of sewage sludge by tga and comparison with fluidized beds

The pyrolysis of sewage sludge was examined by thermogravimetric analysis using different heating rates, particle sizes and final temperatures. A semi-empirical model was developed with four global consecutive/competitive reactions to volatile and solid products including also a heat balance. This model was extrapolated to isothermal reactor conditions and compared to experimental data on fluidized bed pyrolysis. Depending on the particle size and reactor temperature, about 90% of the maximum conversion in a fluidized bed takes place under external heat transfer control, the rest under kinetic control. Incomplete conversion occurs at short particle residence times, which were calculated approximately by the model.     

二次反应对煤热解产品组成的影响

煤的热妥是煤炭转化过程中的第一步，通过热解可以产生高质量的热解煤气及珍贵的液体产品。然而在实际过程中，对热解产品的组成有不同的要求。因此，研究煤热解二次反应对实际过程有着重要的指导意义。     

煤热解制焦油的工艺研究进展

煤热解是一种重要的煤炭分质利用技术,中低温热解焦油是制取液体燃料和化学品的重要原料。本文从对煤进行预处理、改变热解气氛、催化热解与催化加氢热解、煤与其它物质共热解、新型耦合热解工艺等方面综述了煤热解制焦油的工艺研究进展,探讨了影响煤热解过程焦油产率的因素及机理,并对各工艺进行了评价。     

Kinetic modelling of the pyrolysis of biomass and biomass components

The kinetics of the pyrolysis of lignocellulosic materials was studied with a view of providing simple kinetic models for engineering purposes. Experimental data obtained by means of thermal analysis techniques suggest that the pyrolysis of fine particles (below 1 mm) can be considered to be controlled by pyrolysis kinetics. The rate of pyrolysis of one biomass type can be represented by the sum of the corresponding rates of the main biomass components (cellulose, lignin, hemicellulose). The kinetics of each of these components was simulated by a kinetic scheme capable of predicting the pyrolysis rate and the final weight-loss for a wide range of pyrolysis parameters including various heating conditions.