Co-pyrolysis of petroleum based waste HDPE,poly-lactic-acid biopolymer and organic waste

Waste pyrolysis is widely investigated, but less information is available about their co-pyrolysis. The present paper discloses the waste pyrolysis and co-pyrolysis in batch reactor at 400 °C, 450 °C and 500 °C. The effect of the raw materials and temperature to the product was investigated. Product yield was increased and the quality (composition, contaminants, etc.) improved by co-pyrolysis. Gas and pyrolysis oil yields increased as function of temperature. Higher ratio of organic waste/petroleum based plastic waste resulted in lower yields of volatile hydrocarbons. Concentrations of oxygen containing products and contaminants are significantly changed with temperature or adding of HDPE into raw materials.     

神木烟煤与桦甸油页岩的共热解特性

采用热重分析仪和固定床反应器研究了神木烟煤和桦甸油页岩的混合共热解特性及协同作用机制. 结果表明,神木煤与桦甸油页岩混合共热解的失重率高于计算值,表明二者在热解和挥发分逸出过程中存在相互作用,促进了挥发分释放,减少了半焦生成. 煤与油页岩的协同作用可增加热解油收率、降低半焦和水收率. 油页岩与煤质量比为1:1时,所得油收率最高,为9.84%,比计算值提高8.8%. 共热解有助于提高轻质油含量和收率,油页岩与煤质量比为1:4时,轻质油含量超过80%,收率约为7.5%,比计算值分别提高了8%和11.2%,表明添加少量油页岩可明显提高热解油品质. 共热解过程中油页岩产生的富氢组分及自由基能抑制煤热解产生的芳香族化合物的聚合反应,促进芳烃向产物油转化,提高热解油的收率和品质.     

有机固体废弃物与煤共热解基础研究

利用分析热天平等仪器,通过TG技术对榆林长焰煤、济源焦煤、焦作无烟煤等3种不同煤化程度的煤及固体废弃物(塑料)在不同热解速度、不同混合比例下的热解实验研究。结果表明,煤与塑料共热解的影响因素很多,包括升温速度、煤化程度、混合比例、热解终温等。     

Co-pyrolysis of pine cone with synthetic polymers

Biomass from pine cone (Pinus pinea L.) was co-pyrolyzed with synthetic polymers (PE, PP and PS) in order to investigate the effect of biomass and plastic nature on the product yields and quality of pyrolysis oils and chars. The pyrolysis temperature was of 500 °C and it was selected based on results from thermogravimetric analysis of the studied samples. Co-pyrolysis products namely gases, aqueous and tar fraction coming from biomass, oils from synthetic polymers and residual char were collected and analyzed. Due to the synergistic effect in the pyrolysis of the biomass/polymer mixtures, higher amounts of liquid products were obtained compared to theoretical ones. To investigate the effect of biomass content on the co-pyrolysis, the co-pyrolysis of pure cellulose as model natural polymer for biomass with polymer mixture was also carried out. In the presence of cellulose, degradation reaction leading to more gas formation and less char yield was more advanced than in the case of co-pyrolysis with pine cone. Co-pyrolysis gave polar oxygenated compounds distributed between tar and aqueous phase and hydrocarbon oils with composition depending on the type of synthetic polyolefin. Co-pyrolysis chars had higher calorific values compared to pyrolysis of biomass alone.     

石脑油和轻烃资源裂解方式优选研究

由于我国轻烃资源缺乏,而石脑油资源相对丰富,考虑将其掺入石脑油进行共裂解。在实验室裂解装置上对油田轻烃、拔头油的分组裂解以及与石脑油共裂解的产物收率变化进行了研究,得出油田轻烃、拔头油的分组裂解优于与石脑油共裂解,因此探讨了拔头油与油田轻烃共裂解的可行性,提出在原料短缺的情况下,可根据"性质相近"的原则进行共裂解,即可将油田轻烃与拔头油掺混进行共裂解。同时在工业裂解炉上进行了拔头油与石脑油共裂解标定试验,得出的结论与实验室结论一致。     

固定床烟煤与木屑共热解的协同反应性研究

在自制的固定床反应装置上对木屑和烟煤以及两者的混合物进行了热解特性研究,考察了木屑与烟煤在不同掺混比例和热解终温下的共热解反应特性。研究结果表明:协同作用发生的程度与热解反应条件有关,烟煤与木屑共热解的协同反应性不仅体现在气、液产物收率方面,同时对气体组成也有显著影响;因木屑灰分中的碱金属化合物对热解焦油的催化裂解作用,使得共热解反应在较高热解终温和较低木屑掺混比条件下表现出更为显著的协同作用;在木屑掺混比(木屑质量分数)为25%、终温540℃条件下,热解气产率的协同值达到22.6%,焦油产率协同值为-27.3%;H自由基与烟煤热解产生的自由基结合成CH4等烃类气体或转移到焦油组分,是一种重要的协同作用机理。     

Theoretical study on the mechanism of sulfur migration to gas in the pyrolysis of benzothiophene

The release and control of sulfur species in the pyrolysis of fossil fuels and solid wastes have attracted attention worldwide. Particularly, thiophene derivatives are important intermediates for the sulfur gas release from organic sulfur, but the underlying migration mechanisms remain unclear. Herein, the mechanism of sulfur migration during the release of sulfur-containing radicals in benzothiophene pyrolysis was explored through quantum chemistry modeling. The C₁-to-C₂ H-transfer has the lowest energy barrier of 269.9 kJ·mol^–1 and the highest rate constant at low temperatures, while the elevated temperature is beneficial for C−S bond homolysis. 2-Ethynylbenzenethiol is the key intermediate for the formation of S and SH radicals with the overall energy barriers of 408.0 and 498.7 kJ·mol^–1 in favorable pathways. The generation of CS radicals is relatively difficult because of the high energy barrier (551.8 kJ·mol^–1). However, it can be significantly promoted by high temperatures, where the rate constant exceeds that for S radical generation above 930 °C. Consequently, the strong competitiveness of S and SH radicals results in abundant H₂S during benzothiophene pyrolysis, and the high temperature is more beneficial for CS₂ generation from CS radicals. This study lays a foundation for elucidating sulfur migration mechanisms and furthering the development of pyrolysis techniques.     

煤与油页岩热预处理特性及对热解的影响

对比研究了神木煤和桦甸油页岩在150~400℃热预处理时的孔隙变化和挥发分析出规律以及热预处理对后续慢速升温热解反应产物的影响。结果表明,热预处理显著增加了油页岩的孔隙结构,其比表面积提高4倍、孔体积提高5倍以上,而神木煤的孔隙结构则减少了,特别是孔径大于1 nm的孔体积减少了近60%、比表面积减少了近80%,而其1 nm以下的孔则相对稳定,孔体积和比表面积分别只减少了10%左右。低于400℃时热预处理过程中除脱去吸附水外,其他挥发分也有一定析出,并以CO₂为主,另有少量CO,但挥发分总失重量不超过5%。固定床慢速升温热解研究表明,经热预处理后,油页岩的油产率最高提高了22.7%,而水和气的产率则相应降低,气体中CH₄增加而H₂降低。热预处理对煤的热解油产率影响不明显,但热解水产率降低而热解气产率增加且其中CH₄增多而H₂降少。     

The isothermal degradation of wood

The results of a study of spruce (whitewood) and its organic components (cellulose, hemicellulose, and lignin) by isothermal thermogravimetric analysis in air and inert atmospheres are presented. Data on the thermal decomposition of fuel wood in a temperature range from 200 to 450°C were acquired. The porous structure of biocoal and the process of its evolution were examined by scanning electron microscopy. The porous structure of the whitewood thermally treated at 200 and 300°C had pore sizes from 4 to 15 μm. The stratification of tracheids occurred in the above temperature range. At higher temperatures of 350°C or above, thermal pores with sizes of about 100 nm appeared. As the temperature was increased to 400°C, the pore size increased to 200–300 nm.     

煤与稻壳共热解热重分析及动力学

利用热重分析仪对长焰煤和稻壳分别单独及按不同掺混比例进行热质量损失实验研究。通过比较煤与稻壳共热解热质量损失曲线和计算得到的理论曲线发现,添加稻壳对共热解过程有促进作用,在不同的稻壳掺混比例下,共热解过程质量损失率和最大质量损失速率均较理论值有不同程度的增大,推测稻壳掺混对共热解存在促进作用,促进作用与稻壳掺混比例不成线性关系。对煤与稻壳及共热解过程进行动力学分析,获得了反应活化能和频率因子,分析计算热解动力学参数表明共热解过程存在动力学补偿效应。     

Formation of 1-D ZnTe nanocrystals by aerosol-assisted spray pyrolysis

One-dimensional (1-D) ZnTe nanowires were prepared by aerosol-assisted spray pyrolysis using a mixture of ZnO (1 mmol)/OA (4 mL)/TOPO (0.8 g)/ODE (4 mL) as Zn precursor and Te/TOP (3 mL of 0.75M) as Te precursor. The shape, size, and crystal structure of products were characterized by means of transmission electron microscope (TEM) and X-ray diffraction (XRD). The shape evolution of ZnTe nanocrystals from nanodots to nanowires was achieved by controlling the reaction temperature. ZnTe nanodots with average diameter of 8.3 nm were synthesized at 300 °C. “Earthworm-like” shaped ZnTe (linear ZnTe aggregates) consisting of primary ZnTe nanodots of about 16 nm in diameter were obtained at 400 °C. In addition, 1-D ZnTe nanowires were prepared at reaction temperature higher than 450 °C. Those experimental results suggest that ZnTe nanowires with zinc blende structure are formed from ZnTe nanodots by the oriented attachment due to insufficient surface capping of surfactant molecules and by strong dipole-dipole interaction of nanodots, followed by self-organization of linear aggregates at higher reaction temperatures. The linear ZnTe aggregates consisting of primary ZnTe nanodots may be an intermediate stage in the formation process of nanowires from nanodots.     

A review on co-pyrolysis of coal and oil shale to produce coke

It has become the top priority for coking industry to rationally use and enlarge coking coal resources because of the shortage of the resources. This review focuses on the potential utilization of oil shale (OS) as a feedstock for coal-blending coking, in which the initial and basic step is pyrolysis. However, OS has a high ash content. If such OS is directly used for coal-blending coking, the coke product will not meet market demand. Therefore, this review firstly summarizes separation and beneficiation techniques for organic matter in OS, and provides an overview on coal and OS pyrolysis through several viewpoints (e.g., pyrolysis process, phenomena, and products). Then the exploratory studies on co-pyrolysis of coal with OS, including co-pyrolysis phenomena and process mechanism, are discussed. Finally, co-pyrolysis of different ranks of coals with OS in terms of coal-blending coking, where further research deserves to be performed, is suggested.     

Preparation and characterization of novel carbon molecular sieve membrane/PSSF composite by pyrolysis method for toluene adsorption

Carbon molecular sieve membrane (CMSM)/paper-like stainless steel fibers (PSSF) has been manufactured by pyrolyzing poly (furfuryl alcohol) (PFA) coated on the metal fibers. PFA was synthesized using oxalic acid dihydrate as a catalyst and coated on microfibers by dip coating method. For the purpose of investigating the effects of final carbonization temperature, the composites were carbonized between 400°C and 800°C under flowing nitrogen. The morphology and microstructure were examined by X-ray diffraction, Fourier transforms infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, N₂ adsorption and desorption, Raman spectra and X-ray photoelectron spectra. The consequences of characterization showed that the CMSM containing mesopores of 3.9 nm were manufactured. The specific surface area of the CMSM/PSSF fabricated in different pyrolysis temperature varies from 26.5 to 169.1 m²∙g⁻¹ and pore volume varies from 0.06 to 0.23 cm³∙g⁻¹. When pyrolysis temperature exceeds 600°C, the specific surface, pore diameter and pore volume decreased as carbonization temperature increased. Besides, the degree of graphitization in carbon matrix increased with rising pyrolysis temperature. Toluene adsorption experiments on different structured fixed bed that was padded by CMSM/PSSF and granular activated carbon (GAC) were conducted. For the sake of comparison, adsorption test was also performed on fixed bed packed with GAC. The experimental results indicated that the rate constant k′ was dramatically increased as the proportion of CMCM/PSSF composites increased on the basis of Yoon-Nelson model, which suggested that structured fixed bed padded with CMSM/PSSF composite offered higher adsorption rate and mass transfer efficiency.     

Co-pyrolysis of bituminous coal and biomass in a pressured fluidized bed

An experimental study on co-pyrolysis of bituminous coal and biomass was performed in a pressured fluidized bed reactor. The blend ratio of biomass in the mixture was varied between 0 and 100 wt%, and the temperature was over a range of 550–650 °C under 1.0 MPa pressure with different atmospheres. On the basis of the individual pyrolysis behavior of bituminous coal and biomass, the influences of the biomass blending ratio, temperature, pressure and atmosphere on the product distribution were investigated. The results indicated that there existed a synergetic effect in the co-pyrolysis of bituminous coal and biomass in this pressured fluidized bed reactor, especially when the condition of bituminous coal and biomass blend ratio of 70:30(w/w), 600 °C, and 0.3 MPa was applied. The addition of biomass influenced the tar and char yields and gas and tar composition during co-pyrolysis. The tar yields were higher than the calculated values from individual pyrolysis of each fuel, and consequently the char yields were lower.The experimental results showed that the composition of the gaseous products was not in accordance with those of their individual fuel. The improvement of composition in tar also indicated synergistic effect in the co-pyrolysis.     

Process analysis of catalytic multi-stage hydropyrolysis of lignite

The process and the mechanism of multi-stage hydropyrolysis (MHyPy) of coal were investigated by analyzing the products of different MHyPy processes in detail. The results showed that the suitable holding temperature was near the peak temperature (350–500 °C) at which more free radicals were produced rapidly, thus more oil was formed and the hydrogen utilization efficiency was increased. The cleavage of organic functional groups in char from MHyPy was mostly affected by the pyrolysis temperature. The effect of retention was to change the product distribution through stabilization of the free radicals and hydrogenation of the heavier products. In the holding stage the specific surface area and average pore volume of the char were increased due to the escape of more hydrogenation products.     

生物质和煤共热解特性及催化剂对热解的影响

为研究生物质和煤程序升温共热解特性及相互作用,利用热天平和管式炉反应器对白松木屑和五彩湾烟煤的共热解特性及催化剂对生物质和煤共热解的影响进行了研究,并考察了共热解半焦的孔结构特性。结果表明：不同比例的生物质和煤在共热解过程中,两者基本保持了各自的热解特性,由于生物质和煤的主要热解阶段温度相差较大,共热解过程中没有发生明显的协同作用。生物质和煤共热解半焦产率实验值大于计算值,当生物质质量分数从75%减少至25%时,半焦产率实验值与计算值之间的差值从0.81个百分点增加到1.07个百分点。橄榄石和载镍橄榄石（NiO/olivine）的添加促进了共热解反应发生的深度。载镍橄榄石催化剂添加（原料和催化剂质量比1：1）的条件下,共热解碳转化率提高了0.5%~5.1%,随着混合物中生物质比例的增加,催化剂的催化效果更加明显。     

Effect of pyrolysis temperature on cobalt phthalocyanine supported on carbon nanotubes for oxygen reduction reaction

Cobalt phthalocyanine (CoPc)-impregnated functionalized multi-walled carbon nanotubes (CNTs) were used as nonprecious electrocatalysts for oxygen reduction reaction (ORR). The electrocatalysts were thermally treated at temperatures ranging from 450 to 850 °C, and the effect of pyrolysis temperature and their relationship to the electrocatalytic activity for ORR were investigated. Thermo gravimetric analysis, X-ray diffraction, and electron microscopy were used to study the thermal stability, crystal structure, and morphology of these catalysts. Cyclic voltammetry and rotating disk electrode results showed that CoPc/CNTs pyrolyzed at a temperature of 550 °C had the highest electrocatalytic activity for ORR, and the catalytic activity decreased with further increase in pyrolysis temperature. X-ray photoelectron spectroscopy showed decrease in functional groups at a temperature higher than 550 °C, correlating with the decreased catalytic activity. The result suggests that oxygen functional groups introduced by acid oxidation for anchoring the CoPc on CNT plays a major role in determining the electrocatalytic activity.     

生物质与聚合物、煤共热解研究进展

综述了近几年来生物质与其它物质如煤和聚合物共热解的研究进展。通过对生物质、煤和聚合物的单独热解以及同煤和其它聚合物共热解的大量文献报道结果进行比较发现:生物质与许多聚合物共热解具有协同作用,可以降低液体产物的含氧量,提高热解液相产率等。显示出生物质与某些聚合物共热解比单独热解具有一定的优势;并比较了煤和生物质共热解产生的现象,得到煤和生物质共热解难以产生协同作用。本文作者结合现阶段的研究成果,提出生物质与煤采用两步法热解工艺的思路,使生物质材料的氢有可能转移到热解煤的产物中,以改善煤热解过程中液体的性质,对今后生物质与煤及聚合物共热解的研究方向提出了自己的建议。     

Influence of Substrate Temperature on the Properties of Cobalt Oxide Thin Films Prepared by Nebulizer Spray Pyrolysis (NSP) Technique

Cobalt oxide thin films are prepared by the nebulizer spray pyrolysis technique using cobalt chloride as the precursor material. The structural, optical, morphological and electrical properties are investigated as a function of substrate temperature (300–450 °C). The X-ray diffraction (XRD) analysis reveals that all the films are polycrystalline in nature, having cubic structure with preferential orientation along the (111) plane. The optical spectra show that the films are transparent (68 %) in the IR region. The optical band gap values are calculated for different substrate temperature. Photoluminescence (PL) spectra of the films indicate the presence of indigo, blue and green emission peaks with an ultraviolet emission peak centered around 368nm. SEM images reveals small sphere-like structures for the prepared Co3O4 films. The maximum conductivity obtained is 1.48 x 10?3 S/cm at 350 °C. The activation energy varies between 0.039 and 0.138 eV for the substrate temperature variation from 300-450 Q°C.     

Observation of transient free radicals during coal pyrolysis

Electron spin resonance studies of the early stages of carbonization of a high-volatile A bituminous coal have been used to detect and quantify transient free radicals present in the coal pyrolysate. Free radical (spin) populations are converted from susceptibilities measured at elevated temperatures assuming that the population present after ≈1 h of pyrolysis does not change when the coal pyrolysate is cooled to 20 °C. Co-carbonization of 9–10 dihydroanthracene and anthracene with the coal suggest that disproportionation pathways may be preferred over combination pathways as temperatures of pyrolysis and of liquefaction processes are increased.