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采用裂解气相色谱一质谱法研究了在350~750℃之间聚苯硫醚(PPS)的裂解行为。350℃时裂解,仅检测到4种裂解产物。随裂解温度上升,裂解产物急剧增加。在750℃时,检测到25种裂解产物,主要特征裂解产物为硫化氢、苯、苯硫醇、1,4-苯二硫醇、二苯硫、二苯并噻吩、1,4-苯二硫醇基苯、噻茚等。聚苯硫醚裂解过程中,发生链剪切作用,由聚合物链断裂成苯硫醇单体、二聚体和三聚体等化合物。裂解过程还会发生重排,环化,次级反应等形成了各种裂解产物。 相似文献
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C4/C5烃催化裂解制低碳烯烃的研究进展 总被引:1,自引:0,他引:1
从催化剂类型、裂解工艺、催化裂解的影响因素和裂解机理4个方面对国内外C4/C5烃催化裂解制低碳烯烃的研究进行了综述。催化裂解制低碳烯烃催化剂主要采用ZSM-5分子筛系列催化剂,在此基础上发展了酸改性或水热改性高硅ZSM系列分子筛及介孔MCM41分子筛。总结了国内外C4/C5烃的裂解工艺,认为影响催化裂解的主要因素是裂解原料、催化剂类型及工艺条件。目前,裂解机理主要是自由基与碳正离子机理相结合的机理。并简述了本课题组目前有关C4烷烃催化裂解的主要研究进展。 相似文献
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分析裂解技术在高分子研究中的进展 总被引:7,自引:0,他引:7
介绍了裂解同时衍生化和直接裂解-质谱等分析裂解技术,综述了近年来分析裂解技术在高分子表征、热分解机理、高分子加工等研究领域的主要进展。 相似文献
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水热裂解开采稠油技术研究的进展 总被引:20,自引:1,他引:20
从水热裂解反应、催化作用下的水热裂解反应、反应机理及水热裂解开采稠油现场应用实验等四个方面综述了国内外水热裂解开采稠油技术的研究进展。并对此技术的研究成果及未来发展进行了探讨,认为水热裂解开采稠油技术具有很高的潜在价值,是未来经济高效开采稠油的新途径。当前水热裂解开采稠油技术的主要研究方向是深入研究高温水的特性及其作用;对更多稠油中可能参与水热裂解反应的不同组分,选用合适的模型化合物进行模拟实验或其它方法,建立这些组分的反应热力学和动力学模型库;然后,根据具体稠油中所含的组分,设计水热裂解反应的路线,选择合适的催化剂,促使反应向稠油改质降粘的方向进行。其中,最关键的还是针对不同稠油研制成本低、活性和选择性高、反应条件宽的催化剂,并筛选或研制协同效果好的助剂,进而研究催化剂及其助剂在油层中与稠油作用的机理,设计合理的现场实施技术和工艺。 相似文献
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裂解气相色谱-质谱联用技术研究黑香豆酊的热裂解行为 总被引:1,自引:0,他引:1
采用裂解气相色谱-质谱联用法研究了香精黑香豆酊在不同温度下的裂解行为,分析了黑香豆酊在不同温度下的热裂解产物,并用归一化法进行了定量。结果发现黑香豆酊在不同温度下表现出不同的转移行为,其热解产物和机理也各不相同。检索到苯并呋喃、香豆素和肉桂醛等16种致香物质。随着温度的升高,裂解产物中逐渐产生出有害物质。初步探讨了香豆素可能的裂解机理,为香味物质在卷烟燃烧过程的转化行为提供了例证。 相似文献
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Kwang Chul OhChun Beom Lee Eui Ju Lee 《Journal of Analytical and Applied Pyrolysis》2011,92(2):456-462
This experiment involving diesel fuel pyrolysis was performed to study the process of soot formation without oxidation. The effects of temperature, residence time, and lubricating oil presence on soot formation were investigated through measurement of particle size distribution, morphology, and C/H ratio as well as through thermal analysis. The results show that the formation of soot during diesel pyrolysis depended strongly on both temperature and residence time. The critical temperature for the creation of soot with a primary particle diameter of 20 nm was about 1100 °C. Greater temperatures and residence times resulted in diesel soot particles that were more mature, i.e., with a higher C/H ratio, larger particle size, and higher ignition temperature. The carbonization of diesel soot through pyrolysis was also weakly affected by the addition of 5% lubricating oil to the diesel fuel. The results of this experiment provide information for modeling the formation of diesel soot without oxidation as well as for developing soot generators for after-treatment systems. 相似文献
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Janewit WannapeeraBundit Fungtammasan Nakorn Worasuwannarak 《Journal of Analytical and Applied Pyrolysis》2011,92(1):99-105
Torrefaction is the thermal treatment techniques performed at relatively low temperature (<300 °C) in an inert atmosphere, which aims to improve the fuel properties attractively. In this study, woody biomass (Leucaena leucocephala) was torrefied at various temperatures and holding times and the pyrolysis behaviors of the torrefied wood were examined in detail by using TG-MS technique. It was found that the carbon content and the calorific value of the torrefied leucaena increased significantly when temperature and holding time during the torrefaction increased. From the TG-MS analysis, the pyrolysis behaviors of the torrefied leucaena were significantly different from those of the raw leucaena. The char yield at 800 °C for the torrefied leucaena was increased when increasing the holding time during the torrefaction. On the other hand, the tar yield during the pyrolysis decreased significantly with the increase in the holding time during the torrefaction. Through the results from the TG-MS analysis, it was concluded that the structure of leucaena was changed by the torrefaction at temperature below 275 °C and the cross-linking reactions occurred during the pyrolysis resulting in increase in char yields and decrease in tar yields. It was also suggested that the longer the holding time during the torrefaction, the more the cross-linking reactions proceed during the pyrolysis. The results obtained from the study provide the basic information for the pyrolyser and/or gasifier design by using torrefied biomass as a fuel. 相似文献
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R. Xu L. Ferrante C. Briens F. Berruti 《Journal of Analytical and Applied Pyrolysis》2009,86(1):58-65
The pyrolysis of two grape residues (grape skins and the mixture of grape skins and seeds) has been carried out in a pilot bubbling fluidized bed pyrolyzer operating under a range of temperature from 300 to 600 °C and three vapor residence time (2.5, 5, and 20 s), with the aim of determining their pyrolysis behavior including products yields and heat requirements. The composition of the product gases was determined, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers and separated into two phases, an aqueous phase and an organic phase. The chemical composition of these liquid phases was characterized. In addition, the environmental parameters of the distilled fraction (85–115 °C) of the aqueous phase were tested, while the heating value of the organic phase was determined. Furthermore, the thermal sustainability of the pyrolysis process was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The optimum pyrolysis temperatures were identified in terms of maximizing the liquid yield, maximizing the energy from the product bio-oil, and maximizing the net energy from the product bio-oil after ensuring a self-sustainable process by utilizing the product gases and bio-oil as heat sources. 相似文献
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森林泥炭的热解特性及热解动力学 总被引:3,自引:0,他引:3
泥炭阴燃是森林地下火的主要燃烧形式之一, 研究泥炭的热解规律对认识其阴燃机理及地下火蔓延机理有重要意义. 本文使用荧光光谱分析技术测定了我国东北林区一种典型泥炭样品的主要元素组成, 并使用热重-差热分析(TG-DTA)技术研究了泥炭样品在惰性气氛中的热解规律. 实验结果表明, 泥炭样品主要由45种元素构成. 从常温到1073 K高温的升温过程中, 泥炭样品的质量损失过程可以分为三个阶段, 依次为水分损失阶段、有机质热解阶段和矿物质分解阶段. 对于泥炭阴燃密切相关的有机质热解阶段, 结合热分析动力学理论和优化计算方法, 建立了描述泥炭有机质热解动力学规律的三组分叠加反应模型. 相似文献
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A two-stage reaction process was used to convert polypropylene (PP) into multi-walled carbon nanotubes (MWCNTs) and hydrogen-rich gas. The proposed process consisted of two stages: catalytic pyrolysis of PP over HZSM-5 zeolite in a screw kiln reactor and the subsequent catalytic decomposition of pyrolysis gases over a nickel catalysts in a moving-bed reactor for producing MWCNTs and hydrogen. The resultant gas mainly consisted of hydrogen and methane. SEM and TEM images revealed that carbon products in the moving-bed reactor were in the form of MWCNTs. XRD and TGA characterization indicated that high decomposition temperature resulted in the formation of more highly crystalline nanotubes. The influence of pyrolysis temperature (550-750 °C) and decomposition temperature (500-800 °C) on the performances of the two-stage reaction system were investigated. The MWCNT yield and hydrogen concentration increased with an increase in the decomposition temperature and reached a maximum at 700 °C. With increasing pyrolysis temperature the yield of pyrolysis gas increased while the liquid yield decreased. The yield of MWCNTs in the moving-bed reactor was determined by both the quantity and quality of the pyrolysis gas. 相似文献
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A.I. Balabanovich D. Pospiech L. Hußler C. Harnisch M. Dring 《Journal of Analytical and Applied Pyrolysis》2009,86(1):99-107
The pyrolysis behavior of aromatic–aliphatic polyesters containing either a pendant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) group or a phosphine oxide group incorporated into the polymer backbone was studied using a combination of thermogravimetry and pyrolysis-GC/MS. The behavior of the phosphorus polyesters was compared to that of non-phosphorus-containing reference polymers. It could be shown that the DOPO group mainly does not interfere with the polyester decomposition. It produces two main pyrolysis products, o-hydroxybiphenyl and dibenzofuran, with the latter one requiring a higher pyrolysis temperature. Minor products containing the DOPO ring result from secondary decomposition reactions. In contrast, the phosphine oxide group strongly modifies the polyester pyrolysis behavior by decreasing the degradation temperature and changing the composition of pyrolysis products. Among of those, phosphinites and a phosphinate could be identified indicating rearrangement processes of the phosphine oxide group taking place upon pyrolysis. Mass spectra of organophosphorus products and pyrolysis schemes of polyesters are discussed. 相似文献
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Roberta Piccaglia 《Journal of separation science》1992,15(2):85-88
Grass forage samples with different fiber content and composition, and their fibrous fractions, have been analyzed by pyrolysis – gas chromatography with ion trap detection. The identities of the pyrolysis fragments indicated their origin to be carbohydrates, lignin, and nitrogen compounds. Comparison of the resulting quantitative data by factorial variance revealed pyrogram peaks attributable to neutral detergent fiber, cellular contents, and lignin. Quantitative pyrolysis data from these components showed the same trends as those recorded by the method of Goering and Van Soest [1]. 相似文献
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Properties of ethylene-propylene copolymer (EPM) are determined by ethylene/propylene ratio and degree of block and random sequences. EPM was pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to examine pyrolysis products formed from the ethylene-propylene heterosequences. Pyrolysis products formed from EPM were compared with those formed from polyethylene (PE) and polypropylene (PP) to determine the pyrolysis products formed from ethylene-propylene heterosequences of EPM. Principal pyrolysis products formed from ethylene-propylene heterosequences were 3-methyl-1-hexene, 4-methyl-1-hexene, 2-methyl-1-hexene, and 2-heptene. Order of the relative intensity of the pyrolysis products was 2-methyl-1-hexene > 4-methyl-1-hexene > 3-methyl-1-hexene > 2-heptene. The relative abundances of the pyrolysis products decreased as the pyrolysis temperature increased. Relative abundances of the specific pyrolysis products formed from ethylene-propylene heterosequences may be used for determination of the relative degree of random sequences of EPM as well as ethylene-propylene-diene terpolymer (EPDM). 相似文献
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The pyrolysis behaviors of l-tyrosine-based phthalonitrile(TPN) resin were investigated by thermogravimetric-Fourier transform infrared spectrometry-mass spectrometry (TG-FTIR-MS) and Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The small molecules produced during pyrolysis process of TPN resin were tracked in real time by TG-FTIR-MS. The larger molecules (m/z > 40) from fast pyrolysis at 900 °C of the TPN resin using Py-GC/MS were identified. From TG-FTIR-MS and Py-GC/MS results, the production pathways of pyrolysis products such as CO2, CO, NH3, benzonitrile and phenol were analyzed. The possible pyrolysis mechanism of TPN resin under non-oxidizing gaseous environment was proposed. The results of this study provide the useful information for designing the molecular structure of l-tyrosine-based polymers which possessing high thermal stability. 相似文献