油页岩颗粒的热解模型

以实验为依据,分析了油页岩的热解机理及特性,并充分考虑了油页岩中挥发分在整个热解过程的作用,在此基础上建立了与油页岩固有热解特性相适应的热解模型。在能量方程中考虑了油页岩挥发分的热解反应吸热量及其挥发分的释放对油页岩固体颗粒质量的影响,并根据油页岩的热解特性,采用分阶段模型来描述油页岩的热解过程,以减小一步本征动力学方程带来的较大误差,还对模型进行了实验验证。     

Pyrolysis kinetics for Green River oil shale from the saline zone

The nature of the organic and mineral reactions during the pyrolysis of Saline-zone Colorado oil shale containing large amounts of nahcolite and dawsonite has been determined. Results reported include a material-balanced Fischer assay and measurements of gas evolution rate of CH₄, C₂H_x, H₂, CO and CO₂, Stoichiometry and kinetics of the organic pyrolysis reactions are similar to oil shale from the Mahogany zone. X-ray diffraction and thermogravimetric analysis results are used to help determine the characteristics of the mineral reactions. Kinetic expressions are reported for dawsonite decomposition, and it is demonstrated that the temperature of dolomite decomposition is substantially lower than for Mahogany-zone shale because of the presence of the sodium minerals.     

Pyrolysis of Tertiary oil shale by a dolerite intrusion,Stuart Deposit,Queensland, Australia

The mid to late Eocene oil shale sequence of the Stuart Deposit, eastern Queensland, Australia, has been intruded by an alkali dolerite laccolith. The dolerite pyrolysed the intruded sediments with the observed aureole up to 68 m thick. Petrographic studies of samples from five drill holes that intersected the aureole showed that vitrinite reflectance near the top of the aureole generally decreases with depth but closer to the contact vitrinite reflectance rapidly increases. The lowest reflectance values are associated with a zone of bitumen, derived from the thermal alteration of alginite, in each of the five drill holes. The decrease in vitrinite reflectance is accompanied by a decrease in the fluorescence intensity of alginite and a shift in fluorescence colour towards the red end of the spectrum. In the zone characterized by the rapid increase in vitrinite reflectance, the alginite was pyrolysed and pyrolytic carbon formed.     

Pyrolysis with partial combustion of oil shale fines in a spouted bed

Pyrolysis with partial combustion of oil shale fines from the Irati Formation in Brazil has been investigated in a 30 cm diameter spouted bed reactor. Experiments were carried out at atmospheric pressure and temperatures between 450 and 600°C. The oi] shale particle size was less than 6.35 mm. Spouting gas temperatures ranged from 20 to 565°C. Three inlet gas pipe diameters and two spouted bed heights were studied. Operation of the process was found to be stable over a wide range of test conditions. Results are presented for oil and gas quality, efficiency of retorting and overall performance of the plant.     

Determination of polar compounds in Rundle shale oil

The acidic and basic components of three distillate fractions (light, middle and heavy) of shale oil from the Rundle (Queensland, Australia) deposit were selectively extracted. Capillary gas chromatography/mass spectrometry was used to identify individual polar components. The major nitrogen-containing polar compounds in the light fraction were alkyl-substituted pyridines, and substituted quinolines were more abundant in the middle and heavy fractions. Significant quantities of pyrrole derivatives were also identified. Small quantities of anilines and benzoquinolines made up the remainder of the bases. The oxygen-containing compounds were mainly phenolic in nature; alkyl-substituted phenols were the major components, but significant quantities of naphthols and traces of fluorenols were identified.     

小颗粒窑街油页岩流化床热解提油特性研究

在电炉加热流化床热解反应器上,进行了小颗粒窑街油页岩热解提油实验,研究了热解温度和固相停留时间对热解提油特性的影响,并深入分析比较不同条件制得焦油的品质。结果表明:热解反应进程、固液气三态产物分布和焦油品质主要受热解温度影响,受固相停留时间的影响相对较小。在500—600℃范围内,随着热解温度上升,热解反应从热分解阶段过渡到热缩聚阶段,液体产率和焦油品质均先上升后下降、并在550℃均达到最佳,此时液体产率为6.5%,一级热解液体产物中焦油的饱和分和芳香分质量分数分别达到30.0%和29.4%。在15—45min的固相停留时间范围内,适当延长固相停留时间有利于物料中可热解成分的析出,液体产率增大,焦油含中低温馏分及饱和分和芳香分的质量分数先增大、30 min后基本不变。     

Selective removal of nitrogen compounds from shale oil

A solid extraction process for selectively removing nitrogen from alternative refinery feedstock has been developed. It has been demonstrated that solid CuCl₂ · xH₂O can reduce the nitrogen content of shale oils to acceptable levels for some refineries. In a simple single-stage process, the nitrogen content was reduced by more than 85% to levels below 0.2 wt%. The solid extraction process was remarkably selective and produced high oil recovery yields corresponding to ≈98% of the theoretical limit. Experiments with model systems have shown complete selectivity for the nitrogen compounds and have demonstrated that the entire bulk of the solid is involved in the extraction process. Many other solids have been shown to be effective, namely transition metal halides, nitrates, sulphates, acetates, fluoroborates, and phosphates.     

Pyrolysis behaviour of Australian oil shales in a fluidized bed reactor and in a material balance modified Fischer assay retort

The pyrolysis behaviour of several Australian oil shales was determined using the material balance modified Fischer assay and a bench-scale fluidized bed pyrolysis reactor, with nitrogen or steam as the sweep gas. The assay oil yield, which ranged from 5.3 to 15.7 wt% of the dry shale, did not correlate well with the organic carbon contents of the shales. However, under both assay and fluidized bed pyrolysis conditions, a shale of high kerogen H/C had high organic carbon conversions to oil. Compared with the Fischer assay, nitrogen pyrolysis gave 7 ± 4 wt% more oil for the shales studied, and steam pyrolysis gave 15 ± 4 wt% more oil for all shales except one, which showed a 35 wt% increase in oil yield. However, the oils from both nitrogen and steam pyrolysis had lower H/Cs, higher sulphur and nitrogen contents, and more high boiling point fractions than those from the Fischer assay. Nitrogen pyrolysis oils were of higher quality than those produced by steam pyrolysis. With steam as the sweep gas, much more hydrogen and hydrogen sulphide were produced for all shales; in most cases, there was also more carbon monoxide and less hydrocarbon gases.     

Effect of lignite addition and steam on the pyrolysis of Turkish oil shales

Steam was found to be a more effective sweep gas than nitrogen at low velocities in fixed-bed pyrolysis of Goynuk oil shale but, at higher velocities and in fluidized-bed pyrolysis, the differences were considerably less marked. Relatively small but significant synergistic effects were observed between lignites and the two oil shales investigated — Goynuk and Seyitomer — under static retorting conditions. These effects were more pronounced with large concentrations of oil shales but disappeared in fluidized-bed pyrolysis, where conversions are considerably higher because mass transfer limitations largely disappear.     

Gas evolution during pyrolysis of various Colorado oil shales

Rates of evolution of C0₂, CO, H₂, CH₄ and the C₂ and C₃ hydrocarbons during the pyrolysis of seven Colorado oil shales have been measured. These shales, which are from various depths at two different sites, yield 34–255 ¦ of oil per tonne raw shale (9–61 US gal of oil per short ton raw shale) and linear heating at a rate of 2°C min⁻¹ was used for the retorting of all samples. The objective of the study is to monitor variations in gas evolution from shales of different organic content and from various stratigraphic and areal locations. Comparisons between shales from each site are made together with correlations with data from Fischer assays. A kerogen concentrate (mineral fraction removed by HCl-HF treatment) and retorted shale from a Fischer assay are also included. The ability of a kinetic model due to Campbell et al. to predict gas evolution is tested and it is found necessary to modify slightly some of the stoichiometric coefficients to obtain good agreement. The resultant kinetic model should adequately describe the gas and oil evolution behaviour of shale from the upper portion of the Green River formation.     

Rapid pyrolysis of brown coal and oil shale

A brown coal, peat and oil shale were subjected to a rapid pyrolysis process and medium-heat-value gases together with tar were collected. The char residue was of high activity and suitable for gasification to create a two-stage gasification system. The coal-tar is used for manufacturing liquid fuels and chemicals.     

Pyrolysis/g.c. of oil shales and coal

Pyrolysis studies of coal, kerogen and oil shales were carried out in a microprobe connected to a gas Chromatograph, in the temperature range 620–1160 °C. It was shown that the CO₂ evolved in the decomposition of the carbonates in the shales participates in the reaction and complete volatilization of the organic matter takes place. The product distribution can also be changed by the use of a nickel catalyst in the pyrolytic tube.     

Isothermal oil shale pyrolysis. 1. Oil generation and composition at various pressures

A rich (250 I (59 gal) per ton) Green River oil shale was retorted in a helium atmosphere. Isothermal retort experiments from 375 to 500 °C were carried out at 78 kPa and 765 kPa. Oil was collected as a function of time and a comprehensive analytical procedure was developed and utilized to determine seven oil fractions: straight-chain pentane de-asphaltened dry whole oil (DDWO); solids; saturates (S); aromatics (A); olefins (0); ‘weak’ polars (WP); and polars (P). The objectives of this work were: (a) to develop data to show oil generation and composition at different temperatures and pressures under isothermal, isobaric conditions; (b) to determine the effect of pressure on total oil yield and product-oil composition. Total oil yield was reduced as the pressure was increased. Much of this reduction can be accounted for in the reduced amounts of polar compounds formed at higher pressure because the polar fraction comprises approximately 35–45 wt% of the DDWO. In general, the amounts of aromatics present increase, the amounts of olefins decrease, and the amounts of saturates and ‘weak’ polar compounds remain relatively constant with increased system pressure.     

Chemical depolymerization of oil shale

The chemical structure of the organic matter from Krassava oil shale has been investigated by means of chemical degradation with metallic sodium in liquid ammonia and with phenol in the presence p-toluenesulphonic acid. The former reaction yielded 20 wt% of pyridine-soluble material and the latter ≈ 65 wt%. Extensive depolymerization of the oil shale was achieved by a combination of both methods in which case the solubility of the organic matter was increased to 85–95 wt%. The characterization of soluble and insoluble products by pyrolysis g.c. and elemental analysis indicated that aliphatic chains were prevalent in the organic matter of the Krassava oil shale.     

Study of the pyrolysis of Maoming oil shale lumps

Pyrolysis experiments on Maoming oil shale lumps (10–60 mm in diameter) were carried out with the aid of large-particle thermogravimetric analysis apparatus at constant heating rates of 1, 2 and 5 °C min⁻¹. A pyrolysis kinetic model was developed which took into account both the pyrolysis reaction and intraparticle heat transfer. Oil shale pyrolysis kinetic parameters were then determined on the basis of experimental data concerning weight loss, shale oil production, gas evolution and intraparticle temperature distribution versus time, by using the developed model. Furthermore, the effects of variables (e.g. temperature, lump size, heating rate) on oil shale pyrolysis were assessed during experimentation. It is found that model predictions agree reasonably well with experimental data.     

微波功率对油页岩热解的影响

对甘肃油页岩进行了微波热解实验研究,考察了油页岩在微波场中的升温特性及功率对页岩油、半焦、干馏气产率和组成的影响。结果表明：在微波场中油页岩干馏终温可达800℃以上;不同功率下干馏气组成不同,在480 W时干馏气中有效组分（H2＋CH4＋CO）达55%以上;随着功率的增大,半焦产率逐渐减小;页岩油产率随功率先增加后减小,在480 W时达到最大值13.5%;而干馏气产率随功率逐渐增大,在480 W时可达10%。     

Chemical transformations during pyrolysis of Rundle oil shale

Rundle shale (Queensland, Australia) was pyrolysed at 12.5 K min⁻¹ to 350–500 °C for 10–240 min. The structures of the liquid products and pyrolysis residues were investigated by a number of n.m.r. spectroscopic techniques including cross-polarization and dipolar dephasing. N.m.r. provided a simple method for detecting nitrile carbon and measuring terminal and internal olefinic hydrogen in shale oil. It was found that the ratio of terminal olefinic hydrogen to internal olefinic hydrogen in shale oil increases by a factor of three over the range 350–500 °C. Moreover, the results suggest that aromatic rings in Rundle shale residues are not highly substituted and hence that aromatic ring condensation reactions are not important during pyrolysis. From elemental, yield and n.m.r. data, the conversion of aliphatic carbon to aromatic carbon during pyrolysis was found to be as high as 25% at 500 °C.     

Geochemical characterization of solid residues, bitumen and expelled oil based on steam pyrolysis experiments from Irati oil shale, Brazil: A preliminary study

Steam pyrolysis experiments were performed on immature samples from the Irati oil shale, Paraná Basin, Brazil, using a maximum temperature of 350 °C with up to 98 h exposure time at that temperature. The objectives were to study geochemical and petrographical changes in the source material during stepwise increase in maturity, in steam conditions, comparing the properties of expelled oil with the bitumen retained in the solid residue after experimentation.Petrographical and geochemical parameters such as vitrinite reflectance and T_max, indicated an increase in maturity related to the exposure time of the organic matter to the maximum temperature. However, biomarker ratios such as 22S/(22S + 22R) C₃₁ and C₃₂ homohopanes, 20S/(20S + 20R) and αββ/(αββ + ααα) C₂₉ sterane, which are considered to be indicators of organic matter maturity levels, did not reach their equilibrium values. Some biomarkers frequently used as indicators of specific sources and/or paleoenvironments of deposition such as hopane/sterane ratio, and the concentrations of C₂₇ and C₂₉ steranes showed significant variations related to the stage of maturity. Based on the evaluation of Rock-Eval parameters, the transformation ratios in steam pyrolysis conditions reached levels higher than 80% in samples having 9 and more hours of exposure time to maximum temperature. Bitumen was found to be enriched in components of heavier molecular weight (resins and asphaltenes), whereas the expelled oils contained higher quantities of aliphatic and aromatic components. At relatively low maturity levels the n-alkane distribution of expelled oils indicate a somewhat higher maturity level when compared to the n-alkane distribution of the bitumen retained in the source rock, whereas at higher maturity levels the n-alkane distribution for the expelled oil and for the bitumen is very similar.     

Trace metal composition of Green River retorted shale oil

Crude shale oils from an aboveground and two in-situ retorting processes were characterized for 26 trace element constituents. The shale oils were pyrolysed from Green River Formation oil shale by pilot plant or semiworks-sized facilities. Trace elements were resolved into those predominantly associated with suspended shale fines or emulsified water, and those more intimately associated with the shale oil matrix. The abundance of the metals As, Co, Fe, Hg, Mo, Ni, Sb, Se, V and Zn were quantified in whole and fractionated shale oil samples; the possible chemical nature of several metals is discussed. Based on the shale oils examined, the following observations were noted: the shale oils contained moderately high levels of Fe (33–63 ppm) and As (9.3–29 ppm), and lower quantities of Co, Mo, Ni, Se and Zn (≈1–10 ppm); most trace metals were associated with asphaltene or resin components; relative to reported mean values for petroleum, the As, Co, Fe, Mo and Se were more prevalent in Green River shale oil; in-situ retorting processes appeared to introduce Mo into the product shale oil.     

油页岩低温干馏过程的Aspen Plus模拟

利用Aspen Plus系统流程模拟软件模拟油页岩的低温干馏,并按照含油率测定实验工况来设置系统流程,以探讨将Aspen Plus应用于油页岩热解领域的可行性。针对吉林地区桦甸一矿4层和二矿11层的油页岩试样进行模拟,并将所得的含油率、含水率、半焦产率、干馏气体产率及半焦中各元素含量等模拟数据与实验值进行对比分析,模拟结果与实测值间的误差均控制在合理范围之内。对比结果表明,系统流程的建模及物性参数设置是正确合理的,可为后期构建完整的油页岩综合利用系统提供参考。