Effects of base catalysis on the product distribution from pyrolysis of woody biomass in the presence of water

Previous work has shown that woody biomass can generate oil-like products during hydrous pyrolysis. However, the yield of extractable organic matter is rather small, and the proportion of coke is high. In order to increase the oil yield and decrease the coke generation, experiments with added base catalysts have been made. NaOH was chosen as the catalyst. Experimental design is used to investigate the effects of variable experimental conditions during pyrolysis. The results are compared with similar experiments without a catalyst, and show a general decrease in coke formation and increase in the extractable organic matter with a dominance of polar compounds. The variable with the largest effect on yields is the amount of water, while pyrolysis temperature and the amount of starting material have minor effects.     

The degree of oxidation of iron in synthetic iron-magnesian biotites

Summary Chemical analytical and pyrolytical methods have been used to study the Fe⁺²/Fe⁺³ ratios and dehydroxylation reactions in synthetic biotites. It has been found for the biotites with Fe/(Fe + Mg) of 20 to 70 mole % that the oxidation degree decreases from 26 to 16% with increasing iron. Based on the measured amounts of water and hydrogen released during pyrolysis it is inferred that the deprotonization is a dominant reaction at low temperatures (T 600°C), accompanied by dehydration as the temperature increases. Depending on the composition, a complete dehydroxylation takes place at T 900 °C, and the measured amount of water corresponds to the iron oxidation degree in the starting samples. The results of this study have important implications with respect to determination of the formation conditions of biotite-bearing rocks, and also for improvement of the techniques for determination of different valence of iron and water.

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Le degré d'oxidation du fer en biotites synthétiques contenants le fer et le magnésium

Résumé Des méthodes chimiques et pyrolitiques ont été utilisées pour l'étude des rapports Fe⁺²/Fe⁺³ et de la réaction de la déhydroxilation en biotites synthétiques. On a trouvé pour les biotites avec Fe/(Fe + Mg) de 20-70 mole % que le degré d'oxidation décroît à partir de 26 jusqu'à 16% pendent que le contenu du fer s'accroît. Sur la base de la quantité d'eau et hydrogène liberée pendant la pyrolyse, on infère que la déprotonisation est une réaction dominante à températures basses (T = 600°C), mais quand la température s'accroît, la déprotonisation est accopagnée de la déhydratation. Dépendant de la composition il y a une déhydroxilation complète à T = 900°C, et la quantité de l'eau mesurée correspond au degré d'oxidation du fer dans les specimens initials. Les résultats de cette étude infuencent la détermination des conditions de formation des roches contenantes biotite et aussi l'amélioration des techniques de la détermination du fer de valences différentes et de l'eau.

     

The kerogen type, depositional environment and maturity, of the Irati Shale, Upper Permian of Paraná Basin, Southern Brazil

Two samples from the upper and lower horizons of the Irati oil shale of the Paraná Basin, Brazil were sampled in a single borehole, and analysed using organic petrography and geochemistry. The results are interpreted in terms of the kerogen type, maturity and depositional environment of the two horizons.Organic petrography shows the oil-shales to be composed of a mineral groundmass, mainly clay minerals, carbonate and pyrite, associated, and sometimes impregnated, with fluorescing organic material and disseminated phytoclasts. Humic material is fairly rare and mostly present as very small particles. The liptinitic particles are mostly alginite (A and B), sporinite and more rarely resinite. Reflectance measurements (upper seam = 0.34% R₀; lower seam = 0.40% R₀) indicate an equivalent rank of lignite/sub-bituminous coal (ASTM), i.e. immature with respect to oil and gas generation. Different organic geochemical methods (Rock-Eval pyrolysis, solvent extraction, GC and GC-MS) demonstrate both samples to be immature, rich oil-shales (100–114 kg/ton) containing Type I kerogen, of a dominantly bacterially-degraded algal origin deposited in a lacustrine environment. The presence of Botryococcus suggests deposition under fresh/brackish water conditions.A tentative interpretation of the extract and vitrinite reflectance data suggests a maximum paleo-burial of between 1.3 and 2.8 km for the analysed section of the Irati Formation.     

六盘山东麓地区岩溶地质特征分析

六盘山东麓地区岩溶具有我国北方岩溶的基本特点,地表岩溶形态以常态山和干谷为主,地下岩溶以溶隙为主。该区岩溶发育程度除受岩性条件决定外,同时还受构造因素和水动力条件的控制。在分析影响岩溶发育因素的基础上,指出了岩溶在区域上的分布规律,同时划分了岩溶含水岩组,并论述了各岩组的富水性。     

沥青成因及反映的油气成藏过程

地质体中沥青按沉积有机质的不同演化路径分为原生和次生沥青,次生沥青由于经历的地质作用不同,又分为生物降解水洗氧化和热裂解成因两种类型,本文重点讨论热裂解成因沥青。热裂解成因沥青是干酪根在生油窗阶段生成的原油,进一步深埋温度增高,达到原油裂解的热动力学条件,裂解生成天然气后的残余物。干酪根热降解生成的原油有聚集型、源内分散型、源外分散型三种赋存方式,裂解分别对应形成三种赋存状态的沥青。通过四川盆地13口井60余块岩芯样品热裂解成因沥青从宏观到微观不同尺度的研究,沥青体积含量0.1%～15%,形态有条带状、片状、块状、粉末状;赋存方式有裂缝(区域沟通油源的断层)、层理面、微裂隙、原生、次生溶蚀孔、洞等;赋存岩石有粗晶、中—细晶白云岩。伴生的包裹体发育丰富,可区分出孔洞方解石早期和晚期充填、白云石次生加大边、孔洞方解石微裂隙等方式,还有富沥青质的包裹体。颜色透明无色—淡褐色、无色—灰色、深灰色、深褐色等。常量和微量元素含量及不同比值反映了沥青的氧化还原特征。含烃包裹体均一温度从90～220℃,综合记录了油气生成演化的整个过程,以及经历的异常热作用;同一样品加大边中包裹体温度分布范围普遍比较宽...     

Oil-generating coals of the San Juan Basin, New Mexico and Colorado, U.S.A.

Coal beds of the Upper Cretaceous Fruitland Formation in the San Juan Basin of northwestern New Mexico and southwestern Colorado have significant liquid hydrocarbon generation potential as indicated by typical Rock-Eval Hydrogen Indexes in the range of 200–400 mg hydrocarbon/g organic carbon (type II and III organic matter). Small, non-commercial quantities of oil have been produced from the coal beds at several locations. The oils are characterized by high pristane/phytane (ca 4) and pristane/n-C₁₇ ratios (ca 1.2), abundant C₂₁₊ alkanes in the C₁₀₊ fraction with a slight predominance of odd carbon-numbered n-alkanes, abundant branched-chain alkanes in the C₁₅₊ region, and a predominance of methylcyclohexane in the C₄----C₁₀ fraction. The oils are indigenous to the Fruitland Formation coals and probably migrated at thermal maturities corresponding to vitrinite reflectance values in the range 0.7–0.8%. Although the oils found to date are not present in commercial amounts, these findings illustrate the potential of some coals to generate and expel oil under conditions of moderate thermal heating.     

Geochemical characteristics of pyrolysis gas from epimetamorphic rocks in the northern basement of Songliao Basin,Northeast China

The Xushen gas field,located in the north of Songliao Basin,is a potential giant gas area for China in the future.Its proved reserves have exceeded 1000×10 8 m 3 by the end of 2005.But,the origin of natural gases from the deep strata is still in debating.Epimetamorphic rocks as a potential gas source are widely spreading in the northern basement of Songliao Basin.According to pyrolysis experiments for these rocks in the semi-confined system,gas production and geochemistry of alkane gases are discussed in this paper.The Carboniferous-Permian epimetamorphic rocks were heated from 300℃to 550℃,with temperature interval of 50℃.The gas production was quantified and measured for chemical and carbon isotopic compositions.Results show thatδ13C 1 is less than?20‰,carbon isotope trend of alkane gas isδ13C 1 <δ13C 2 <δ13C 3 orδ13C 1 <δ13C 2 >δ13C 3 ,these features suggest that the gas would be coal-type gas at high-over maturity,not be inorganic gas with reversal trend of gaseous alkanes (δ13C 1 >δ13C 2 >δ13C 3 ).These characteristics of carbon isotopes are similar with the natural gas from the basin basement,but disagree with gas from the Xingcheng reservoir.Thus,the mixing gases from the pyrolysis gas with coal-typed gases at high-over maturity or oil-typed gases do not cause the reversal trend of carbon isotopes.The gas generation intensity for epimetamorphic rocks is 3.0×10 8 ―23.8×10 8 m 3 /km 2 ,corresponding to Ro from 2.0%to 3.5%for organic matter.     

Effect of artificial maturation on carbazole distributions, as revealed by the hydrous pyrolysis of an organic-sulphur-rich source rock (Ghareb Formation, Jordan)

Hydrous pyrolysis experiments were performed on the Ghareb Formation (Upper Cretaceous, Jordan), a carbonate- and organic-rich (TOC 19.6%) source rock, using a temperature range of 200 to 360°C (72 h). The original sediment contains only low amounts of carbazoles, (maximum 2.2 μg/g bitumen for 1-methylcarbazole). With increasing thermal maturation, intense generation begins at temperatures only in excess of 300°C, reaching a maximum at 360°C. Likewise, during natural maturation, generation occurs at later stages of maturity (e.g. for Tithonian source rocks at >0.81% R_r and for Posidonia Shale at >0.88% R_r). Some isomeric changes during hydrous pyrolysis do not resemble those in nature whereas others do. The relative abundances of selected C₁- and C₂-alkylcarbazoles on ternary diagrams reveal differences, whereas the benzo[a]carbazole/benzo[a]carbazole+benzo[c]carbazole ratio is closely similar. The latter result supports the contention that maturation plays a key role in controlling carbazole distributions in source rocks. However, the results for alkylcarbazoles, especially the C₂-carbazoles, are not easy to interpret.     

水合氧化锆吸附硼的研究

详细地研究了硼在水合氧化锆吸附剂上的吸附行为。研究结果表明，水合氧化锆的吸硼速率较快，２ｈ可完全达平衡，且吸附可用Ｆｒｅｕｎｄｌｉｃｈ等温吸附线很好地拟合。被吸附的硼易被碱液洗脱，通过水合氧化锆上硼的“吸附－脱附循环”研究，表明该吸附剂的吸附性能好，再生能力强，循环使用寿命长，是一种很有价值的高效脱硼吸附剂。     

Crystal structure and compression of an iron-bearing Phase A to 33 GPa

Fe-bearing dense hydrous magnesium silicate Phase A, Mg_6.85Fe_0.14Si_2.00O₈(OH)₆ has been studied by single-crystal X-ray diffraction at ambient conditions and by high-pressure powder diffraction using synchrotron radiation to 33 GPa. Unit cell parameters at room temperature and pressure from single crystal diffraction are a=7.8678 (4) Å, c=9.5771 (5) Å, and V=513.43 (4) ų. Fitting of the P–V data to a third-order Birch-Murnaghan isothermal equation of state yields V ₀=512.3 (3) ų, K _T,0=102.9 (28) GPa and K′=6.4 (3). Compression is strongly anisotropic with the a-axes, which lie in the plane of the distorted close-packed layers, approximately 26% more compressible than the c-axis, which is normal to the plane. Structure refinement from single-crystal X-ray intensity data reveals expansion of the structure with Fe substitution, mainly by expansion of M-site octahedra. The short Si2–O6 distance becomes nearly 1% shorter with ~2% Fe substitution for Mg, possibly providing additional rigidity in the c-direction over the Mg end member. K _T obtained for the Fe-bearing sample is ~5.5% greater than reported previously for Fe-free Phase A, despite the larger unit cell volume. This study represents a direct comparison of structure and K _T–ρ relations between two compositions of a F-free dense hydrous magnesium silicate (DHMS) phase, and may help to characterize the effect of Fe substitution on the properties of other DHMS phases from studies of the Fe-free end-members.