吐哈盆地低熟气评价的化学动力学方法及其应用

针对目前尚无公认的有效方法评价低熟气生成量的难题,本文从低熟气的（低温）热成因机理出发,认为被广泛、成功应用于成熟的热成因天然气生成量评价的化学动力学理论仍然应该是评价低熟气生成量的有效方法。在此基础上,建立并标定了吐哈盆地代表性泥岩、煤岩干酪根成气的化学动力学模型,与可能部分成为低熟气先质的非烃、沥青质的化学动力学模型一起,构成了评价低熟气生成量的方法。标定结果表明,盆地内有机质成气的平均活化能低于其成油的活化能,而且成气过程中低活化能组分的含量也高于成油过程。这可能正是吐哈盆地的有机质在大量生油之前的低成熟阶段,能开始规模性地生成低熟气、从而导致工业性的低熟气聚集的内因所在。应用表明,吐哈盆地低熟气的总生成量可观,达到632．15×10^11 m^3,而且生气强度较高,最高达到100×10^8m^3／km^2以上。吐哈盆地低熟气资源量约为3．16×10^11～12．62×10^11 m^3。可见,盆地内低熟气具有可观的勘探潜力。本文所建立的方法应该可被推广应用到其他含低熟气盆地的低熟气的评价当中。     

铅在高岭石表面的解吸动力学

经过酸性条件下（pH=3.1)Pb(Ⅱ）高岭石表面解吸动力学的研究，发现解吸反应与吸附反应动力学相似，也是一个二阶段的过程，即初始的快速解吸之后伴随着一个缓慢的释放过程。在快速解吸阶段，7min内解吸量即已达到41％。吸附铅没有完全解吸，有近38％残留在高岭石表面，即解吸和吸附过程不是完全可逆的。解吸过程可以用扩展Elovich方程、Elovich方程、双常数方程和一级扩散方程较好地似合。     

A study on the adsorption of chromium on laterite from Guizhou Province,China

The adsorption behaviors of Cr(VI) on laterite from Guizhou Province were studied in this paper, and the adsorption mechanism was discussed as well. Results showed that different mineral compositions in the laterite would cause differences in the capacity of laterite to absorb Cr(VI). Gibbsite, iron oxide minerals and non-crystalloids are the main contributors to enhancing the capacity of laterite to absorb Cr(VI). The pH of the solution is an important factor affecting the adsorption of Cr(VI) on laterite. Acidic environment (pH=2–5) is favorable to the adsorption of Cr(VI). The amount of adsorbed Cr(VI) decreases with increasing pH of the solution. With increasing initial concentrations of Cr(VI), the amount of adsorbed Cr(VI) increases first, and then decreases. The optimal adsorption concentration of Cr(VI) on laterite is 250 μg/mL. The adsorption of Cr(VI) on laterite is a rapid process, about 80% Cr(VI) will be adsorbed within 2 hours. And the adsorption of Cr(VI) on kaolinite is a slow process.     

光催化降解乐果的动力学研究

采用30 W石英紫外灯作为光源,研究了乐果在二氧化钛悬浮体系中光催化降解反应的动力学规律。考察了乐果起始浓度、TiO2用量、溶液pH值及温度对乐果光催化降解速率的影响,结果表明,乐果光催化降解符合表观零级动力学规律。由于速率常数k与乐果起始浓度有关,表明乐果光催化降解反应不是一个简单的零级反应。     

Kinetic study of the dehydroxylation of chrysotile asbestos with temperature by in situ XRPD

 The kinetics of the dehydroxylation of chrysotile was followed in situ at high temperature using real-time conventional and synchrotron powder diffraction (XRPD). This is the first time kinetics parameters have been calculated for the dehydroxylation of chrysotile. The value of the order of the reaction mechanism calculated using the Avrami model indicates that the rate-limiting step of the reaction is a one-dimensional diffusion with an instantaneous nucleation or a deceleratory rate of nucleation of the reaction product. Hence, the rate-limiting step is the one-dimensional diffusion of the water molecules formed in the interlayer region by direct condensation of two hydrogen atoms and an oxygen atom. The calculated apparent activation energy of the reaction in the temperature range 620–750 °C is 184 kJ mol⁻¹. The diffusion path is along the axis of the fibrils forming the fibers. The amorphous or short-range ordered dehydroxylate of chrysotile is extremely unstable because forsterite readily nucleates in the Mg-rich regions. Moreover, it is less stable than the dehydroxylate of kaolinite, the so-called metakaolinite, which forms mullite at about 950 °C. This difference is interpreted in terms of the different nature of the two ions Mg²⁺ and Al³⁺ and their function as glass modifier and glass-forming ion, respectively. Received: 10 April 2002 / Accepted: 7 January 2003 Acknowledgements This work is part of a COFIN project (04 Scienze della Terra, NR 17, 2000) supported by MURST. Dr Dapiaggi is kindly acknowledged for help during the data collection at the Dipartimento di Scienze della Terra, University of Milan.     

Characterization of Regional Combustion Efficiency using ΔXCO: ΔXCO2 Observed by a Portable Fourier-Transform Spectrometer at an Urban Site in Beijing

Measurements of column-averaged dry-air mole fractions of carbon dioxide and carbon monoxide, CO₂ (XCO₂) and CO (XCO), were performed throughout 2019 at an urban site in Beijing using a compact Fourier Transform Spectrometer (FTS) EM27/SUN. This data set is used to assess the characteristics of combustion-related CO₂ emissions of urban Beijing by analyzing the correlated daily anomalies of XCO and XCO₂ (e.g., ΔXCO and ΔXCO₂). The EM27/SUN measurements were calibrated to a 125HR-FTS at the Xianghe station by an extra EM27/SUN instrument transferred between two sites. The ratio of ΔXCO over ΔXCO₂ (ΔXCO:ΔXCO₂) is used to estimate the combustion efficiency in the Beijing region. A high correlation coefficient (0.86) between ΔXCO and ΔXCO₂ is observed. The CO:CO₂ emission ratio estimated from inventories is higher than the observed ΔXCO:ΔXCO₂ (10.46 ± 0.11 ppb ppm^?1) by 42.54%–101.15%, indicating an underestimation in combustion efficiency in the inventories. Daily ΔXCO:ΔXCO₂ are influenced by transportation governed by weather conditions, except for days in summer when the correlation is low due to the terrestrial biotic activity. By convolving the column footprint [ppm (μmol m^–2 s^–1)^–1] generated by the Weather Research and Forecasting-X-Stochastic Time-Inverted Lagrangian Transport models (WRF-X-STILT) with two fossil-fuel emission inventories (the Multi-resolution Emission Inventory for China (MEIC) and the Peking University (PKU) inventory), the observed enhancements of CO₂ and CO were used to evaluate the regional emissions. The CO₂ emissions appear to be underestimated by 11% and 49% for the MEIC and PKU inventories, respectively, while CO emissions were overestimated by MEIC (30%) and PKU (35%) in the Beijing area.     

Autoxidation of N(III), S(IV), and other Species in Frozen Solution – A Possible Pathway for Enhanced Chemical Transformation in Freezing Systems

The chemistry of glycolaldehyde (hydroxyacetaldehyde) relevant to the troposphere has been investigated using UV absorption spectrometry and FTIR absorption spectrometry in an environmental chamber. Quantitative UV absorption spectra have been obtained for the first time. The UV spectrum peaks at 277 nm with a maximum cross section of (5.5± 0.7)×10^–20 cm² molecule^–1. Studies of the ultraviolet photolysis of glycolaldehyde ( = 285 ± 25 nm) indicated that the overall quantum yield is > 0.5 in one bar of air, with the major products being CH₂OH and HCO radicals. Rate coefficients for the reactions of Cl atoms and OH radicals with glycolaldehyde have been determined to be (7.6± 1.5)×10^–11 and (1.1± 0.3)×10^–11 cm³ molecule^–1 s^–1, respectively, in good agreement with the only previous study. The lifetime of glycolaldehyde in the atmosphere is about 1.0 day for reaction with OH, and > 2.5 days for photolysis, although both wet and dry deposition should also be considered in future modeling studies.     

Kinetic study of the hydrocarbon generation from Upper Paleozoic coals in Ordos Basin

When organic matter during geological processes is affected by a variety of factors such as paleotemperature, and time, complicated chemical reactions will occur, finally resulting in the generation of petroleum and natural gas. These reactions leading to…