Application of the rotating disk method to the study of bitumen dissolution into organic solvents

The rotating disk system is demonstrated as a tool for performing studies of the dissolution rate of bitumen into organic solvents. Mass transfer coefficients to the rotating disk are constant in position and time can be made comparable to coefficients for sand particles in agitated liquids by adjusting the rotation rate. Data is presented for bitumen dissolution into pentane, hexane, heptane, toluene and oleic acid. Increasing the level of dissolved bitumen in the solvent decreases the bitumen dissolution flux primarily due to the increase in solvent viscosity.     

DISSOLUTION KINETICS OF PHOSPHATE ORE IN ACIDIC SOLUTIONS

1 INTRODUCTIONIn the wet processes of industrial phosphoric acid production,sedimentary or francolitephosphate ore dissolves in mineral acid.If the acid is sulphuric acid,which is a classic wetprocess,the crystallization of calcium sulphate occurs.The rate of crystallization is normallyconsidered quite slower than that of dissolution.So only few publications have devoted     

Dissolution Rate of BTEX Contaminants in Water

The BTEX group of contaminants consists of benzene, ethylbenzene, toluene, and three isomers of xylene. The dissolution rate, solubility, slick area and mass transfer coefficient were examined for the BTEX. The release of BTEXs into the environment is influenced by their fate and transport mechanisms. Thus, the fate and transport mechanisms are affected by the contaminant characteristics, which vary with the different BTEX compounds. A comprehensive model has been developed to simulate the molecular dissolution rate of BTEX contaminants in a natural water stream. The developed model modifies the work of Cohen et al. (1980) by considering the physicochemical properties of the BTEX compounds and physical processes relevant to the spreading of contaminants in the sea. The model shows that Benzene with greater solubility in water and dissolution coefficient has the largest dissolution rate while o‐xylene with the biggest density has the lowest dissolution rate because of its low fraction. The benzene dissolution rate is about 2.6, 20.6 times that of Toluene, ethylbenzene, respectively, but with a varying proportion with the xylenes. The model has been validated against the theories of mass transfer rate at the surface at appropriate surface area. The developed model can be found useful in prediction and monitoring the dissolution rate of contaminants in soil and water systems.     

鄂尔多斯盆地旬邑探区延长组储层特征和开发效果

鄂尔多斯盆地旬邑探区延长组开发潜力较大,储层特征的定量评价对准确预测开发效果具有指导意义。选取延长组6段（长6）和延长组8段（长8）储层典型岩心进行实验分析,核磁共振实验结果显示长6和长8储层孔喉分布特征较为单一,不进行离心实验的情况下可利用核磁共振渗透率和T₂几何平均值计算可动流体百分数。恒速压汞实验结果表明,孔隙比喉道发育均匀,未开展其他实验的情况下可利用恒速压汞实验计算孔隙度。通过建立核磁共振和恒速压汞耦合求取完整孔喉半径分布的方法,确定了旬邑探区延长组长6和长8储层的表面弛豫率为0.15 μm/ms。核磁共振孔喉半径分布的计算结果显示,长6储层孔喉半径分布范围为0.01~433.10 μm,长8储层孔喉半径分布范围为0.01~403.91 μm,长6储层孔喉发育比长8储层均匀。通过定义拟粒间孔和拟溶蚀孔,拟溶蚀孔绝对体积占比揭示,长8储层渗流能力强于长6储层。建立了"拟溶蚀孔+含油饱和度"方法预测开发效果,分析认为拟溶蚀孔对试油产量的影响更大,进一步揭示了旬邑探区长8储层整体开发效果好于长6储层。     

硅酸盐矿物溶解动力学及其对滑坡研究的意义

硅酸盐是地壳岩石最主要的造岩矿物,表生条件下硅酸盐矿物的溶解是普遍的。实验室条件下,硅酸盐矿物存在非线性溶解现象,稳定态溶解速率一般为10-12～10-8 mol/(m2·s),而组分析出一般都是非理想配比的。体溶解速率与比表面积不存在简单的比例关系,但当单晶典型尺寸大于矿物表面上相临缺陷的间距时,体溶解速率则与比表面积呈正比。酸性条件下的溶解速率与H 活度正相关。源于可溶有机质的有机配位体能够络合溶液及固–液界面上的金属离子,可显著提高溶解速率。温度对溶解速率的影响受控于阿雷尼乌斯方程。鉴于硅酸盐矿物溶解规模的影响因素与滑坡灾害的发生条件基本一致,在滑坡灾害的区域性评价中,可以考虑纳入流域地表水化学组分浓度这一地球化学指标。植被可以提高斜坡岩土体的酸度、有机质丰度及地下水径流量,在促进硅酸盐矿物溶解及深层滑坡孕育方面的作用是显著的。     

基于水化学动力学方法的水文地质参数确定

利用天然地下水中各化学组分的迁移规律,从矿物化学组分运移方程入手,推导用化学动力学、化学热力学和地下水动力学表示的矿物吸附、溶解动力学方程,并用化学指标表示渗透系数、导水系数的解析表达式。基于研究区的水质资料,用水化学动力学方法能够求解含水层的水文地质参数,将该方法应用于抽水蓄能电站厂房区含水层参数的确定,并与压水试验法确定的参数进行对比,从而验证该方法的有效性,表明该方法具有广阔的应用前景。     

马来酸左旋氨氯地平分散片溶出度测定

建立马来酸左旋氨氯地平(玄宁)分散片溶出度的测定方法.以0.1 mo1/L盐酸溶液为溶出介质,采用浆法(50 r/min)20 min取样,运用紫外-可见分光光度法测定溶出度,检测波长为237 nm,并考察了溶出曲线,样品溶出均一性良好,溶出度均＞90%,该方法可用于马来酸左旋氨氯地平分散片的溶出度的测定.     

油页岩有机质的逐级热溶解聚及产物特性

依兰油页岩有机质经过四氢萘逐级热溶解聚,热溶解聚物分别经过GC-MS检测并归纳分类,并结合热溶解聚残渣的FT-IR和¹³C NMR分析结果,旨在从分子水平上揭示依兰油页岩有机分子结构特征。结果表明,依兰油页岩有机质经过200~400℃逐级热溶解聚后,200、300、350、375和400℃温度条件下逐级热溶解聚物的收率分别为8.8%、9.9%、18.5%、19.2%和23.4%,总收率达79.8%。在可溶性组分中,脂肪烃化合物占比为36.9%（其中直链烷烃27.4%,支链烷烃8.7%）,酚/醇类占比为5.5%,芳香烃占比为32.0%,酮类占比为12.7%,醚/酯类占比为5.4%,其他化合物占比为7.5%。呈现脂肪烃>芳烃化合物>酮类>酚/醇>酯/醚的规律分布状态,其中27.4%直链烷烃中碳数分布在14~30并在C₁₆和C₂₆呈现两个峰值。     

Insights into the Dissolution Kinetics of NaLAS Tablets

In this work, the dissolution behaviors of a series of sodium alkylbenzenesulfonates (NaLAS) tablets with different moisture contents and neutralization degrees were investigated in aqueous solution. The ANOVA‐based, model‐independent and model‐dependent methods were employed to perform comparison analyses on dissolution profiles. The measurements of powder X‐ray diffraction patterns and mechanical properties elucidate distinct differences in each formula. The results show that ANOVA provides a possibility for finding the source of differences among different variables, and the model‐independent methods including the k values and mean dissolution time are easy to interpret and perform comparison analyses. The Hixson–Crowell model gives satisfactory correlation results for the dissolution data and the dissolution kinetics parameters are obtained. The inhibition effects of neutralization degree and moisture content on NaLAS dissolution were examined, which reveals that the increase in lamellar phase proportion leads to the reduction of dissolution rate. The comparison analyses performed in this work form part of a methodology for dissolution profile prediction and comparison.     

Assessment of methods for studying the dissolution of phosphate fertilizers of differing solubility in soil

Relationships between plant response and rates of dissolution of ground (< 150µm) North Carolina phosphate rock (NCPR), NCPR 30% acidulated with phosphoric acid (NCPAPR) and monocalcium phosphate (MCP) were assessed in pot experiments. The three fertilizers were incubated for 1, 50 and 111 days, at the rates of 75, 150 and 750µg P g^–1 soil, using two soils with different P-retention capacity. After each period of incubation, four pots were set up from each treatment, and perennial ryegrass (Lolium perenne) was grown in a growth chamber for about six weeks to assess the agronomic effectiveness of the fertilizers. Results in dry matter yield and P uptake showed that immediately following application (1 day incubation), the MCP (solution) was supplying more P to plants than either the NCPR or the NCPAPR applied at the same rate. After 50 and 111 days of incubation, the NCPR and NCPAPR were just as effective in the lower P-retention Tekapo soil. The relative agronomic effectiveness (RAE) of the NCPR and NCPAPR compared with MCP was generally poorer in the higher P-retention Craigieburn soil than in the Tekapo soil shortly after application, but improved with time of incubation. Ryegrass responses to the application of the three fertilizers corresponded to the changing trends of exchangeable P in the soils, measured by the isotopic method.Regressions were made between plant P uptake and indices describing the intensity factor (water extractable P), quantity factor (Bray I P, Olsen P, 0.5M NaOH extractable P and isotopic exchangeable P) and the kinetic factor (F_in) of soil P supply to plants in the Tekapo soil. The percentage of variation in plant P uptake explained by individual indices was generally less than 80%, no matter which of the three single variable models, the Mitscherlich, the quadratic or the power function was fitted. However, more than 96% of the variation in plant P uptake in the Tekapo soil could be explained by the power function models involving two variables. The rate of P dissolution (F_in) determined by the isotopic dilution method was included in all the two variable models. The results suggest that assessment of soil P supply to plants should consider the kinetic factor in addition to the intensity and quantity factors, particularly where P fertilizers with differing solubility are applied.