Thermal dissolution of Estonian oil shale

The thermal dissolution of Estonian oil shale, kukersite and thermobitumen (TBO) formed, in the presence of solvents (benzene, ethanol, water and oil shale petrol) in autoclaves was studied. In all the solvents, except subcritical water, the total yield of benzene-soluble products, TBO, has a maximum (about 90%) at an optimum residence time and thereafter decreases due to coke formation. The formation of TBO from kukersite in supercritical water, ethanol and oil shale petrol is accelerated in comparison with low-temperature pyrolysis of kukersite without any solvent. The tests carried out with TBO without the mineral matter indicate deceleration of the coke formation in comparison with the initial kukersite.     

Parallels between slow pyrolysis of Estonian oil shale and forest biomass residues

Different types of forest residual biomass, including pine wood, pine bark and spruce needles, and Estonian Kukersite oil shale, were parallelly subjected to the slow pyrolysis in similar conditions. A Fischer assay, modeling industrial semi-coking retorts, was used. Both the yield and the composition of liquid, gaseous and solid products of pyrolysis were determined. FTIR-spectroscopic and chromatographic methods were used to study products group and individual composition. Common and specific features in biomass and oil shale semi-coking have been described. In comparison with oil shale, the biomass yielded less oil and more gas. Specifically large amounts of reaction water and carbon dioxide were obtained in biomass pyrolysis resulting in formation of significantly deoxygenated liquid and solid products. Bio-oils can be distinguished by the solubility in conventional solvents. Kukersite shale oil and the benzene-soluble fractions of different bio-oils were characterized by similar group composition.     

Comparative combustion study of some polymers with oil shale

In this study, the combustion kinetics of G?ynük oil shale, polyethylene, polyethylene glycol (PEG), polymethyl methacrylate (PMMA), polyvinyl chloride, and polymer?Coil shale blends were investigated by thermogravimetric analysis. Experiments were conducted at non-isothermal conditions with a heating rate of 5?K?min^?1 in the 298?C1173?K temperature interval under air atmosphere. An increase in the total conversion values with increasing mass percentage of polymers of the blends was observed. Differential thermogravimetric data were analyzed by an Arrhenius model. Effects of blending ratio of oil shale and polymer on the combustion kinetics were investigated. Kinetic parameters were determined and the results were discussed. An increase was observed in the frequency factor and activation energy values as the weight percentage of polymer in blends were increased. The minimum activation energy, 16.1?kJ?mol^?1, was calculated for PEG/oil shale with 2/3 blending ratio.     

Thermal behavior of Al-, AlFe- and AlCu-pillared interlayered clays

The purified bentonite parent clay, fraction ≤; 2 mm of montmorillonite type, has been pillared by various polyhydroxy cations, Al, AlFe and AlCu, using conventional pillaring methods. The thermal behavior of PILCs was investigated by combination of X-ray diffraction (XRD), thermal analysis (DTA, TG) and low temperature N2 adsorption/desorption (LTNA). Thermal stability of Al-, AlFe- and AlCu-PILC samples was estimated after isothermal pretreatment in static air on the temperatures 300, 500, 600 and 900°C. Crucial structural changes were not registered up to 600°C, but the fine changes in interlayer surrounding and porous/microporous structure being obvious at lower temperatures, depending on the nature of the second pillaring ion. AlFe-PILC showed higher thermal stability of the texture, the AlCu-PILC having lower values and lower thermal stability concerning both overall texture and micropore surface and volume. Poorer thermal stability of AlCu-PILC sample at higher temperatures was confirmed, the presence of Cu in the system contributing to complete destruction of aluminum silicate structure, by 'extracting' aluminum in stabile spinel form. This revised version was published online in July 2006 with corrections to the Cover Date.     

Thermal behavior and immersion heats of selected clays from Turkey

Four clays (two bentonites and two kaolinites) from Turkey were investigated by X-ray diffraction (XRD), thermal analysis (DTA/TG-DSC) and surface area measurement techniques. Mineralogically bentonite samples were characterized low concentration of montmorillonite and high level of impurities. Both kaolinite samples mainly contained kaolinite and quartz as major mineral. TG-DTA curves of all clay samples were measured in the temperature range 30–1200 °C. The total % weight losses for the bentonite samples (B1 and B2) and the kaolinite samples (K1 and K2) were determined as 14.50, 13.42, 5.55 and 11.85%, respectively. Differential Scanning Calorimeter (DSC) analyses of samples were carried out by heating the samples from 30 to 550 °C. The immersion heats of clay samples were measured using with a Calvet-type C-80 calorimeter. The higher exothermic Q_imm values were determined for bentonite samples compared to kaolinite samples.     

Thermal analysis studies of oil shale residual carbon

Thermal analysis has been used to determine the impact of heating on the decomposition reaction of two Moroccan oil shales between ambient temperature and 500°C. During pyrolysis of raw oil shale, the residual organic matter (residual carbon) obtained for both shales depends on the heating rate (5 to 40°C min^-1). Three stages characterize the overall process: the concentration of carbonaceous residue decreases with increase of heating rate, become stable around 12°C min^-1 and continue to decrease at higher heating rates. Activation energies were determined using the Coats-Redfern method. Results show a change in the reaction mechanism at around 350°C. Below this temperature, the activation energy was 41.3 kJ mol^-1 for the decomposition of Timahdit, and 40.5 kJ mol^-1 for Tarfaya shale. Above this temperature the respective values are 64.3 and 61.3 kJ mol^-1. The reactivity of Timahdit and Tarfaya oil shale residual carbon prepared at 12°C min^-1 was subject to a dynamic air atmosphere to determine their thermal behaviour. Residual carbon obtained from Tarfaya oil shale is shown to be more reactive than that obtained from Timahdit oil shale. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of acid treatments on Moroccan Tarfaya oil shale and pyrolysis of oil shale and their kerogen

In this study, the kerogen of oil shale from Moroccan Tarfaya deposits was isolated and the changes in the initial organic matter during the removal of the mineral matrix were examined. Chloroform extraction of the oil shale increases the intensity of the peaks in the X-ray diffractograms. Infrared spectra and X-ray diffractograms reveal the presence of mineral, calcite, quartz, kaolinite, and pyrite in the mineral matrix of the oil shale. Hydrochloric and hydrofluoric acids dissolution do not alter the organic matter. The nonisothermal weight loss measurements indicate that thermal decomposition of the isolated kerogen can be described by firstorder reaction. A single kinetic expression is valid over the temperature range of kerogen pyrolysis between 433K and 873K. Furthermore, the results indicate that the removal of mineral matter causes a decrease in the activation energies of the pyrolysis reactions of oil shale.     

Thermal behavior of some antihistamines

Thermogravimetry (TG), differential scanning calorimetry (DSC), polarized light thermal microscopy (PLTM), as well as X-ray powder diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR) were used to study the thermal behavior and the chemical structure of cimetidine, famotidine, ranitidine-HCl, and nizatidine. The TG–DSC curves show that the famotidine and ranitidine-HCl suffer decomposition during melting and they are thermally less stable in comparison with cimetidine and nizatidine, the latter being the most stable of all the drugs studied in this study. The DSC curves of famotidine and ranitidine-HCl show exothermic peaks immediately after the melting, confirming the occurrence of thermal decomposition. The DSC curves also show that the cimetidine and nizatidine have some thermal stability after melting. The thermal events shown in the PLTM images are consistent with the results shown in the TG–DSC and DSC curves. The XRD patterns show that the cimetidine and famotidine are less crystalline compared with ranitidine-HCl and nizatidine. The theoretical FTIR bands are in agreement with those obtained experimentally, and in some cases, no difference is observed between the theoretical and experimental values, even being identical in one of the cases.     

Influence of the post-granulation treatment on the thermal behaviour and leachability characteristics of Estonian oil shale ashes

The power and heat production in Estonia is based over 90% on the combustion of a local solid fossil fuel—Estonian oil shale (OS), and at that 7–8 million tons of OS ash are formed annually. One promising possibility for large-scale utilization of cheap alkali ashes is the liming of acidic soils. In Estonia, there is 350,000 ha of agricultural land that needs permanent liming. To eliminate possible environmental contamination at liming of soils the oil shale ashes should be granulated. Thermal analysis was used for determination of the relationships between physico-mechanical and physico-chemical characteristics of granulated products and the post-granulation treatment conditions. For determination of leachability of ash components, the granulated products as well as the origin ashes were tested using laboratory lysimetries. Depending on OS ash and different post-granulation treatment used, it was possible to obtain granulated product with compressive strength between 5 and 15 N per granule. The leaching of Ca²⁺ decreased up to 26 and 34%, SO₄ ^2? 70 and 53%, Mg²⁺ and K⁺ up to 7–12% for granulated CA and ESPA, respectively, comparing with original ashes. The results of soil analysis indicate that the use of OS ashes improved the pH level of soil significantly. pH increased equally with initial and granulated ash: from 4.7 up to 6.4 and 5.8, respectively, using for that CA and ESPA. Prolonged effect of soil neutralizing ability by granulated product (if compare with fine ashes) was proven by decrease in the content of leached ions in filtrate solutions as well as not mobile ions in soil.     

油页岩热解过程矿物质行为分析

采用XRD、SEM、灰成分测定等方法对桦甸两个矿区的油页岩样品以及制备的半焦样品矿物质组成进行了分析,确认其主要成分均为,石英、方解石和黏土矿物。而半焦中矿物组成反映了油页岩中矿物质在热解中的变化。研究表明,在热解过程中油页岩中矿物质变化细微,其中,石英、长石没有变化;方解石有微量分解,生成的固体产物CaO与黄铁矿分解的硫反应生成CaS矿物;黏土矿物质受热脱除羟基,放出大量水分,同时分解产生的无定形玻璃体氧化硅与其他金属形成低熔点的共融物,导致部分半焦样品颗粒表面出现熔融态囊状结构。     

Thermal behavior of ammonium dinitramide and amine nitrate mixtures

Journal of Thermal Analysis and Calorimetry - This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate...     

Thermal behavior of some cholesteric esters

Taking into account the importance of thermal stability in the liquid crystals field, the study presents thermal behavior of some cholesteric esters, which differ by the nature of the functional group attached to the cholesteryl unit and the connecting position of the nitro or amino functions to the aromatic ring. The cholesteric esters present liquid crystalline properties, with high melting and clearing points and may be used as intermediates in the synthesis of liquid crystals. Some other kinetic characteristics, such as reaction order (n), activation energy (E_a) and pre-exponential factor (lnA) have been also evaluated. The type of functional units adjacent to the aromatic unit determines thermal stability of the cholesteryl compounds. Groups with a powerful withdrawing effect induce a decreasing of the temperatures at which the material starts to lose mass. An increased thermal stability for the amino esters has been observed, probably because of some intermolecular hydrogen bonds formation.     

油页岩飞灰对重金属离子的吸附动力学及热力学

采用批式振荡吸附法研究了燃油页岩电厂循环流化床锅炉飞灰对重金属离子Pb²+、Cu²+、Zn²+、Cd²+的吸附动力学及吸附热力学特性,并提出了吸附机理。结果表明,油页岩飞灰对Pb²+、Cu²+、Zn²+、Cd²+的吸附平衡数据符合Langmuir和Freundlich吸附等温方程,但Freundlich方程能够更好地描述吸附等温线。在油页岩飞灰对重金属离子吸附的初始阶段,拉格朗日准一级动力学方程、准二级动力学方程、Elovich方程、粒子内扩散模型均能很好地反映吸附模式,而整个吸附过程则遵循二级反应动力学方程,其吸附过程是液膜扩散和粒子内扩散共同作用的结果。油页岩飞灰对Pb²+、Cu²+、Zn²+、Cd²+的吸附是吸热反应。     

Thermal behavior and decomposition kinetics of ETN and its mixtures with PETN and RDX

Erythritol tetranitrate (butane-1,2,3,4-tetrayl tetranitrate, ETN) has become one of the most synthesized improvised explosives nowadays as it can be found on public internet discussion boards. However, the low melting point, nitrocellulose gelling ability, high energy content, and availability of its precursor make the substance potentially useful in industry as an energetic component or additive in certain gun propellants. Mixtures of ETN with other high explosives are also frequently discussed on web pages dealing with improvised explosives. This article describes thermal behavior and decomposition kinetics of pure ETN and its mixtures with pentaerythritol tetranitrate and cyclonite (1,3,5-trinitro-1,3,5-triazinane, RDX). The thermal behavior and decomposition kinetics of such mixtures are described using non-isothermal DSC and TG techniques. Kissinger method, Soviet manometric method, and modified Kissinger–Akahira–Sunose method were used for data evaluation.     

Thermal diffusivity of green river oil shale by the laser-flash technique

The thermal diffusivity of Green River oil shale has been measured by the laser-flash technique. Measurements were carried out in the temperature range 25–350°C and for various grades of shales ranging from 6 to 100 gal./ton. The thermal diffusivity (α) is seen to decrease with increasing temperature, especially for shales with low organic content. Richer shales, on the other hand, show very little sensitivity in their α values to temperature and grade. The α values measured for Green River oil shales fall in the range 0.1–0.9×10^?2 cm²/sec. Anisotropic effects were also observed for these α values; shales cored parallel to their bedding planes the diffusivities about 20–30% higher than those for the samples cored perpendicular to the stratigraphic planes. The presence of pore water in the shale is also shown to have a significant effect on α.     

Polymers,additives, surfactants and their mixtures: Computer-based search with special ftir libraries

This investigation was done with a PC of 850 MB/33 MHz, Windows 3.1 and the SPECTACLE program of LabControl/Cologne. The libraries contained standardized FTIR spectra of 3061 defined polymers, 530 industrial polymers and resins, 1969 additives (pigments, stabilizers, plasticizers etc.) 1190 surfactants and 1614 monomers, pyrolyzates and educts. For searches, the data density was reduced to 4/cm. Similarity search with standardized full spectra yields quantitative dissimilarity figures; it allows an experimental definition of identity. The derivative functions 3 and 4 of Lowry and Huppler increase the gap between identical and similar spectra. With the LH2 algorithm spectra are defined as identical if their dissimilarity values are within 10³. Since all organic matter has some spectral similarity the LH2 dissimilarity for organics will not go far beyond 10⁵. - The quality of IR preparation has a strong impact on search results. If a library contains spectra with false-light, Christiansen effect, high noise or other artefacts, peak search yields better results than similarity search with full spectra. Multicomponent systems can be searched successfully for their constituents with an algorithm combining peak and similarity searches. This algorithm is superior to all other algorithms if a library contains spectra with artefacts.