Goynuk Oil Shale Research Articles

FAST PYROLYSIS AND CO-PYROLYSIS OF GÖYNÜK OIL SHALE (TURKEY) AND POLYPROPYLENE IN FREE FALLING REACTOR (FFR)

Fast pyrolysis of Goynuk oil shale (GOS), polypropylene (PP) and the blend of GOS:PP on a 1:3 total carbon ratio basis was studied. The maximum product evolution temperature and the existence of synergistic effect were determined and the characteristics of pyrolysis products by carbon number were investigated. Pyrolysis products were analyzed by capillary gas chromatography. The volatile fraction of pyrolysis products was classified according to carbon number. Conversion to the volatile fraction of recovered hydrocarbons in fast copyrolysis of GOS:PP increased with increasing temperature. The effect of PP on the conversion of GOS was determined by calculating the difference between experimental and hypothetical mean values of conversion of total organic carbon into volatile products and a slight synergistic effect was observed at 600 C (4.78%) and 650 C (5.07%).

Comparative combustion study of some polymers with oil shale

In this study, the combustion kinetics of Goynuk oil shale, polyethylene, polyethylene glycol (PEG), polymethyl methacrylate (PMMA), polyvinyl chloride, and polymer–oil 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 298–1173 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.

LOW-TEMPERATURE PYROLYSIS AND CO-PYROLYSIS OF GÖYNÜK OIL SHALE AND TEREBINTH BERRIES (TURKEY) IN AN AUTOCLAVE

Low-temperature pyrolysis of Turkish Goynuk oil shale (GOS) and terebinth berries as individual objects and their dry and hydrous co-pyrolysis in a closed system, in an autoclave was studied. The effect of pyrolysis conditions (temperature and duration) on the yield of extracts (hexane and benzene), gas and organic residue was investigated. The composition of extracts was determined via thin layer chromatography. The yield of the extracts increased with the increase of pyrolysis temperature and duration, and its maximum attained 48.5% from the initial organic matter for GOS and 40% for berries. On the other hand, supercritical water also affected product yields and composition of extracts derived from both GOS and terebinth berries. The total yields of extracts from hydrous pyrolysis were 57.3% and 60.0% for GOS and berries, respectively. However, the extracts of hydrous pyrolysis contained more polar heterocompounds and less nonaromatic hydrocarbons than those of dry pyrolysis. Addition of berries to GOS lowered the co-pyrolysis temperature about 10 °C for reaching the maximum yield of the total extract. Dry co-pyrolysis of GOS with berries resulted in additive rather than in synergistic effect in the total extract yield, but the composition of the extract as a fuel – more nonaromatic hydrocarbons (33.8%) and less heterocompounds (43.0%) than that of extracts from individual feedstocks – was improved. Similarly, in the case of hydrous co-pyrolysis, the yields of extracts (hexane and benzene), gas and organic residue consisted of partial contributions of the yields from the initial feedstocks.

Kinetics of combustion of oil shale with polystyrene

The combustion kinetics of Goynuk oil shale, polystyrene and several polystyrene-oil shale blends were investigated by thermogravimetric analysis in the present study. Experiments were conducted at non-isothermal conditions with a heating rate of 5, 10 and 20 K min−1 in the 298–1173 K temperature interval under an air atmosphere. Differential thermogravimetric data were analyzed by two different models. Effects of blending ratio of oil shale and polystyrene and heating rate on the combustion kinetics were investigated. Kinetic parameters were determined and the results were discussed.

EFFECT OF MINERAL MATTER ON PRODUCT YIELD AND COMPOSITION AT ISOTHERMAL PYROLYSIS OF TURKISH OIL SHALES

This study was aimed to investigate the effect of mineral matter of Goynuk oil shales (GOS) on pyrolysis and product evolution. Organic part was separated from mineral matter before pyrolysis in an isothermal pyrolysis reactor. In the demineralization step, carbonate, pyrite and silicates were removed from kerogen by using HCl, HNO 3 and HF, respectively. Thereafter all samples were pyrolized in an isothermal pyrolysis apparatus. The temperatures for pyrolysis experiments were 450, 500, 550, 600, 650 °C. Recoveries of volatiles and total hydrocarbons increased with increasing temperature. At pyrolysis of silicate-free oil shale (GOS-F), volatile hydrocarbon recovery (VHR) increased nearly by 10 wt.% as compared with VHR from raw oil shale sample (GOS-R) at each pyrolysis temperature. Carbon content of solid residue was also calculated. The effect of mineral content of oil shale on product yield and composition was determined by establishing carbon balance in the reactor. The amount of solid residue decreased as a function of demineralization degree. The pyrolysis reaction in the presence of silicate mineral showed the catalytic effect of silicate minerals aiding coking reactions, and carbon deposition decreased averagely by 20 wt.% in silicatefree oil shale compared with the value for GOS-R at each temperature.

Classification of volatile products evolved at fast co-pyrolysis of Goynuk oil shale with low density polyethylene

Fast co-pyrolysis of Goynuk oil shale (GOS) with low density polyethylene (LDPE) was investigated. The aim of the research was to determine the distribution of volatile products and conversion of blends at different temperatures and time intervals. Pyrolysis of oil shale, LDPE and co-pyrolysis of oil shale-LDPE blend of the total carbon ratio of 1:1 were performed by using the fast pyrolysis method in an isothermal pyrolysis reactor. Volatile organic products eluted from the reactor were collected at different temperatures and time intervals by using a special sampling technique. Fast pyrolysis products were analyzed by capillary gas chromatography. In the aliphatic fraction of pyrolysis products, n-paraffins and 1-olefins were classified by their carbon number. The effect of co-pyrolysis on conversion of total organic carbon into volatile products was identified by determination of the experimental and the hypothetical mean values. Possible synergetic effect was investigated by comparing the results on fast pyrolysis of GOS and LDPE. The effect of co-processing of GOS with LDPE was determined by calculating the difference between experimental and hypothetical mean value of conversion of total organic carbon into volatile products. The experimental conversion of the blend to volatile hydrocarbons was found to be lower than hypothetical mean value of conversion at co-pyrolysis, and thus, no synergetic effect was observed.

CLASSIFICATION OF VOLATILE PRODUCTS EVOLVED AT FAST CO-PYROLYSIS OF GÖYNÜK OIL SHALE WITH LOW DENSITY POLYETHYLENE

Fast co-pyrolysis of Goynuk oil shale (GOS) with low density polyethylene (LDPE) was investigated. The aim of the research was to determine the distribution of volatile products and conversion of blends at different temperatures and time intervals. Pyrolysis of oil shale, LDPE and co-pyrolysis of oil shale-LDPE blend of the total carbon ratio of 1:1 were performed by using the fast pyrolysis method in an isothermal pyrolysis reactor. Volatile organic products eluted from the reactor were collected at different temperatures and time intervals by using a special sampling technique. Fast pyrolysis products were analyzed by capillary gas chromatography. In the aliphatic fraction of pyrolysis products, n-paraffins and 1-olefins were classified by their carbon number. The effect of co-pyrolysis on conversion of total organic carbon into volatile products was identified by determination of the experimental and the hypothetical mean values. Possible synergetic effect was investigated by comparing the results on fast pyrolysis of GOS and LDPE. The effect of co-processing of GOS with LDPE was determined by calculating the difference between experimental and hypothetical mean value of conversion of total organic carbon into volatile products. The experimental conversion of the blend to volatile hydrocarbons was found to be lower than hypothetical mean value of conversion at co-pyrolysis, and thus, no synergetic effect was observed.

Thermal degradation kinetics of Göynük oil shale with polystyrene

Goynuk oil shale, polystyrene and several polystyrene-oil shale blends were degraded in a thermobalance apparatus at atmospheric pressure. Experiments were carried out dynamically by increasing the temperature from 298 to 1173 K with heating rates of 10 and 60 K min -1 under an argon atmosphere. Derivative thermogravimetric data were analyzed by a reaction rate model assuming first order kinetics. Effects of blending ratio of oil shale and polystyrene and heating rate on the thermal degradation kinetics were investigated. Kinetic parameters were determined and the results were discussed.

Sub- and Supercritical Water Extraction of G\"oyn\"uk Oil Shale

Goynuk oil shale was extracted with water at sub- and supercritical conditions. The pressure was varied from 0.1 to 32 MPa. The highest extraction temperature was 419°C. Under these conditions, the conversion degree, extract, and gas yields increase with temperature since the thermal cracking of the crosslinked polymerized coal structure leads to the formation of extractable products. Above the critical temperature of water, the conversion degree and extract yield decreased as a result of repolymerization of extracted products. Spent shale amount decreased with increasing temperature. The obtained extracts at different temperatures were separated into subfractions. It was attempted to explain the effect of experimental conditions on yields and the amount of subfractions as well.

Comparison of Retorting and Supercritical Extraction Techniques on Gaining Liquid Products from Goynuk Oil Shale (Turkey)

In this study, conversion of Goynuk oil shale to liquid products was investigated. In the first part of the study, pyrolysis of organic compounds called kerogen, which is the majority of organic material in oil shale, was performed and amounts of residue char, tar, water and gas were determined. After that, oil shale samples were extracted by toluene in an Autoclave and an amount of liquid products obtained by extraction and by pyrolysis was compared with each other. In addition asphaltene, oil, residue char and gas yields in the tar and the optimum conditions at which the maximum yields are obtained were determined. In the pyrolysis experiments, the effects of temperature on residue char, tar, gas and water were investigated. In conclusion, supercritical extraction is a more available method than pyrolysis in conversion of Goynuk oil shale to liquid products.

04/00626 Changes in the cross-link density of Goynuk oil shale (Turkey) on pyrolysis: Ballice, L. and Larsen, J. W. Fuel, 2003, 82, (11), 1305–1310

04/00626 Changes in the cross-link density of Goynuk oil shale (Turkey) on pyrolysis: Ballice, L. and Larsen, J. W. Fuel, 2003, 82, (11), 1305–1310

Changes in the cross-link density of Goynuk oil shale (Turkey) on pyrolysis ☆

The effect of temperature and heating rate on the cross-link density of char samples obtained by pyrolysing Goynuk oil shale was investigated using the volumetric solvent swelling technique. The cross-link density decreases slightly with increasing pyrolysis temperature. The heating rate and thus the pyrolysis time had at most a small effect on the cross-link density. Char–solvent interactions do not follow regular solution theory. The demineralized kerogen swells more than does the native kerogen (16% ash).

A Kinetic Approach to the Temperature-Programmed Pyrolysis of Turkish Oil Shales in a Fixed Bed Reactor: Determination of Kinetic Parameters for n-Paraffins and 1-Olefins Evolution

The thermal degradation of both Goynuk oil shales (GOS) and Beypazari oil shales (BOS) has been investigated under nonisothermal conditions. The recovery of organic carbon as 1-olefins and n-paraffins was determined by temperature-programmed pyrolysis of oil shales. A fixed bed reactor under argon flow was used to pyrolyze small samples of oil shales. A special gas-phase sampling technique was used to determine the composition of products eluted from the reactor as a function of temperature and time. Hydrocarbon evolution data have been analyzed by Coats-Redfern and Chen-Nuttall combinations. It must be emphasized that the evaluation of temperature-programmed pyrolysis data by combined use of Coats-Redfern and Chen-Nuttall methods provide satisfactory mathematical approaches to obtain kinetic parameters for 1-olefins and n-paraffins formation from thermal degradation of Turkish oil shales. Using this method, it is possible to identify every stage of pyrolysis and derive values for kinetic parameters.

00/01775 The effect of pyrite catalyst on the hydroliquefaction of Goynuk (Turkey) oil shale in the presence of toluene

00/01775 The effect of pyrite catalyst on the hydroliquefaction of Goynuk (Turkey) oil shale in the presence of toluene

A Novel Hydropyrolysis Approach for Optimum Release of Covalently-Bound Biomarker Hydrocarbon Skeletons from Sedimentary Organic Matter

In order to generate more representative biomarker profiles, geomacromolecules must first be fragmented into smaller (readily-analysable) structural units to gain access to the covalently-bound pool of biomarkers. Existing chemical degradation and pyrolysis methods for fragmenting and analysing molecular components of kerogen are notoriously poor at providing quantitatively significant and/or accurate data. Chemical degradation methods have been less successfully and less widely applied to kerogen in comparison with solvent-soluble macromolecular fractions (usually applied to polar fractions). In general, since the polar fractions represent only a small proportion of the total OM and the yields of routinely analysable products obtained from chemolysis are low, it follows that the biomarker profiles produced from chemical degradation may also be highly biased with respect to the total biomarker assemblage. With analytical pyrolysis methods, e.g. Py-GC-MS, higher conversions of kerogen can be achieved but the structural information about the molecular constituents that is provided (and hence the accuracy of biogeochemical information that is conveyed) is compromised to a significant extent due to the appreciable secondary reactions (cracking and isomerisation) of released products which manifest at the high pyrolysis temperatures employed (typically >600~ In order to generate more representative biomarker profiles, a far higher proportion of the biomarker constituents must be accessed. Reaction conditions are sought which solubilise a significant proportion of sedimentary OM (approaching 100% conversion), whilst maxiraising the level of structural (biogeochemical) information and minimising the extent of secondary reactions between degradation products. Pyrolysis at high hydrogen pressures (> 10 MPa, hydropyrolysis) eliminates the problem of low yields often associated with the use of sterically-bulky chemical reagents and limits the extent of retrogressive chemistry (leading to char-formation and rearrangement of detectable products) encountered in other analytical pyrolysis methods (e.g. flash-pyrolysis). Fixed-bed hydroyrolysis in the presence of a dispersed sulphided molybdenum catalyst gives rise to overall carbon conversions greater than 85% for petroleum source rocks (Type I and Type II ancient SOM) and high volatile coals (Type III OM), with high selectivities to dichloromethane-soluble tar and low hydrocarbon yields (Roberts et al., 1995). Previous work has demonstrated the unique ability of fixed-bed catalytic hydropyrolysis to release much higher yields of aliphatic biomarker hydrocarbons (including n-hydrocarbons, hopanes, steranes and methyl steranes) from immature kerogens in comparison with solvent extraction, mild catalytic hydrogenation and normal pyrolysis methods (Love et al., 1995, 1996). A combination of slow heating rate (5~ rain1), high hydrogen pressure (15 MPa) and use of a dispersed sulphided molybdenum catalyst represents the best regime for achieving high conversions to dichloromethane-soluble products whilst minimising the structural rearrangement of biomarker species (Love et al., 1997). Staged hydropyrolysis on Goynuk oil shale (NW Turkey, Oligocene, Type I) has confirmed that hopanes released at higher temperatures (above 350~ through cleaving relatively strong bonds (possibly by up to 4 or more ether linkages protected by a macromolecular matrix) are quantitatively more significant than those released at lower temperatures for this immature source rock with a relatively low organic sulphur content (Love et al., 1997). This important pool of (strongly-)bound biomarkers is especially difficult to isolate by existing chemical and thermal degradation methods. The very high yields of products, in combination with the retention of structural information that is observed, dictates that hydropyrolysis will generate a more sensitive and accurate biomarker profile for sedimentary OM than these existing approaches.

Nitrogen Fate during Laboratory Maturation of a Type I Kerogen (Oligocene, Turkey) and Related Algaenan: Nitrogen Mass Balances and Timing of N2 Production versus Other Gases

Parallel pyrolytic studies were carried out on an immature, ultralaminae-rich, type I kerogen (Goynuk oil shale kerogen) and a related algaenan (isolated from the extant green microalga Scenedesmus...

Speciation of the Organic Sulfur Forms in a Recent Sediment and Type I and II-S Kerogens by High-Pressure Temperature-Programmed Reduction

Temperature-programmed reduction (TPR) with a well-swept fixed-bed reactor operating at 15 MPa of hydrogen pressure has facilitated the speciation of the organic sulfur forms in coals and petroleum source rocks through complete hydrodesulfurization with typically 75-80% of the sulfur being released as hydrogen sulfide with the remaining 20-25% occurring as primarily thiophenic compounds in the oils obtained in high yield. In this study, the technique has been applied to kerogens isolated from a series of unconsolidated Peru margin sediments, and for comparison, to type I and II-S kerogens (Goynuk oil shale and Monterey Fm, respectively) from immature organic-rich rocks. Visual resolution in the hydrogen sulfide TPR evolution profiles has been achieved between mono- and di/polysulfidic forms with the latter being reduced below 250 °C. Indeed, di/polysulfides account for high proportions of the reduced sulfur in surficial sediment samples collected from close to the top of the sediment. In contrast, monosulfides are the dominant sulfur form in the sample analyzed from deeper in the Peru margin sediment where thiophenes account for up to ca. 35% of the organic sulfur. This distribution is remarkably similar to those found for both the type I and II-S kerogens investigated, indicating that the major changes in organic sulfur forms occur during the early stages of diagenesis.

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.

ORGANIC GEOCHEMISTRY OF THE GÖYNÜK AND SEYITOMER OIL SHALES OF TURKEY

The Goynuk and Seyitomer oil shales overlie coal seams. An investigation of their geochemistry by solid-state and high-resolution nuclear magnetic resonance, infra-red spectroscopy and gas chromatography/mass spectrometry of the extracted bitumen suggests a classification as immature Type I kerogens. However, the n-alkane distribution is consistent with a substantial input from terrestrial plants.