El-Lajjun Oil Shale Research Articles

PYROLYSIS OF ELLAJJUN OIL SHALE UNDER THE INFLUENCES OF NITROGEN AND WATER VAPOR

The pyrolysis of Ellajjun (Jordan) oil shale was carried out in a fixed bed retort in temperature range of 360 – 550oC using either nitrogen or nitrogen-steam mixture as sweeping gas. Differences were observed between the total weight loss and product compositions. Pyrolysis under nitrogen-steam mixture gave larger increase in weight loss as pyrolysis temperature increased. The retorted shale oil samples under the influence of either nitrogen or nitrogen-steam were distilled. The gasoline- naphtha and kerosene fractions from simple atmospheric distillation, were increased by 35% and 65% (vol.) respectively while, diesel fraction was decreased by 45% vol. compared with nitrogen pyrolysis.

Sulfur distribution in the oil fractions obtained by thermal cracking of Jordanian El-Lajjun oil Shale

The extracted shale oil by the thermal cracking process of the El-Lujjan oil shale showed that the yield of oil was around 12 wt%. The amount of sulfur in this shale oil was found to increase (from 7 to 9.5 wt%) with the increase of the boiling point for different distillate fractions. Sulfur in Jordanian oil shale was found to be mainly organic sulfur with negligible amounts of inorganic sulfur. Sulfur was found to be in the aromatic form in these fractions. Different forms of thiophenes were found in all fractions of the shale oil extracts without a distinct change in the concentration of any specific compounds with these extracts. Alkylthiophenes were the dominant phases in these fractions.

Thermal Conductivity of Oil Shale Particles in a Packed Bed

A steady-state one-dimensional heat transfer method was used to measure the effective thermal conductivity of Sultani and El-Lajjun oil shale particles. The particles were packed in a cylindrical bed and heated uniformly over a temperature range of 25 to 250°C. The effect of particle sizes of < 250, 500-710, and 1000-1400 w m on thermal conductivity was also investigated. The effective thermal conductivity of the samples was observed to decrease with increasing temperature. Moreover, the values of thermal conductivity were found to increase with increasing oil content of the shale samples. Over the tested range, particle size showed little effect on thermal conductivity.

A comparison of retorting and supercritical extraction techniques on El-Lajjun oil shale

A comparison of retorting and supercritical extraction techniques on El-Lajjun oil shale

A Comparison of Retorting and Supercritical Extraction Techniques on El-Lajjun Oil Shale

In this study, the use of nitrogen retorting, carbon dioxide retorting, supercritical CO2 extraction, and supercritical H2O are compared for oil yield, quality, and the types and amounts of compounds eluted from Jordanian El-Lajjun oil shale. Results show that supercritical H2O (SC-H2O) produces 50% higher yields than nitrogen retorting (R-N2) while releasing higher molecular weight materials through solvation and pyrolysis. The use of supercritical CO2 (SC-CO2) provides the greatest production of mid-distillate compounds while producing the lowest overall yield due to the lack of pyrolysis. Retorting using CO2 (R-CO2) provides a narrower molecular-weight distribution than N2 while improving the oil yield slightly. It is also established that shale oil can be extracted by supercritical fluid extraction that is operated at substantially lower temperatures, where solvation dominates pyrolysis as a predominant mechanistic step. The potential of El-Lajjun oil shale as a valuable energy source has also been analyzed.

Retorting of Oil Shale Followed by Solvent Extraction of Spent Shale: Experiment and Kinetic Analysis

Samples of El-Lajjun oil shale were thermally decomposed in a laboratory retort system under a slow heating rate (0.07 K/s) up to a maximum temperature of 698-773 K. After decomposition, 0.02 kg of spent shale was extracted by chloroform in a Soxhlet extraction unit for 2 h to investigate the ultimate amount of shale oil that could be produced. The retorting results indicate an increase in the oil yields from 3.24% to 9.77% of oil shale feed with retorting temperature, while the extraction results show a decrease in oil yields from 8.10% to 3.32% of spent shale. The analysis of the data according to the global first-order model for isothermal and nonisothermal conditions shows kinetic parameters close to those reported in literature.

96/04900 Comparison between continuous stirred tank reactor extractor and Soxhlet extractor for extraction of El-Lajjun oil shale

A new method is proposed to evaluate kinetic parameters and mass transfer coefficients for adsorption processes carried out in continuous stirred tank reactors. This method, employing a biphasic model, does not linearize nonlinear solute concentration versus time data, nor does it assume the existence of equilibrium in a typical nonequilibrium situation as is currently done. For a nonlinear adsorption isotherm, the coupled differential equations need to be solved numerically, but using an elegant analytical solution it is possible to determine rate constants and mass transfer coefficients in the case of nonlinear kinetics with a linear adsorption isotherm. This solution (biphasic model, linear isotherm) is obtained and compared with solutions incorporating (i) a linear model (linear isotherm) and (ii) a numerical solution (nonlinear isotherm) for recovery of the antibiotic novobiocin in stirred tank reactors. For novobiocin adsorption versus time data, use of the biphasic model results in a lower mean percentage error than either the linear model or the numerical simulation; further, it provides a far superior fit of short-time adsorption behavior. Hence, we strongly advocate that the biphasic model be routinely employed along with linear models and numerical simulations of Langmuir/Freundlich isotherms for interpretation of adsorption data.

96/01472 Extraction of El-Lajjun oil shale

96/01472 Extraction of El-Lajjun oil shale

Comparison between Continuous Stirred Tank Reactor Extractor and Soxhlet Extractor for Extraction of El-Lajjun Oil Shale

Abstract Extraction of El-Lajjun oil shale in a continuous stirred tank reactor extractor (CSTRE) and a Soxhlet extractor was carried out using toluene and chloroform as solvents. Solvents were recovered using two distillation stages, a simple distillation followed by a fractional distillation. Gas chromotography was used to test for the existance of trapped solvent in the yield. It was found that extraction using a CSTRE gave a 12% increase in yield on average compared with the Soxhlet extractor, and an optimum shale size of 1.0 mm offered a better yield and solvent recovery for both techniques. It was also found that an optimum ratio of solvent to oil shale of 2:1 gave the best oil yield. The Soxhlet extractor was found to offer an extraction rate of 1 hour to complete extraction compared with 4 hours in a CSTRE. The yield in a CSTRE was found to increase an increase of stirring. When extraction was carried out at the boiling point of the solvents in a CSTRE, the yield was found to increase by 30% on average compared to that of extraction when the solvent was at room temperature. When toluene was used for extraction, the average amount of bitumen extracted was 0.032 g/g of oil shale and 85.8% of the solvent recovered, compared with 0.0293 g/g of oil shale and 89.9% of the solvent recovered using a Soxhlet extractor. When chloroform was used for extraction, the average amount of bitumen extracted was 0.039 g/g of oil shale and 76.4% of the solvent recovered, compared with 0.037 g/g of oil shale and 84.1% of the solvent recovered using a Soxhlet extractor.

Extraction of El-Lajjun Oil Shale

Abstract Extraction of the bitumen fraction of El-Lajjun oil shale was carried out using 17 different solvents, pure and combined. Out of all the solvents used, toluene and chloroform were found to be the most efficient for extraction of the bitumen to perform the major part of the experiments. This selectivity was based on the quality and quantity of the yield and on the quantity of solvent recovered. Extraction was carried out using a Soxhlet extractor. For complete recovery of solvent the extract phase was subjected to two stages of distillation, simple distillation followed by fractional distillation, where different cuts of oil were obtained. It was found that an optimum shale size of 1.0 mm offered better solvent recovery. One hour was the optimum time needed for complete extraction. The yield of oil was determined from the material balance gained from fractional distillation after testing for the existence of any traces of solvent trapped in the different cuts by using a gas chromotography techniqu...

Effect of Composition of El-lajjun Oil Shale on Its Calorific Value

Abstract A geochemical analysis of El-lajjun oil shale in Jordan was carried out. It was found that El-lajjun oil shale consists of the following groups: organic matter, biogenic calcite and apatite, detrital clay minerals, and quartz. The calorific values of 100 samples of shale were determined. The effect of bore depth, calcium carbonate, organic carbon, and sulfur content on the calorific values were studied. Results were well correlated by the following equation Calorificvalue=352,44(CaCO3)-0.066(S)0.257(Corg)1.141 with correlation coefficient of 0.983 and with an average standard error of 2.63%.

Potential uses of Jordanian spent oil shale ash as a cementive material

Retort residue ash of El-Lajjun oil shale from central Jordan has been studied for its cementitious and pozzolanic properties and potential uses in construction. During the preliminary phase, properties of the ash were determined and some tests were performed on pastes of ash, cement and their mixtures. According to X-ray diffraction and thermogravimetric studies, the ash mainly consisted of calcite and silica and some lime silicates, providing cementitious character. Its hydration resulted in ettringite and lime silicate gel formation. The ash paste had relatively low setting times and hardened into a lightweight porous structure. Its 28 day strength was about half of the cement paste value for the same water content. The ash had weak pozzolanic activity. In blended pastes, addition of ash up to 30% caused some reductions in 28 day strengths. There seemed to be optimum ash contents which improved compactibility while causing minimum strength reductions. The results indicated that the ash could be used to produce lightweight masonry and building units having medium strengths. It showed potential for use as an admixture in cement and concrete.