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Hydrocarbon Production from Oil Shales (Himmetoğlu-Hatıldağ)
Hüseyin Çalışgan, Erşan Alpay, Y. Haluk İztan
Turkish Petroleum Corporation, Research Center, Ankara
The known producible oil and gas reserves are assumed to be diminishing or declining in near future.
Deposits of oil shale are in many parts of the world. The alternative to oil and gas energy resources should
be investigated. The oil shale sources especially in Western Anatolia Region should be focused to search
its energy potential and oil productivity feasibilities technically, economically and commercially. Energy
development is getting more important each day, especially for developing countries like Turkey. In order
to decrease the dependency on energy exporting countries, alternative fossil fuel resources of Turkey
need to be further investigated. Oil shale resources are the second largest fossil fuel resources of Turkey
especially in Beypazarı – Bolu Mudurnu Göynük Himmetoğlu and Hatıldağ field. The most effective way of
processing oil shales is the retort technique which is converting kerogen into synthetic crude oil by pyrolysis,
hydrogenation, or thermal dissolution. The retort technique can be applied as surface or in situ retorting.
For the mineable part of an oil shale resource, surface retorting is the most appropriate method. It is mostly
a continuous process in which the raw oil shale undergoes pyrolysis under the effect of heat, yielding oil and
waste products. Since it is a continuous process, it demands applying heat for an extended time, requiring
a significant amount of energy. To minimize the energy consumption in retort technique, electromagnetic
heating can be employed as an alternative recovery method. Oil shale is a general expression usually
used for a finegrained sedimentary rock, containing significant amounts of kerogen, from which liquid
hydrocarbons can be obtained.
Oil shale is commonly defined as a fine-grained sedimentary rock containing organic matter. The organic
matter of oil shale, which is the source of liquid and gaseous hydrocarbons, typically has a higher hydrogen
and lower oxygen content than that of lignite and bituminous coal. Most of the organic matter is insoluble
in ordinary organic solvents; therefore, it must be decomposed by heating to release such materials. The
oil shale is a great potential for the economic recovery of energy, including shale oil and combustible gas,
as well as a number of byproducts. The most economic potential oil shale reservoirs are generally the ones
that is at or near enough to the surface to be developed by open-pit or conventional underground mining
or by in-situ methods. Oil shales were deposited in a variety of depositional environments, including freshwater
to highly saline lakes, marine basins and shelves, and in coastal swamps, commonly in association
with deposits of coal. Oil shales range widely in organic content and oil yield. Commercial grades of oil
shale, as determined by their yield of shale oil, range from about 100 to 200 liters per metric ton (liter/ton)
of rock. The U.S. Geological Survey has used a lower limit of about 40 liter/ton for classification of Federal
oil-shale lands. Others have suggested a limit as low as 25 liter/ton.
Optimum heating and soaking periods were selected according to the highest oil production. Because
thermal cracking, which is also known as pyrolysis, takes place over 1200 o F to produce shale oil, heat and
soak periods belonging to these experiment were selected as optimum periods. There are two different
soaking periods determined as the optimal experimental operation period. The first one starts at 400 o F.
This soaking period that is 40 minutes helps to vaporize water. The second soaking period begins at 1200
o F (650 o C), which is the pyrolysis temperature required for the decomposition of the kerogen. To vaporize
the water or decompose the kerogen needed, time is given with the help of soaking periods. Below the
pyrolysis temperature, it is impossible to produce oil from oil shale samples.
In this study, the recovery characteristics of Himmetoğlu and Hatıldağ oil shale samples were tested
experimentally using the retort technique in the laboratory. Himmetoğlu and Hatıldağ oil shales showed
different oil recovery results. Himmetoğlu Oil shale yielded remarkably higher produced oil recoveries
compared to the Hatıldağ Oil Shale samples. The oil content of the samples were determined by atmosheric
distillation of the oil from the sample. The oil distilled from a sample is collected in a calibrated receiving
tube where its volume is measured. Temperatures up to 1200 o F (about 650 o C) were used to distill the oil
from the sample. This causes some coking and cracking of the oil and loss of small portion of the oil.
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