What Is Oil Shale?
Oil shale is produced from sedimentary rocks containing kerogen, an organic precursor to oil that releases petroleum –like liquids in one of three ways:
1) pyrolysis (heating of the rock)
2) hydrogenation (reduction of chemical elements)
3) thermal dissolution (hydrogen refining process)
Image source: http://ostseis.anl.gov/guide/oilshale/
Organic debris and silt formed at the bottom of lake and seabeds millions of years ago. Through pressure and heat they were converted into oil shale.
Oil shale is known as “the rock that burns” because it contains enough oil to burn as is. To use the liquid form of oil shale it needs to go through a process of refinement. The solid rock is mined and then heated to 530 to 930 degrees Fahrenheit. Huge amounts of water are driven underground at high pressures to melt the rocks until they form a liquid which is further separated and then collected. The three processes mentioned above (pyrolysis, hydrogenation and thermal dissolution) will each produce oil shale with varying properties.
What Is Oil Shale Used For?
Oil shale was first used in the 17th century but true exploitation began in France in 1839, in Scotland in 1859 and then in Australia in the 1860’s. During this time the most common products created from oil shale were paraffin, kerosene and lamp oil, lubricating oil and grease, fuel oil, naphtha, illuminating gas, and ammonium sulphate.
Today oil shale is used to produce oil, and as an energy source in both thermal and electrical power plants. Other uses include cement, bricks, fertilizers, soil additives, carbon fibres, absorbent carbons, carbon black, decorative and construction building blocks, rock wool insulating materials and glass.
Where Is Oil Shale Produced?
Oil shale resources are found in many countries however there is no economical method for extracting oil from the oil shale rocks. The lack of commercial practicalities has inhibited the development of better technologies to reduce the cost of extraction. Another deterrent is the large environmental damage encountered in the mining process.
The United States has the largest oil shale reserves and the largest producers are China, Estonia, Brazil and Australia.
Oil shale is a mineral oil that has been around for eons and is produced from kerogen rocks through a process of pyrolysis. Oil shale can be burned as is but most often it goes through further refining procedures to be transformed into liquid oil. This oil is mainly used as a fuel to generate electricity as well as being used in small commercial quantities in cement and brick work, glass, soil additives and carbon black.
Currently it is not economically viable to produce oil shale at full capacity or in large volumes. The largest producer of oil shale is China.
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