Shale oil
The resulting oil can be used immediately as a fuel or upgraded to meet refinery feedstock specifications by adding hydrogen and removing impurities such as sulfur and nitrogen.
[4] In the 10th century, the Arabic physician Masawaih al-Mardini (Mesue the Younger) first described a method of extracting oil from "some kind of bituminous shale".
[7] The British Crown granted a patent in 1694 to three persons who had "found a way to extract and make great quantities of pitch, tarr and oyle out of a sort of stone.
"[7][8][9] Later sold as Betton's British Oil, the distilled product was said to have been "tried by diverse persons in Aches and Pains with much benefit.
[7][12][13] During the late 19th century, shale-oil extraction plants were built in Australia, Brazil and the United States.
China, Estonia, New Zealand, South Africa, Spain, Sweden and Switzerland produced shale oil in the early 20th century.
[11][14][15] In response to rising petroleum prices at the turn of the 21st century, extraction operations have commenced, been explored, or been renewed in the United States, China, Australia and Jordan.
Thermal dissolution involves the application of solvents at elevated temperatures and pressures, increasing oil output by cracking the dissolved organic matter.
[22] Royal Dutch Shell reported an EROEI of three to four in 2006 on its in situ development in the "Mahogany Research Project.
A typical shale oil composition includes 0.5–1% of oxygen, 1.5–2% of nitrogen and 0.15–1% of sulfur; some deposits contain more heteroatoms than others.
The US EPA has concluded that raw shale oil has a mild carcinogenic potential, comparable to some intermediate petroleum refinery products, while upgraded shale oil has lower carcinogenic potential, as most of the polycyclic aromatics are believed to have been broken down by hydrogenation.
[36] Particulates in the raw oil clog downstream processes; sulfur and nitrogen create air pollution.
[31] Hydrodesulfurization and hydrodenitrogenation can address these problems and result in a product comparable to benchmark crude oil.
[40] Upgrading shale oil into transport fuels requires adjusting hydrogen–carbon ratios by adding hydrogen (hydrocracking) or removing carbon (coking).
[47] In March 2011, the United States Bureau of Land Management called into question proposals for commercial operations in Colorado, Utah and Wyoming, stating that "(t)here are no economically viable ways yet known to extract and process oil shale for commercial purposes".
