Oil shale industry

Oil shale is used industrially in Brazil, China, Estonia and to some extent in Germany, Israel and Russia. Several other countries are currently researching their reserves and production methods to improve efficiency and recovery.[1] Australia though has halted their pilot projects due to environmental concerns.[2] Estonia accounts for about 70 % of the world's oil shale production.[3]

Oil shale has been used in industry since the early 1600s when it was mined for its minerals. Since the late 1800s shale oil has also been used for its oil content and as a low grade fuel for power generation. Power generation is not particularly wide spread, however it is present in countries that have significant oil shale deposits, and little in the way of other hydrocarbon deposits. Similarly, oil shales are being seen as a solution to increase domestic production of oil in countries that are reliant on imports.

Oil shale has been used since ancient times. The modern industrial oil shale mining began in 1837 at the Autun mines in France, followed by Scotland, Germany and several other countries.[5][6] The first oil shale retort was constructed in the United States in 1855.[6] The second wave of oil shale industry started just before the World War I, but was phased-out in most of countries after the World War II because of high processing costs and the discovery of large supplies of easily accessible crude oil.[4][6][5][7] The oil shale production continued to grow only in Estonia, Russia and China. Due the 1973 oil crisis, oil shale industry was restarted in several countries, but was mainly shut down in mid of 1980s. The global oil shale industry started to increase slightly only in mid of 1990s. In 2003, the oil shale development program was initiated in the United States, and the commercial leasing program for oil shale and tar sands was introduced in 2005.[8][9]

[+] Mining

The oil shale is mined either by traditional underground mining or surface mining techniques. There are several mining methods, but the aim of all of them is the fragmenting of oil shale deposit to enable the transport of shale fragments to a power plant or retorting facility. Main methods of surface mining are open pit mining and strip mining. The main sub-surface mining method is the room-and-pillar method.[10] The largest oil shale mine in the world is the Estonia underground mine in Estonia, operated by Eesti Põlevkivi.[11]

[+] Power generation

Oil shale could be used as a fuel for thermal power plants, where the shale is burned like coal to drive steam turbines. In 1924, the Tallinn Power Plant was witched to oil shale firing as a first power plant in the world. [12] Currently there are oil shale-fired power plants in Estonia with an installation capacity of 2967 Megawatts, Israel (12.5 MW), China (12 MW), and Germany (9.9 MW).[13][14][15] While some countries have closed their oil shale-fired power plants (e.g. Romania) or converted to other fuels (e.g. Russia), some other countries are looking for construction of these power plants (e.g. Jordan and Egypt), or burn oil shale at the power plants together with coal (e.g. Canada and Turkey).[13][16][17]

There are four technologies for combustion:[18]

* Pulverized Combustion (PC)—used in the older units of oil shale-fired power plants in Estonia;
* Fluidized Bed Combustion (FBC)—used by Rohrbach Zement in Dotternhausen, Germany;
* Circulated Fluidized Bed (CFBC)—used in two new units at Narva Power Plants in Estonia, Huadian Power Plant in China, and PAMA power plant at Mishor Rotem in Israel;
* Pressurized fluidized-bed combustion (PFBC)—more advanced and efficient, but premature technology.[19]

The most modern used technology of a combustion of oil shale in power plants is a pressurized fluidized-bed combustion (PFBC). The most modern used technology of a combustion of oil shale in power plants is a bubbling fluidized bed (BFB) or circulating fluidized bed (CFB) process, while the traditional way of burning oil shale is through pulverized combustion.[20][13]

[+] Oil extraction

Main article: Oil shale extraction

At present, the major shale oil producers are Estonia, Brazil and China, while Australia, USA, Canada and Jordan have planned to start or restart shale oil production.[13][16] Although there are several oil shale retorting technologies, only five technologies are currently in commercial use, which are Kiviter, Galoter, Fushun, Petrosix, and Alberta Taciuk.[21] The two main methods of extracting oil from shale are ex-situ and in-situ.

[+] Other industrial uses

Oil shale is or could be used for production of different products like specialty carbon fibers, adsorbent carbons, carbon black, cement, bricks, construction and decorative blocks, soil additives, fertilizers, rock wool insulating material, glass, and pharmaceutical products. However, oil shale usage for production of these products are still small or even in experimental stages only.[4][17]

Some oil shales are suitable for sulfur, ammonia, alumina, soda ash, and nahcolite production as shale oil extraction byproducts. Some oil shales could be used for uranium and other rare chemical element production. In 1946-1952, a marine type of Dictyonema shale was used for uranium production in Sillamäe, Estonia, and in 1950-1989 alum shale was used in Sweden for the same purpose.[4] Oil shale gas could be used as a substitute for natural gas, however at the current price level this is not economically feasible.[22][23]