Production history experience
Our oil shale experience in Estonia spans 100 years
The History of
Oil Shale in Estonia
Estonia, uniquely in the world, has already been using oil shale to produce electricity, heat, gas and oil for nearly a century, meaning that the properties of oil shale are very well known to our energy industry. Over several decades of continuous improvement, the Enefit technology has been developed into the best technology available and is known for its stable and reliable production.
The mining of oil shale in Estonia started in 1918, when the first open pit mine was opened in Pavandu. The oil shale then had a narrow range of uses and was used for heating houses, powering locomotives, as well as a heat source for the cement industry. Six years later, in 1924, the first shale oil plant was opened in Kohtla-Järve. It produced soak oil, low quality petrol and oil for heating. In the same year, the Tallinn power station was the first to change over to use of oil shale as its feedstock.
Before World War II there were many companies operating different types of plants to produce shale oil. Some of them are still operational today. After the war the use of oil shale in Estonia increased constantly until 1980 when production reached a peak of 31 million tons, which represented 65% of the worldwide total. Currently, mining is limited to 20 million tons per year until 2015.
Between 1946 and 1951 two Kiviter-type retorts were built to produce shale oil. In the 1980s three more retorts of the same type were built.
The first Galoter-type retorts, the predecessor of Enefit technology, were built between 1953 and 1963 in Kiviõli, and following their trials the UTT-3000 plant was built in 1980, near the Eesti power plant, processing 3000 tons of oil shale per day. The new solid heat carrier technology Enefit280 was able to draw on more than 30 years of operating experience with the Galoter process when it was developed in 2009.
As the drive for energy and fuel independence increases, new methods become ever more necessary, and the Enefit technology offers one solution for countries that have large supplies of oil shale.
The Development of Enefit Technology
Throughput: 500 t/d
Throughput: 140 t/h
Capacity doubled to 280t/h
Environmental impact lessened
The History of
Enefit280 – more than 50 years of research and development. After vertical oil shale retorts for processing bulk oil shale were developed and industrialised, the need to develop a retorting process capable of processing fine grain sized (0-25 mm) oil shale was identified. This led to the development of solid heat carrier retorting technology.
The Galoter Process
Research into the use of a solid heat carrier process for the pyrolysis of brown coal, peat and oil shale began in 1944, towards the end of World War II, in the G. M. Krzhizhanovski Power Engineering Institute (ENIN) in the Soviet Union. The process developed was named the Galoter process.
A number of Estonian organizations and companies participated alongside ENIN in the research and development work for the Solid Heat Carrier (SHC) process. The participation of Estonian specialists was quite logical because, prior to World War II, large scale oil shale mining and processing industries existed only in Estonia and the Leningrad district of the Soviet Union.
The laboratory and bench-scale investigation of the SHC process were carried out at the ENIN laboratories until 1947, when a pilot plant with a processing capacity of 2.5 t/day was built in Tallinn at the Ilmarine engineering plant. This pilot plant remained in operation until 1956.
Practically all the equipment of the UTT-200, the next demonstration plant, was modelled on this unit.
In 1953 the scaled up UTT-200 unit was built in Kiviõli in Estonia. From 1953 to 1963 the UTT-200 operated successfully at Kiviõli and the initial data for the design of the second generation UTT-500 unit was collected. This UTT-500 unit was built and commissioned in 1963 and was also in Kiviõli. The long running operation and maintenance of this unit from 1963 to 1981 served as the basis for the design of the third generation UTT-3000 unit.
When the two oil shale fired power plants were built in Narva in Estonia in 1965 and 1973, the need to produce start-up fuel for the plants' boilers became evident. This gave ENIN the opportunity to propose building two third generation UTT-3000 units in Narva at the Eesti power plant, and so the construction of the UTT-3000 units started in 1976 and was completed in 1980.
Transition to Enefit140
The UTT-3000 retorts claiming a unit throughput rate of around 3000 tons per day of raw oil shale started operation in late 1979. The design data gave an operating time for each retort of 6800 hours per year, and the two retorts were expected to operate simultaneously.
The initial design of the UTT-3000 contained numerous flaws and shortcomings, which resulted in constant breakdowns and repairs to the equipment. The main problems were the accumulation of fine ash and coke particles and the formation of coke on equipment surfaces, which caused clogging of the equipment, while severe problems were also encountered in sealing the gas flows between the high and low pressure zones within the equipment. The flaws in the original design caused severe wearing of the transportation equipment for solids. The high ash content in the pyrolysis oil vapours caused maintenance problems in the oil condensation section of the plants.
All these flaws in the original design of the UTT-3000 meant that the annual production in the first year of operation was less than 1% of the designed capacity. In 20 years of plant operation, engineers managed to raise production volumes up to around 35% of the designed capacity.
Since more than 70% of the original UTT-3000 design had been changed and reworked by that time and the Galoter process patent had expired, Eesti Energia AS, the owner of the Narva power plants and the UTT-3000 facilities, applied for a patent for the improved Solid Heat Carrier process, then named the TSK process. The patent was granted in 2005.
As part of the rebranding of Eesti Energia in 2009, the new technology was named Enefit140.
In 2007, Narva Õlitehas AS was established as a separate subsidiary of Eesti Energia to operate the Enefit140 oil plant.
Development of Enefit280
Between 1999 and 2008, due to the rise of oil and fuel prices along with the growth of energy use around the world, the company realized the full business potential of shale oil production. Development of the new generation SHC technology was emphasized.
In 2008, Eesti Energia started developing the new Enefit280 technology in partnership with the Finnish engineering firm Outotec
Oyj. In 2009, Eesti Energia and Outotec established a joint venture company, Enefit Outotec Technlogy, to develop and market the new technology.
Construction work for the first Enefit280 plant started in Narva in October 2009, and the plant produced its first oil in 2012.