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Tallinn, Estonia

Eesti Energia AS is a private limited energy company in Estonia with its headquarters in Tallinn. It is the world's biggest oil shale to energy company. The company was founded in 1939. As of 2014, it operates in Estonia, Latvia, Lithuania, Finland, Jordan and Utah, United States. In Estonia the company operates under the name Eesti Energia, while using the brand name Enefit for international operations. The main raw material for energy production – oil shale – is extracted from mines located in Eastern-Estonia and owned by the company. The group of Eesti Energia has three main operation areas: electricity generation, shale oil production, and sale and distribution electricity. Its shares are owned by the Government of Estonia. Wikipedia.

Puura V.,University of Tartu | Soesoo A.,Tallinn University of Technology | Voolma M.,Tallinn University of Technology | Hade S.,Tallinn University of Technology | Aosaar H.,Eesti Energia
Oil Shale | Year: 2016

The concession area of the Jordan Oil Shale Energy Co (JOSE) is located in the southern border zone of the Attarat Um Ghudran deposit, next to the Wadi Maghara deposit, both consisting of marinite type oil shale (OS). These deposits of the Upper Cretaceous to Lower Paleogene Muwaqqar Chalk-Marl Formation form a huge north-southward elongated oil shale basin in Central Jordan, with resources over 55 billion tons. JOSE has drilled a regular grid of boreholes with a full coring of the up to 90 m thick OS seam and its lower and upper contact layers. Visually, the OS unit is a rather homogenous dark-colored (grey, black, brownish grey) succession of finely bedded (laminated) kerogen-bearing carbonate rocks that has been in earlier papers described as a uniform lithological unit. The aim of the geological and lithological studies of the JOSE exploration area was (i) to investigate the vertical variation of OS composition and, if present, to define layers within the OS unit, and (ii) to identify lithological varieties and chemical composition of OS present in different layers. On the basis of field evidence, downhole gamma-logging, chemical analyses and other criteria, an original detailed scheme of the layered structure of oil shale and barren rocks was introduced. A total of eight OS layers (indexed as A, B1, B2, C, D, E1, E2, E3) and at least four barren dolomitic limestone interlayers were distinguished. The present publication is dedicated to the chemical study of the layers and the total OS seam. A representative gapless collection of 632 conventional core samples from 12 cores serves as the base for the comparative study of the layers. Two main (SiO2, CaO) and two subordinate chemical (Al2O3 and P2O5) components of the mineral matter (MM), and loss on ignition (LOI 500 °C) approximately reflecting the content of organic matter (OM), are the basic variables discussed. Contents of SiO2 and CaO always show negative correlation, whereas local enrichment with Al2O3 and P2O5 occurs in certain interbeds. OM content in samples has no strong correlation with mineral matter abundances. The eight distinguished OS layers comprise both those strongly enriched in CaO, or oppositely in SiO2. The layers differ in rate of internal heterogeneity reflected in variation of standard deviation values. With rare exceptions, the barren limestone interlayers are dolomitized, strongly enriched with MgO and depleted of CaO. The database on the distribution of mineral compounds and trace elements serves for the 3-D block modelling of the deposit composition. However, further data analysis is required for the understanding of lateral changes of the layers’ mineral composition, and geological and geochemical structure. © 2016 Estonian Academy Publishers. Source

Uibu M.,Tallinn University of Technology | Somelar P.,University of Tartu | Raado L.-M.,Tallinn University of Technology | Irha N.,Estonian National Institute of Chemical Physics and Biophysics | And 3 more authors.
Construction and Building Materials | Year: 2016

The combustion of oil shale (OS) in electric power plants is accompanied by the generation of vast amounts of waste ash. One promising idea to maximize the recovery of oil shale from mines is to backfill them with oil shale ash (OSA)-based concrete. However, the properties of this concrete have yet to be analyzed in detail and this approach also raises concerns about the risk of polluting both surface and groundwater. To address these concerns we developed different types of OSA-based concretes and characterized their structure and leaching characteristics. This information enables us to predict the type and durability of each respective ash stone. A compressive strength of 1-5 MPa was achieved after 7 days (maximum after 28 days > 25 MPa). During the early stages of curing, the pH and electrical conductivity (EC) of the leachates exceeded or were close to the limits set for general wastes, however, both properties decreased considerably after 28 days (pH < 11.5; EC < 1000 μs/cm). In order to utilize OSA on a large scale, the composite blends we developed should be further optimized by adding ground high-calcium fly ashes, Portland cement, or other components. © 2015 Elsevier Ltd. All rights reserved. Source

Sidorkin V.T.,ENTEH Engineering AS | Tugov A.N.,JSC All Russia Thermal Engineering Institute | Moshnikov A.N.,Eesti Energia | Vereshchetin V.A.,JSC All Russia Thermal Engineering Institute | Bersenev K.G.,ENTEH Engineering AS
Power Technology and Engineering | Year: 2016

The results of studying the effect of flue gas recirculation on the amount of nitrogen oxides (NOx) formed in a TP-101 steam boiler are presented. In firing oil shale, the recirculation of flue gas to the mills makes it possible to inject the portion of the primary air replaced by this gas to the furnace above the oil-shale burners, thus providing staged firing. This measure allows reaching a NOx concentration limit of about 170 – 190 mg/m3. During co-firing of oil shale and retort gas (60:40 of total heat input), the recirculation of flue gas to the burners reduces the NOx concentration at the boiler outlet from 500 to 230 – 240 mg/m3. © 2016 Springer Science+Business Media New York Source

Toom K.,Estonian University of Life Sciences | Jurjenson K.,Estonian University of Life Sciences | Juhanson T.,Eesti Energia | Annuk A.,Estonian University of Life Sciences
Engineering for Rural Development | Year: 2011

Under certain circumstances, the transmission system operator (TSO) can face the need to reduce the power output of the wind parks. In a market based setup the wind power producers will normally pay for the balancing costs of wind power. Therefore, the more accurate the forecast of wind power, the lower the balancing costs for the wind power producers will be. From a socio-economic perspective, better forecasting will reduce the total generation costs due to the more optimal dispatch of power plants. The operators of the wind parks integrated into the transmission network are responsible for presenting a 24h-forecast of their output power to TSO. The real wind power differs from the forecast one. This difference needs balancing by the rest of the energy system. In the Estonian conditions, it means the regulation of the capacity of oil-shale-fuelled power plants which induces an accelerated wear, additional emissions and fuel consumption of the power plants. The reason why wind park output power is particularly difficult to forecast at wind speeds of 6-10 m·s -1 is due the fact that electricity generation of wind turbines changes markedly between these speeds. Source

Roslyakov P.V.,Moscow Power Engineering Institute | Zaichenko M.N.,Moscow Power Engineering Institute | Melnikov D.A.,All Russia Thermal Engineering Institute | Vereshetin V.A.,All Russia Thermal Engineering Institute | Attikas R.,Eesti Energia
Thermal Engineering | Year: 2016

The article reports the results of investigation into the possibility of using off-design coals as an additional fuel in connection with predicted reduction in the heat of combustion of shale oil and more stringent environmental regulations on harmful emissions. For this purpose, a mathematical model of a TP-101 boiler at the Estonian Power Plant has been constructed and verified; the model describes the boiler’s current state. On the basis of the process flow chart, the experience of operating the boiler, the relevant regulations, and the environmental requirement criteria for evaluation of the equipment operation in terms of reliability, efficiency, and environmental safety have been developed. These criteria underlie the analysis of the calculated operating parameters of the boiler and the boiler plant as a whole upon combustion with various shale-oil-to-coal ratios. The computational study shows that, at the minimal load, the normal operation of the boiler is ensured almost within the entire range of the parts by the heat rate of coal. With the decreasing load on the boiler, the normal equipment operation region narrows. The basic limitation factors are the temperature of the steam in the superheater, the temperature of the combustion products at the furnace outlet and the flow rate of the combustion air and flue gases. As a result, the parts by heat rate of lignite and bituminous coal have been determined that ensure reliable and efficient operation of the equipment. The efficiency of the boiler with the recommended lignite-to-coal ratio is higher than that achieved when burning the design shale oil. Based on the evaluation of the environmental performance of the boiler, the necessary additional measures to reduce emissions of harmful substances into the atmosphere have been determined. © 2016, Pleiades Publishing, Inc. Source

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