The use of oil shale as a fuel in Estonian Power Plants started at the beginning of the 20th century (e.g. Tallinn Power Plant 1923, Püssi Power Plant 1937). For combusting lump oil shale grate-firing technology was used. The limitations of grate-firing technology forced to search for or to create better combustion technologies. In these years the pulverized-firing combustion technology was already successfully used for coal combustion. Estonia was the first country to implement the oil shale pulverized-firing combustion technology in the new Kohtla-Järve Power Plant (in operation since January 1949). Almost at the same time in the Institute of Industrial Problems (IIP) of the Academy of Sciences of the Estonian SSR (later the Institute of Termophysics and Elektrophysics (ITEF)) and then the Estonian Energy Research Institute (EERI) the experimental and theoretical research of oil shale combustion in fluidized bed was started. In 1948 Dr. Sc. Hans Truu, who was the vice-director of IIP and the head of the Department of Furnaces (later the Department of Combustion Processes (DCP)) introduced the subject of fluidized-bed combustion technology in Estonia. During more than fifty years the fluidized-bed combustion of several oil shales (from Estonia and Syria, Morocco and Volga basin), other fuels (Estonian oil shale semicoke, dictyonema argillite, wood, peat, coal) and their mixtures (Estonian oil shale with semicoke, oil shale with dictyonema argillite, oil shale with coal, wood with peat) was studied along with other technologies (e.g. pulverized-firing of oil shale) up until the incorporation of EERI into Tallinn University of Technology in 2004. During this fifty years eleven scientific theses were defended (seven of them dealing with fluidized-bed combustion technology) and several projects implemented by the scientists of the DCP of the EERI. This article gives a short overview of using fluidized-bed technology for oil shale combustion, studied in IIP (ITEF and EERI).
1. Truu, H. K. Theory and Praxis of Oil Shale Combustion. Doctoral thesis of technical sciences. – Academy of Sciences of the USSR, G. M. Krizizanovsky Institute of Energy, Moscow, 1951. P. 187 [in Russian].
2. The Combustion of Fine Oil Shale in Industrial Fluidized Bed Boiler at Püssi Power Plant. – Scientific Technical Report of the Energy Research Institute of the Estonian Academy of Sciences (compilers Jürismaa, E. and Kartau, T.), Tallinn, 1962. P. 64 [in Estonian].
3. Martins, A. First industrial combustion of oil shale with gasification in fluidized bed // Gazette of Estonian Energy. 1997. Vol. 16, No. 1/2. P. 14–17 [in Estonian].
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5. Martins, A., Uuesoo, R. The fusible characteristics of oil shale fly ash from fluidized bed gasifier. – Proceedings of the 1st All-Union Scientific–Technical Conference about Influence of Fuels Mineral Part on the Operation of Power Plant Boilers. – Alma-Ata, 1971. P. 150–157 [in Russian].
6. Martins, A., Kartau, J., Mere, H. The gasification of oil shale in fluidized bed to get gas for the energetic boilers. - Proceedings of the 4th All-Union Symposium of the Academy of Sciences of the USSR “The Combustion of Gases and Natural Fuels”. Alma-Ata, Chernogolovka, 1980. P. 70–73 [in Russian].
7. Martins, A., Kartau, J., Nurk, A., Uuesoo, R. Gasificator for oil shale in fluidized bed. The Author’s Certificate USSR 709938. 21.08.1978 [in Russian].
8. Martins, A., Kallaste, E., Nurk, A., Mere, H. Elaboration of the Industrial Fluidized Bed Gasifier (Project Task). – The Report of Contract No. 2-81. The Institute of Termophysics and Elektrophysics of the Academy of Sciences of the ESSR. Tallinn, 1981. P. 94 [in Russian].
9. Martins, A., Nurk, A., Kallaste, E., Mere, H. Verbrennung von festen Brennstoffen in der zweistufigen Wirbelschicht // Energietechnik. 1983. No. 7. S. 247–249.
10. Martins, A. Potentials for the fluidized bed technology by burning local fuels – Proceedings of Estonian-Finnish Energy Seminar. Hakapaino OY, Helsinki, 1994. P. 33–41.
11. Syromjatnikov, N. The rational combustion of small-sized fuels. – Proceedings of the Conference of the Universities. Sverdlovsk: Publishing House of the Ural Polytechnic Institute, 1959. P. 62–65 [in Russian].
12. Valk, M. (Ed.). Atmospheric Fluidized Bed Coal Combustion. Research, Development and Application. – ELSEVIR, Amsterdam-Lausanne-New York- Oxford-Shannon-Tokyo, 1995. P. 462.
13. Kallaste, E., Uuesoo, R. The retention of sulphur compounds by calcium oxide in the fluidized bed. – Proceedings of All-Union Scientific–Technical Seminar of Fuels Combustion with Minimal Amount of Harmful Emissions. The Institute of Termophysics and Elektrophysics of Academy of Sciences of ESSR, Tallinn, 1974. P. 19–22 [in Russian].
14. Kallaste, E. The Sulphur Distribution during Oil Shale Gasification in Fluidized Bed. The Thesis of Candidate Technical Sciences (Ph.D). – Tallinn Polytechnic Institute, Tallinn, 1978. P. 157 [in Russian].
15. Öpik, I. Ots, A. The Use of Oil Shale for Energy Production I. – Tallinn: Publishing House “Valgus”, 1967. P. 99 [in Russian].
16. Öpik, I. The Impact of Oil Shale Mineral Part on the Operational Conditions of the Boiler Unit. – Tallinn: Estonian National Publishing House, 1961. P. 249 [in Russian].
17. Nurk, A. The Physical-Chemical Properties of Ash Samples from Fluidized Bed. Abstract of Thesis of Candidate Technical Sciences (Ph.D.). – Tallinn: Tallinn Polytechnical Institute, 1980. P. 19 [in Russian].
18. Martins, A., Nurk, A. The combustion of oil shale ash-laden gases in the cyclone-type wet-bottom furnace // Thermal Energetics. 1976. No. 8. P. 42–44 [in Russian].
19. Rajur, K., Õispuu, L. The Principles of the Fuel Preparation for Combustion in the Fluidized Bed // Abstract of the All-Union Scientific-Technical conference “The Progressive Processes in the Heating Power Engineering.” The Ural Polytechnical Institute. – Sverdlovsk, 1984. P. 25–26 [in Russian].
20. The Industrial-Scale Testing of Fluidized Bed Gasifier for Boiler No. 3 of the Kohtla-Järve Power Plant (designer Leningrad Department of Orgenergostroi). The Contract No. 16/13-83, January 17, 1983 [in Russian].
