INFLUENCE OF OIL SHALE SEMI-COKING PARAMETERS ON THE QUALITY OF SHALE SEMI-COKE

Abstract

The relevance of this work is primarily caused by the growing global interest in processing low-grade solid fuels – oil shale, brown coal, etc. The active use of this type of raw material will allow diversifying the structure of the country's economy and increasing the total reserves of fuel, energy and chemical resources, especially given the inevitable reduction in the reserves of traditional hydrocarbon resources-oil and gas. According to experts, Russia has large reserves of oil shale, which are mainly concentrated in the following shale basins, million tons: Baltic (10246,7), Volga (25822,4), Vychegod (58105,8), Timan-Pechora (4888,0), Central (59,6), South Ural (47,55), Olenek (380000,0), Sinsko-Botomsky (220000,0), which also makes the search for effective ways of processing oil shale relevant. The main aim of the research is to determine the influence of oil shale semi-coking parameters (temperature and duration of the process) on the quality of the obtained shale semi-coke, as well as to study the behavior of the organic matter of the obtained samples of shale semi-coke during heating. Objects: oil shale of the Leningrad deposit of the Baltic basin, located on the territory of the Leningrad, Pskov and Novgorod regions. The main characteristics of the object of the research: humidity – 2,00 wt. %, yield of volatile substances – 41,43 wt. %, ash content – 50,5 wt. %, actual density – 1,64 g/sm3. Methods. The authors have used a laboratory installation for semi-coking solid low-grade raw materials with a system for cleaning gaseous products from ammonia, carbon monoxide and benzene to carry out oil shale semi-coking. The characteristics of the obtained samples of shale semi-cokes were determined according to modern domestic and foreign methods. The paper introduces the results of the experimental study of the influence of oil shale semi-coking parameters of the Leningrad deposit on the characteristics of the obtained samples. Two semi-coking regimes: regime I –temperature (450–470) °C, holding time (3, 5, 8 hours); regime II – (510–520) °C, holding time (3, 5, 8 hours), were used. Shale semi-cokes obtained in the first regime have the following properties: humidity (1,15…0,78) wt. %, yield of volatile substances (41,50…37,05) wt. %, ash content (57,56…46,30) wt. %, actual density (1,71…1,98) g/sm3. The semi-coke obtained in the second regime has the following characteristics: humidity (1,08…0,98) wt. %, yield of volatile substances (42,8…38,98) wt. %, ash content (51,56…53,95) wt. %, actual density (1,71…1,99) g/sm3. It was also found that with the increase in the time of the semi-coking, there is the growth in the content of the components of the inorganic part of the semi-cokes and the decrease in the carbon content in the organic part of the shale semi-cokes. Thermogravimetric curves of the obtained shale semi-coxes showed the presence of two exothermic peaks corresponding to the release of moisture and easily bound volatiles (the first peak) and the release of the main volume of shale resin (the second peak) and one endothermic peak – the decomposition of the mineral component of oil shale.

Keywords

• oil shale
• leningrad deposit
• low-grade raw materials
• rational use of natural resources
• integrated use
• semi-coking
• semi-coke
• resin