Global Journal of Researches in Engineering, E: Civil & Structural, Volume 23 Issue 2

Figure 2: Example of an oil shale operation in Estonia (Eesti Energia) Bituminous shale (also oil shales, pyro schists, Kero bituminous) are fine-grained sedimentary rocks containing enough organic matter, kerogen, to provide oil and gas fuel. Oil shales vary considerably from one another, in terms of their chemical composition, mineral content, age, type of kerogen and manner of deposition. The existing kerogen in oil shale can be converted into oil through the chemical process of pyrolysis; the decomposition of organic matter under the effect of heat. In fact, the kerogen in oil shale is a kind of "unfinished oil" that has not been exposed to the sufficient temperature and pressure conditions to be transformed into petroleum. Oil shale can also be burned directly as a low- grade fuel for the supply of electricity and heating. It can be used as a raw material in the chemical industries for subsequent extractions (Sulfur, Ammonia, Sealants, Road Bitumen, Cement or Bricks). Oil shale contains kerogen, which must be processed before oil can be obtained, whereas tar sands and shale gas are directly exploitable, containing trapped bitumen and gas respectively. The following products can be obtained from oil shale oil:  Conversion to hydrocarbons through the chemical process of pyrolysis  Low-grade combustion for electricity generation  Use as raw materials (chemical industries, agriculture, construction). Oil shale is still minimally exploited despite the size of its reserves. This is due to a double fold issue. Oil production from oil shale becomes economically viable once the price per barrel reaches the profitability threshold. As for the environmental challenge, the combustion and thermal processing of oil shale generate waste and emit carbon dioxide into the atmosphere. Despite these constraints, industrial processing has already been launched, such as: − Liquid hydrocarbon production in Estonia, Brazil and China − Electricity production in Estonia, China, Israel and Germany − Cement production in Estonia, Germany and China. − Chemical industry in China, Estonia and Russia. b) The Timahdit Oil Shale Case in Morocco The oil shales of Timahdit (Morocco) may constitute significant hydrocarbon resources, amounting to more than nineteen billion tons of raw rock. This is equivalent to around 8.9 billion barrels [1]. These argilo- carbonate sedimentary rocks were formed at the end of the secondary period.) They are essentially made up of [3]: − 30 to 75% terrigenous (clayey) material: aluminosilicates predominate − 25-50% carbonate matter: calcite is the main constituent − Organic matter from 12 to 24%. One part is soluble in organic solvents, the other is insoluble in the same solvents and constitutes kerogen. The mineral composition of an average sample of Timahdit oil shale [1] is shown in Table 1 below: The concentration of dolomite is low when compared with that generally found in the Colorado shale in the USA. Thermal decomposition of dolomite and calcite is a highly endothermic reaction. Maximum temperatures in the combustion zone are, therefore, higher for Timahdit shales than for Colorado shales when the applied process is direct heating. Similarly, the Table 1: Mineral composition of the Timahdit shale Mineral Pourcentage (%) Dolomite (CaMg (CO 3 ) 2 ) 15,9 Calcite (CaCO 3 ) 41,5 Quartz (SiO 2 ) 19,5 Illite ((OH) 4 K 2 (Si 6 Al 2 ) Al 4 O 20 ) 13,4 Pyrite (FeS 2 ) 1,8 FeCO 3 + FeO 3 1,8 TiO 2 + Phosphate 2,4 Other elements 3,7 © 2023 Global Journals Global Journal of Researches in Engineering ( ) E Volume XxXIII Issue II Version I 45 Year 2023 The use of Oil Shale for Road Coating