Prediction of the formation of low-molecular components, particles, and condensed phases during thermal destruction of oil-contaminated soil

Abstract

In this study, thermodynamic modelling of the process of thermal destruction of oil-contaminated soil of Ozenmunaigas JSC, which includes compounds such as carbon, silicon, aluminum, iron, calcium, magnesium, sodium, potassium, chromium, phosphorus, manganese, copper, titanium, molybdenum, nickel, vanadium, and water, was carried out. The physicochemical and thermodynamic parameters of the complex system were calculated at P=0.1 MPa, T=598-3000 K. The concentration distribution of components, particles, and condensed phases in the gas phase has been established. In the process of thermal destruction of oil-contaminated soil, the formation of condensed phases was as follows: SiO2(c), Al2O3(c), AlO3H3(c), Cu(c), Cu2O(c), FeO(c), Fe2O3(c), Fe3O4(c), Fe2SiO4(c), NiO(c), MnO(c), Mn3O4(c), MnO2H2(c), Cr2O3(c), MoO2(c), V2O3(c), V2O4(c), TiO2(c), MgSiO3(c), Mg2SiO4(c), MgTi2O5(c), Ca3P2O8(c), Mg2SiO4(c), MgTi2O5(c), Ca3P2O8(c), CaCO3(c), CaSiO3(c), CaTiO3(c), Na2Si2O5(c), K2Si4O9(c). At the same time, the amount of condensed calcium silicate CaSiO3(c) was significant and amounted to 3.2 mol/kg, which is due to the initial standard content of oxides of the type (g/kg): SiO2-473,7, CaO-181,5 in oil-contaminated soil. The formation of various types of condensed phases (from 10-30 to 10-4 mol/kg) during thermal degradation can help reduce the synergism and toxicity of metal particles in oil-contaminated soils. In the process of thermal destruction of oil-contaminated soil, its carbon-containing components (mg/kg: С12-6,27; С13-10,98; С14-15,69; С15-18,82; С16-23,52; С17-31,37; С18-27,80; С19-17,25; С20-29,80) were mainly converted into oxide, carbon dioxide, and water, and thereby neutralized the organic mass of the soil.