Modeling on thermal conductivity of petroleum hydrocarbons-contaminated soils considering preferential invasion pores and connection patterns

Petroleum hydrocarbons (PHs) are compounds containing the elements carbon and hydrogen. The leaks of PHs during the PHs exploration, transportation, refining, and storage process usually contaminate the site, disrupt ecological environment and threaten human health. Therefore, the in-situ thermal desorption technology has been widely used to heat the contaminated sites and remove the pollutants, but the contaminants removal efficiency is controlled by thermal conductivity (TC) in the contaminated site. In this study, a theoretical model was developed by using different preferential invasion pores (i.e., parallel and series pores) and connection patterns between air and liquid mixture of water and PHs (i.e., parallel and series connections). The new model was expressed as a function of porosity, temperature, degree of saturation of PHs, and degree of saturation of water. The theoretical model was evaluated with TC values of diesel-contaminated soils, and good agreements between estimated and measured TC values were obtained. Moreover, all the estimated TC values determined by the new model strictly fall within the Wiener bounds, and most estimated TC results fall within the Hashin-Shtrikman bounds. The theoretical TC model will contribute to the understanding of heat transfer process in the PHs-contaminated site during the remediation process.