Planned heating control strategy and thermodynamic modeling of a natural gas thermal desorption system for contaminated soil

This paper presents a planned heating control strategy applied for a natural gas thermal desorption system for polluted soil to achieve the dynamic adjustment of the heating time and energy consumption. A lumped-parameter model for the proposed system is established to examine effects of the natural gas mass flow rate and the excess air coefficient on the heating performance of the target soil. The control strategy is explored to accomplish the heating process as expected with constant temperature change rate or constant volumetric water content change rate at different phases by adapting the natural gas flow. The results demonstrate that the heating plan can be realized within the scheduled 36 days and the total natural gas consumption can be reduced by 24% (1487 kg) compared to that of the open-loop reference condition, which may be widely applied for other thermal remediation systems of the polluted soil.