Optimization of supercritical carbon dioxide extraction process of oil-based drilling cuttings oil phase based on response surface methodology

Objective  The process parameters of supercritical carbon dioxide extraction of oil phase from oil-based drilling cuttings were optimized.

Methods  The response surface method was employed to test the important parameters affecting the supercritical carbon dioxide extraction process, and the numerical simulation was carried out according to the test results. The optimization condition of extraction time, pressure, temperature, supercritical carbon dioxide flow rate, and other parameters were obtained by simulation.

Results  The response surface analysis was used to analyze the influence of each variable on the extraction effect. Based on the extraction data, a quadratic polynomial model was established to fit the experimental results better. The optimum extraction conditions were identified to be with extraction pressure of 25 MPa, temperature of 323.15 K, time of 90 min, and flow rate of 25.0 L/h.

Conclusions  The optimum extraction conditions were obtained by combining the specific experimental data with the response surface method. Under this condition, the maximum oil removal rate was 95.22%. There was no significant change in the traits before and after the extraction based on GC-MS analysis. Supercritical carbon dioxide was proven to be effective in solid-liquid separation and resource recovery.