Optimization of conditions of a modified Rudin method to measure the foam stability using response surface methodology

A central composite design was employed to optimize the conditions of a modified Rudin method to measure the foam stability with three factors:CO2 flow, gas outlet pressure of total valve, temperature of sample pretreatment. The combined effects of these variables on foam stability were investigated. Results showed that the generated regression models adequately explained the data variation and significantly represented the actual relationship between the independent variables and the responses. The results indicated that the effect order of three factors was as follows:gas outlet pressure of total valve, CO2 flow, and temperature of sample pretreatment. The canonical analysis revealed that the optimal conditions for measurement were:gas outlet pressure of total valve 0. 3MPa, CO2 flow 340mL/min, temperature of sample pretreatment 20℃. Under optimal conditions, the predicted value of foam stability was 111.363s, the testing value was 110.813s, and their relative error was 0.49%. The equation and the regression model were fitted well, and could be applied in practical experiment.