Simulation and optimization of hydrogen sulfide-containing tail gas treatment process based on improved complex iron method

Objective  The aim is to effectively treat hydrogen sulfide-containing tail gas and ensure safe, stable, long, full, and excellent operation of the plant.

Methods  Based on the Peng-Robinson thermodynamic model, Aspen Plus V11 software was used to simulate the whole process of hydrogen sulfide treatment in the improved complex iron device, and the response surface design was executed according to Box-Behnken Design to obtain the optimal hydrogen sulfide removal rate and its corresponding optimized operating parameters.

Results  The simulation process could better reflect the actual operation of the improved complex iron device and could be used as a basic model for subsequent optimization studies. When the circulating solution temperature was 47.2 ℃, the Fe³⁺ mass fraction in circulating solution was 8.410 0%, the circulating solution volume flow rate was 3.12 m³/h, and electrolytic tank voltage was 0.64 V, the hydrogen sulfide removal rate of the improved complex iron device was as high as 99.999 988%. At this time, the mass concentration of hydrogen sulfide in the external exhaust was 9.5 mg/m³, which could fully satisfy the constraint that the mass concentration of hydrogen sulfide in the external exhaust was not more than 10 mg/m³. The t-test results showed that there was no significant difference between the predicted value optimized by the response surface methodology and the verification value, and the accuracy was consistent.

Conclusions  The results of this study can provide accurate and reliable theoretical support and data sources for further improving the level of the hydrogen sulfide-containing tail gas treatment.