<b>Abstract</b>— <p>In order to purify natural gas from hydrogen sulfide (H₂S), it is proposed to use an energy-efficient and environmentally friendly gas hydrate crystallization technology. Mathematical modeling of the effect of changing propane (C₃H₈) concentration (0–3.50 mol %) on the gas hydrate distribution coefficient of H₂S and the fraction of gas hydrate cavities filled with gases is performed. The model gas mixture of CH₄ (concentration is normalized)–C₂H₆ (2.00 mol %)–C₃H₈ (0–3.50 mol %)–<i>n</i>-C₄H₁₀ (1.00 mol %)–<i>n</i>-C₅H₁₂ (1.00 mol %)–N₂ (3.00 mol %)–CO₂ (0.60 mol %)–H₂S (2.50 mol %) at <i>T</i> = 278.15 K and <i>P</i> = 4.00 MPa is studied. It is found that with an increase in the concentration of C₃H₈ from 0 to 3.50 mol.%, an insignificant decrease in the gas hydrate distribution coefficient of H₂S from 18.71 to 17.32 is observed. H₂S molecules mainly fill small gas hydrate cavities, the filling fraction of which is 0.51. It is shown that in the case of an increase in the concentration of C₃H₈ from 0 to 3.50 mol %, the dissociation pressure of the studied gas mixture significantly decreases from 2.33 to 1.01 MPa. It is concluded that high concentrations of C₃H₈ do not lead to a significant deterioration in the concentration of H₂S in the gas hydrate phase but increase the energy efficiency of the technology due to the lower hydrate formation pressure.</p>