Systematic experiments were performed on an innovative pulse detonation steam superheater (PDSS) for determining the concentration limits of detonation of the ternary mixtures propane–oxygen–steam at normal atmospheric pressure. The experiments were carried out while varying the fuel–oxygen equivalence ratio (from 0.3 to 1.7) and the volume fraction of steam (from 0 to 0.7). Cyclic detonation of ternary mixtures was shown to be able to create a high-temperature gas medium that has a temperature above 2250 K and contains to 80% highly superheated steam and to 20% CO2, and also CO, O2, and H2 at low concentrations at atmospheric pressure. Such medium was proposed to be used for advanced treatment of household and industrial organic waste to produce a gas mixture of CO and H2. Because the filling of PDSS with the “cold” ternary gas mixture is periodic, the increase in the temperature of its walls and internals is insignificant, and PDSS can be built from conventional (not necessarily refractory) construction materials.