Experimental and numerical investigation of shock wave-based methane pyrolysis for clean H\(_2\) production

Shock wave reforming, or the use of shock waves to achieve the necessary high-temperature conditions for thermal cracking, has recently gained commercial interest as a new approach to clean hydrogen (H \(_2\) ${}_2$ ) generation. Presented here is an analysis of the chemical kinetic and gasdynamic processes driving the shock wave reforming process, as applied to methane (CH \(_4\) ${}_4$ ) reforming. Reflected shock experiments were conducted for high-fuel-loading conditions of 11.5–35.5% CH \(_4\) ${}_4$ in Ar for 1790–2410 K and 1.6–4 atm. These experiments were used to assess the performance of five chemical kinetic models. Chemical kinetic simulations were then carried out to investigate the thermal pyrolysis of 100% CH \(_4\) ${}_4$ across a wide range of temperature and pressure conditions (1400–2600 K, 1–30 atm). The impact of temperature, pressure, and reactor assumptions on H \(_2\) ${}_2$ conversion yields was explored, and conditions yielding optimal H \(_2\) ${}_2$ production were identified. Next, the gasdynamic processes needed to achieve the target temperature and pressure conditions for optimal H \(_2\) ${}_2$ production were investigated, including analysis of requisite shock strengths and potential driver gases. The chemical kinetic and gasdynamic analyses presented here reveal a number of challenges associated with the shock wave reforming approach, but simultaneously reveal opportunities for further research and innovation.