Numerical Simulation Study on the Effects of Nozzle Deflection Angle and Nozzle Inclination Angle on Cold-State Gas–Solid Flow Characteristics in an EPCG

To investigate the non-uniform gas–solid flow and insufficient particle residence time in an Ende pressurized pulverized-coal gasifier (EPCG), a three-dimensional cold-state numerical model of a 45,000 Nm3/h industrial-scale gasifier was established to study the effects of nozzle deflection angles (30–50°) and nozzle inclination angles (15–23°) on gas–solid flow characteristics. (1) Considering the difficulty of directly measuring particle flow behavior inside a pressurized gasifier, industrial-scale cold-state simulations were conducted to analyze particle transport and flow evolution under different nozzle structures; (2) flow uniformity and stability were comprehensively evaluated using axial velocity, particle volume fraction, residence time, and radial symmetry, and the different effects of nozzle deflection angle and nozzle inclination angle were comparatively analyzed. The results show that a typical wall-attached upward flow and central recirculation structure is formed in the bed, with particles exhibiting spiral upward transport. Flow uniformity gradually improves with increasing bed height. Increasing the nozzle deflection angle mainly enhances particle transport, whereas the nozzle inclination angle has a more significant effect on flow symmetry and stability. Nozzle inclination angles of 19–21° and nozzle deflection angles of 40–45° are more favorable for stable flow formation, while the 40°/19° configuration gives the best flow uniformity and stability.