Computational Fluid Dynamics–Discrete Element Method Simulation of Gas–Solid Flow and Granular Temperature for Biomass Particles: Effects of Particle Properties and Gas Flow Velocity

Biomass gasification is a key pathway for biomass energy conversion, with particle flow characteristics significantly influencing the gasification process. This study uses the computational fluid dynamics–discrete element method to simulate the gas–solid flow of cotton stalk, corn stalk, and salix particles in the riser, investigating the effects of particle properties and gas flow velocity on particle distribution, gas-phase pressure, and granular temperature. Results show that cotton stalk particles, due to their higher density, take longer to stabilize and have a higher mass fraction, while corn stalk particles, with lower density, stabilize more quickly but have a lower mass fraction, potentially affecting gasification efficiency. At the same gas velocity, the cotton stalk system has the largest pressure drop and a lower granular temperature, indicating stable flow, while the corn stalk system shows the lowest pressure drop and a higher granular temperature, indicating more intense particle motion. As gas velocity increases, pressure drop decreases, particle mass fraction decreases, and particle motion intensifies. Higher density particles should be used with higher gas velocities, while lower density particles should be used with lower gas velocities. A dimensionless granular temperature prediction model that achieves less than 20% error is developed. These results provide theoretical support for raw material selection and gas flow parameter regulation in biomass gasification.