Flow characteristics and mixing properties in a high velocity liquid-solid loop reactor

Experiments were performed in a liquid-solid loop reactor with a loop length of 14.45 m and an inner diameter of 90 mm under high velocity conditions. The variations in pressure gradient along the downflow, upflow and bend sections of the loop were investigated respectively. Pressure gradient in the downflow and upflow sections can be predicted with the model developed. The axial phase holdups are uniformly distributed along the loop. The liquid and solids velocities in the reactor are almost the same in the operating range tested. The axial dispersion coefficients of the liquid and solid phases were measured with the tracer injection response method and the dispersion coefficients of the solid and liquid phases are nearly the same. These characteristics make the liquid-solid system behave as a pseudo-homogeneous system and make the high velocity loop reactor easy to scale up. A commonly used correlation for axial dispersion substantially underestimated the axial dispersion coefficients.