Easurement of solids velocity and concentration in a large cold CFB model

Abstract

This work applies optical probe and particle image velocimetry (PIV) measurements for determining the local characteristics of the solids flow in a CFB riser and discusses benefits and limitations of the two methods. Measurements were carried out in an 8.5 m tall CFB riser with a cross-section of 0.7 m x 0.12 m. The optical probe was used to measure both solids volume fraction and velocity whereas the PIV was limited to solids velocity measurements. In addition, the vertical pressure profile and solids circulation rate were measured by means of pressure transducers. The work demonstrates the challenge of applying detailed solids flow measurements in CFB reactors. Both methods applied are associated with limitations and inaccuracies and it is concluded that a combination of both local measurement methods and the global pressure measurements will improve the interpretation of the solids flow field in CFB risers