Study on Slurry Transportation in Riser for Seafloor Massive Sulfides

In recent years, seafloor massive sulfides have been attracting attention as new mineral resources. This paper describes estimation analysis of pressure loss in riser lifting of seafloor massive sulfides (SMS), required for design of pumps and riser. The authors assume a commercial scale and carried out circulating transfer experiment with different concentrations, etc. of the mixed slurry containing the maximum 50mm particle size of a non-spherical. In addition to gravel stone as solid particles in the experiment, the crushed SMS were used. Pressure loss of the vertical riser can be expressed as the sum of the pipe friction and the additional weight increase due to the existence of particles based on the volumetric concentration of solids indicated by previous research, which constructed the estimation formula of practical pressure loss from analysis by modification Froude number and the additional pressure loss coefficient. Also, it was confirmed that pressure loss estimation by numerical simulation of CFDEM using improved analytical model indicates nearly the same in comparison with constructed estimation formula. Through these results it is possible to estimate the pressure loss required for lifting operation for the design of the pumps and riser.