It´s seems to be that the viscosity ratio exceeds in every cell (800k) + it shows "reversed flow pressure outlet ". 

I am following this tutorial 1:1 and just change my parameters.

Basically I am creating a secondary "fluid" (plastic with its density, I don´t change the viscosity), adjust the secondary phase with "Granular", add the diameter and use syamlal-obrien for granular viscosity. After initializing I use the function "Refine/Coarse" and mark the cells where the plastic pellets should be. Than I patch the marked cells with volume fraction of plastic pellets, change my interaction phase with drag coefficient syamlal-obrien-para and then I start to simulate.