Rob
Ansys Employee

DPM data is tracked on the particles, not on the cells (there are some exceptions when you are fully coupled). You may also find pneumatic conveyors to run at a higher volume fraction than DPM is intended for, and the diameter may also be a problem. 

Not sure why you're trying to write out particle data, if you save a .dat.h5 or .dat.gz along with the case it'll post process fine in Fluent. Particle tracks and CFD Post can be a little messy.