A complete model of particle impact degradation during dilute-phase pneumatic conveying is developed, which combines a degradation model, based on the experimental determination of breakage matrices, and a physical model of solids and gas flow in the pipeline. The solids flow in a straight pipe element is represented by a model consisting of two zones: a strand-type flow zone immediately downstream of a bend, followed by a fully suspended flow region after dispersion of the strand. The breakage matrices constructed from data on 90degrees angle single-impact tests are shown to give a good representation of the degradation occurring in a pipe bend of 90degrees angle. Numerical results are presented for degradation of granulated sugar in a large scale pneumatic conveyor.