In this paper the investigation in part 1 for batch acidulation using the shrinking core model is extended to the case of continuous acidulation. Three processes are investigated, namely, the dihydrate, hemihydrate, and foam processes. The effective diffusivities D-e are evaluated and compared with the values obtained from the batch experiments in part 1. The comparison reveals the degree of coating occurring in the three continuous processes investigated and thus points out the suitable techniques for the improvement of the performance of these processes.