The present study deals with simulation of agglomeration reactors, based on a CFD calculation method for describing the turbulent flow field, coupled with a direct Monte-Carlo method for the agglomeration process. The potentiality of stochastic methods, well suited for simulation of spherical agglomeration where complex kernels have to take into account the effects of the particles size and of the composition of binding agent, is illustrated. Furthermore, it is shown that the coupling between hydrodynamics and kinetics makes it possible to model very complex processes, and also to scale-up those processes from batch to continuous mode operation. Application and results are presented for the complex case of agglomeration in suspension of an organic pigment, performed in a standard stirred vessel equipped with a pitched blade turbine.