The paper deals with results of the numerical experiment conducted to study the kinetics of the aggregation process occurring in a dispersed system flowing through a tubular reactor. The model is based on the discrete-event simulation paradigm (DES). Previously, a lattice model was used to simulate the process of aggregation of a dispersed system in a periodic reactor. The main result of the given work is the development of a lattice aggregation model applicable to a flow reactor. For creating the model the mathematical apparatus of a random walk on mathematical lattices has been used. As shown in the work, this approach allows removing the problem linked to accounting the effect of many-particles collisions, and as a result it gives the way for describing both a diffusion-limited aggregation and the competition of different kinetic mechanisms taking place on different characteristic times. In this paper, the algorithm that allows taking into account the impact of fresh flow with a dispersed phase entering the flow reactor in the working volume of which aggregation takes place on the kinetic parameters of the process has been submitted.