The paper deals with a new tool for discrete system simulation called QS_PN_Simulation. This tool allows easy creating of queuing system models as Petri net graphs. Simulation experiments with models can be done and chosen statistic results of simulations can be obtained. The use of this system is demonstrated in the paper: creation of a model of chemical production system, simulation experiments with this model and obtained results are presented here. Supposed extension of proposed tool is then discussed in the conclusion of the paper.