CFD simulations serve as a bridge between theory and reality. Simulations have the advantage that diagnostic probing of a computer simulation does not disturb the flow and normal operation. It may allow one to switch on and off various interactions included in the model to understand the relative contributions of each individual process, which is extremely difficult if not impossible to achieve in experiments. These simulations allow detailed analyses at an earlier stage in the design cycle, with less cost, with lower risk and in less time than experimental testing.In this work,CFD simulations were performed on sieve tray used in distillation coloumn.High degree of competitiveness associated with petroleum leads to the exhaustive search for new technologies that enable greater efficiency in the related processes.The simulation results are shown that CFD is a powerful tool in tray design, analysis and trouble shooting, and can be considered as a new approach for efficiency calculations.