This book conveys a basic understanding of chemical reactor and its design methodologies that incorporate both scale-up and hazard analysis. It shows readers how to select the best reactor for a particular chemical reaction, how to estimate its size and how to obtain the best operating condition. The objective of this book is to develop a model for a two batch reactors in series with interchange. A model has been formulated consisting of an ideal reactor to represent a real reactor. First, it has been solved for exit concentration and conversion in terms of two parameters ? and ? which are a function the two adjustable parameters v_b and V_D and then simulate it using matlab software. In the chemical engineering field, models can be useful in all the phases from research and development to plant operation. Model and their simulation are tools utilized by us to analyze the process.