Integrating reliability optimization formulation into a existing framework will lead to one integrated design, reliability and maintenance optimization framework which in some cases could be computationally expensive. In this work, a decomposition strategy is adopted to decompose the large synthesis, reliability and maintenance optimization problem into manageable sub-problems: reliability optimization and process synthesis, and maintenance and design optimization problems, see Figure 3.1. In chapters 5 and 6, we focus on the development of an integrated design, reliability and maintenance optimization framework.