Process model is a useful tool for understanding the behavior of chemical processes. In this chapter, the modeling and simulation of the sorption-enhanced chemical looping reforming and water splitting (SECLR-WS) process are explained. The SECLR-WS process was simulated by using Aspen Plus program. The Aspen Plus is a flowsheeting program based on a sequential modular approach. Basically, the sequential modular is a computational strategy which perform the simulation of the process by following the calculation sequence (unit-by-unit). Details of the flowsheet development for the SECLR-WS process are given in this chapter, including major assumptions, a module of a unit, and stream detail. In addition, the validation of SECLR-WS simulation against with experimental data reported in the literature is presented.