Dynamic Simulation Of Ammonia Decomposition System For PEMFCs

In recent years, green house effect has great impact on our environment. To save energy and increase the efficiency is an inevitable trend. In this thesis, ammonia is used as the raw material to gain H2. This process contains zero carbon. Hydrogen is used to produce power in PEMFCs for small cars. The main models in this process include ammonia decomposition, hydrogen burning, heat exchanger, separation, adsorption and PEMFCs. First, equations of each model are established. According to the equations and real conditions, the best operation parameters are confirmed. Then four kinds of different system processes are established according to the order of each model and the way heat exchangers connected with. The heat usage ratio and energy efficiency in the whole process are reviewed. Combining with the efficiency ratio and economic value, the best system process is confirmed and energy loss in this process is analyzed. After finishing the steady simulation, dynamic simulation in the best process is also calculated. In order to simulate the condition of the start time of cars and the speed-up and speed-down operation, inlet ammonia mole flow rate is changed in the first 300 seconds. The purpose of dynamic simulation is to review the steady performance at the start time and the sensitivity in changing load. The results show that the whole system is steady after 180s, and the steady system has a quick response in changing load.