Dynamic optimal control of coal chemical looping gasification based on process modeling and complex risk computation

Abstract

The safe and steady running of coal chemical looping gasification system (CCLGS) is directly related to the whole production benefit. CCLGS is composed of dryer, pyrolyzer, decomposer, fuel reactor (FR), and air reactor (AR), which reflects the complexity of the entire production process. In this paper, a novel dynamic safety control strategy based on process modeling and complex risk computation is put forward to ensure the stable operation of CCLGS. First, the process modeling of CCLGS is carried out by Aspen Plus, and the obtained simulation results are in agreement with experimental results. Then, the CCLGS complex network is formed by constructing the adjacency matrix and calculating comprehensive indicator (Ci) value to evaluate the importance of the variables and support risk computation. Subsequently, the risk values of five units are computed based on the unit maximum material coefficient (UMMC), unit general risk coefficient (UGRC), and unit special risk coefficient (USRC). The results prove that FR and AR have higher risk grades than other units. Finally, dynamic control study for FR and AR processes is conducted with the aim of evaluating pressure controllers by safety integrity level. The research will provide beneficial approaches for the safety control of actual plant.