Dynamic modeling and control of the air separation unit in an IGCC power plant

The technology of Integrated Gasification Combined Cycle (IGCC) power plant is one of the most promising energy producing and coal utilization methods. It offers the opportunity to use fossil energy sources as well as satisfy the strict environmental constraints. A typical IGCC power plant mainly consists of an air separation unit, the gasification system, the gas clean-up process, and the combined-cycle unit. This paper closely investigates the dynamic characteristics and control strategy of the air separation unit. The rigorous first principles mathematic model of the cryogenic rectification column, which is the core of the air separation, is firstly developed. Moreover, with several step changes introduced, dynamic simulations are carried out to illustrate the transient behavior of the column. Considering it a multi-input, multi-out and energy intensive system, the control scheme according to the character of the column is presented, and the performance of the control strategy is simulated.