Safe-Parkingof a Hydrogen Production Unit.

Thiswork considers the problem of handling the failure of purificationequipment in a hydrogen production process. In this process, naturalgas and superheated steam are fed to a heated chemical reactor termeda reformer to produce hydrogen. The effluent gas is further processedand finally purified in a pressure swing adsorber (PSA). The off-gasout of the PSA is used to provide heat to the reformer. The failureof the PSA results in the loss of the off-gas, precluding the possibilityof the continuation of nominal operation. If not properly handled,this fault can lead to a shutdown of the entire plant. To achievestable operation while meeting operating requirements, a model predictivecontrol (MPC) based safe-parking framework is designed for the handlingof the fault. The key idea is to drive the process to a feasible operatingpoint that enables stable operation in the faulty mode. MPC is usedto handle the multivariable nature of the process and operating constraints.It also guides the process to a different operating region while meetingoperating requirements. The effectiveness of the safe-parking designis demonstrated through simulations using a first-principles modelof the hydrogen production unit. [ABSTRACT FROM AUTHOR]