(91g) Start up Planning & Support Following a Plant Revamp

Replacement of the 3 major compressors, multiple tower re-trays and addition of a Demethanizer Pre-Stripper changed plant behavior for plant start up. Relying solely on operator's experience and knowledge of the pre-turnaround plant configuration could affect resolution of the numerous abnormal conditions that arise during the start up sequence of any revamped plant. To alleviate this problem, steady state simulation of each of the start up steps was performed in order to provide process targets. The simulations were also converted into monitoring tools integrated with live plant data acquisition. Distillation tray operating windows, compressor curves and data from other relevant process equipment were obtained from vendors and integrated within the simulation and plant data acquisition interface. Operating conditions were then periodically evaluated and direction given to ensure that equipment was being operated within its design envelope. This paper describes the key design changes affecting the process behavior and how process simulation has been used to provide direction to Operations during the execution of the start up.