(34b) Use of Dynamic Simulation in the Design of Ethylene Plants

An ethylene plant experiences startup, shutdown, restart, feed variation and other non-steady state operations over its life cycle. Proper design and protection of process equipment units during these operations are key to the safe and sustained operation of the entire facility. Dynamic simulation is routinely used to determine plant conditions during such transients and ensure that equipment design has covered the entire range of operation. This article reviews some of the relevant application areas of dynamic simulation, and discusses several case studies based on past projects. The case studies cover several critical equipment units relevant to ethylene plants, including compressors, steam turbine/motor drivers and furnace. One example shows how dynamic simulation was used to evaluate the operation of process gas and refrigerant compressors and the steam turbine/motor drivers. Other examples show how dynamic simulation was used in the validation of steam letdown philosophy and evaluation of furnace control.