NUMERICAL SIMULATION OF AN ETHYLENE RE-LIQUEFACTION PLANT

Abstract

The present paper is concerned with the numerical simulation of an ethylene re-liquefaction plant. The plant is part of a petrochemical complex, set up in the city of Aratu, state of Bahia, Brazil. The cooling effect is obtained through a two-stage cascade cycle, involving two circuits with different working fluids: ammonia in the high pressure side, and ethylene is the low pressure. The main components of the system include: two-stage double acting reciprocating compressors, shell-and-tube heat exchanger, store and flash tanks and control valves. The simulation model was developed by considering the energy and mass conversion laws, the empirical heat transfer coefficient relations, heat exchanger and compressor theories and the thermophysical properties of the working fluids. The result was a set of nonlinear equations solved by a sequential modular technique. Predicated thermodynamic parameters (temperature, pressure and mass flow rate), at different points of the systems, were compared with the available plant operational data, with food agreement being obtained. A parametric anaylsis of the plant was also carried out. © 1997 John Wiley & Sons, Ltd.