Design and optimization of ethylene production utilizing new technologies

The use of new technologies for improving the profitability of the conventional ethylene process was investigated. Several separation schemes utilizing new technologies were developed and optimized for the present ethylene plant.; The hybrid distillation/membrane system utilizing facilitated transport membrane technology was developed and optimized for the separations of ethane from ethylene and propane from propylene. Simulation and optimization of various distillation/membrane hybrid configurations as well as stand-alone membrane cascade systems have been examined under different operating conditions of temperature and pressure. For the ethylene/ethane separation, the reduction in refrigeration requirement is the key to a successful hybrid system and that the Series Configuration Hybrid System (SCHS) is the optimum design for a grass-roots ethylene plant. The optimum separation scheme determined for the propylene/propane separation is the Top-Bottom Configuration Hybrid System (TBCHS).; This study also Investigated the feasibility of separating hydrogen from the cracked gas in an optimal manner before entering the low-temperature section of the ethylene plant. The performance of two new commercial polyimide membranes as well as a new polysulfone membrane was evaluated. This study showed that the two-stage membrane cascade with recycling is the optimum design compared to the conventional scheme.; The heat exchanger networks for the conventional ethylene process and the modified ethylene process were optimized according to pinch technology. A systematic approach for the heat integration of the ethylene process was developed. The optimized heat exchanger networks provide processing savings in both the energy and capital costs. Retrofit of the conventional ethylene process utilizing the new technologies also showed economic advantages.