Research On Integrated Optimal Scheduling Of Energy And Production System For Ethylene Plant

Nowadays, with the increasingly fierce competition among enterprises and increasing energy costs, petrochemical companies increasingly focus on energy efficiency. In the past, we tend to study steam system optimization scheduling model from the view of an economic point. We often put forward optimal scheduling model from the view of only their consumption or economic point, Petrochemical production equipment includes not only production systems but also energy systems, and there is a strong coupling between production systems and energy systems, coupling both on material flow and energy flow. In the past, due to the limited size of the models and the computing power, optimization of production scheduling system and energy systems are separate, making it impossible to obtain optimization of the entire plant, and sometimes it has no feasible solution. To get the global optimization scheduling scheme, it is necessary to carry out joint research from the integration perspective of production scheduling system and energy system.The main research contents and innovations are as follows:(1) This paper analyzes the composition of steam power system in ethylene plant, a sub-model of critical equipment and systems for material balance steam power system are established based on the scheduling modeling method of discrete-time expression. A mixed ethylene plant steam power system multi-period Mixed Integer Nonlinear Programming (MINLP) scheduling model is established based on exergy analysis from the energy efficiency point of view. The exergy efficiency is maximized to optimize the scheduling calculation with the actual data from a e ethylene plant and the results are analyzed.(2) The ethylene plant production system is studied on the basis of the optimal scheduling on steam power system. A linear model of cracking furnace yields, fuel consumption model, the occurrence model UHP steam turbine power consumption of the three machines model and separation process model are established. The establishment of a balanced energy production systems and steam power coupling system and mass balance model are established for the coupling relationship existed between the production systems and steam power systems in ethylene plant. By integrating with the constraint equations for steam power systems, a MINLP optimization scheduling model was established to minimize ethylene production cost. An actual ethylene plant case is solved with this model to optimize the scheduling, and the results and analysis are given.(3) We introduce the concept of feasible region division based ’mode’to Convex Region Surrogate (CRS) model based on actual operating data from an ethylene plant. A model based on the modeling of MINLP optimization scheduling and’mode’ is established. Compared with the integrated optimization scheduling model in the previous section, this model can get a more realistic scheduling policy.