Cyclic Scheduling of No Backup Cracking Furnace System Considering Real World Operational Characters

Ethylene cracking furnace system is the heart of ethylene production. It can process different raw materials in the pipe group of each furnace and can produce the main chemical products like ethylene, propylene and ethane. In the real world ethylene plant, there are two operation modes in the furnace system, one has a backup furnace in the system and the other is with all the furnaces available online. Compared with the mode which has a backup furnace, the operation mode with all the furnace online has more benefits in prolonging the batch processing time and saving the operational cost. Considering some of the operational characteristics like shutting down for decoking and varying running capacity with the processing cost and product values, the scheduling scheme is optimized to achieve the best economic performance of the cracking furnace system. In this paper, an improved MINLP model considering some real world operational characteristics under the no backup furnace operation mode is developed and solved by a new heuristic iterative solving method. The feasibility and the efficiency of the model is demonstrated through a numerical case study from a real world plant.