**Simulation and Optimization of Multi-period Steam Cracking Process**

Lei Zhang, Hangzhou Wang, Tong Qiu and Bingzhen Chen

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/60558

### **Abstract**

Hydrocarbon steam cracking is the most important process for producing industrial chemicals such as olefin and aromatics. Steam cracking modelling and optimization is an effective way for increasing production and saving energy. In this chapter, multiscale modelling and elementary reaction networks are established and used in the modelling and optimization of steam cracking. However, the large scale of the optimization model makes it difficult to obtain a solution. Thus, a surrogate coke thickness model for long-term steam cracking is proposed in this chapter to remove the connection between different periods of steam cracking process. By so doing, a parallel simulation can be used to accelerate optimization. An industrial case study showed optimization time to be significantly reduced from 17.78 hours to 2.08 hours using multi-period optimization with parallel simulation and the surrogate coke thickness model. It has been shown that a 0.62% increase in ethylene yield can be obtained via operating condition optimization, which demonstrates the effectiveness of the multi-scale steam cracking model and multi-period optimization with parallel simulation.

**Keywords:** Steam cracking, multi-scale modelling, elementary reaction network, parallel simulation, surrogate model
