循环流化床甲醇制芳烃分离工艺的模拟与改进

Benzene, toluene, and xylene in aromatics are the essential raw materials in the petrochemical industry and can be used to synthesize the quantities of chemical products. In recent years, there have been increasingly demand for aromatics all over the world. Conventionally, benzene, toluene, and xylene are mainly produced from catalytic reforming oils and pyrolysis gasoline. However, China is short of crude oil reserves and has been the largest crude oil importer, which brings great challenge for the aromatics industry. Compared with the crude oil, coal reserves are relatively abundant in China. Therefore, it will be a favorable development direction to take coal as a breakthrough and develop the coal-based aromatics industry with Chinese characteristics, which has recently received great interest on the coal-based methanol to aromatics technologies in China. However, most of existing researches are theoretical and have a certain distance from practical application in industry. The separation process plays an important role in obtaining the qualified aromatics products, but it is energy intensive. Hence, it is necessary to improve the performance of the separation process. Based on the technology of methanol-to-aromatics with circulating fluidized bed reactor, this work establishes a full-flow simulation model for the downstream separation process via the Aspen HYSYS software. Sensitivity analysis is then performed on the amount of absorbent used in the methane absorber, which shows that the amount of absorbent can be reduced by 27.7% with little reduction in methane absorption. This work also achieves the integration of the heat exchanger network of the process such that the hot utility consumption can be reduced by 16.75% and the cold utility consumption is reduced by 11.89%. The proposed method in this work can provide theoretical support, optimization directions and recommendations for the methanol to aromatics process.