Synthesis of insoluble sulfur and development of green technology based on Aspen Plus simulation

Abstract

The continuous process for the production of insoluble sulfur (IS) has been developed to overcome the disadvantages associated with the traditional batch process, such as low automation, discontinuous production, and high consumption of sulfur and CS2. The consumption of CS2 in the continuous process is lower than that in the batch process. The recovery of solvent facilitates the recycling of CS2 and N2 in addition to the closed circulation of the entire system. The key process and recovery parameters of the IS synthesis were simulated using Aspen Plus. Sulfur was completely recovered after high-temperature pyrolysis, and the utilization ratio of sulfur atoms was increased from approximately 50% to more than 95%. Tail gas was comprehensively utilized through compression and cryogenic green treatment. Based on the developed green synthesis process and simulated process parameters, the continuous production of IS was evaluated on an industrial scale of 10,000 metric tonnes. Owing to the continuous characteristics of the production process, the air tightness of the production process was significantly improved, and the quality of the product was more stable than that of the product obtained by the current domestic batch process. The unconverted sulfur could be recycled after recovery, without low-grade sulfur as a by-product. The amount of sulfur used as raw material per unit product was reduced; the comprehensive conversion rate of sulfur to IS exceeded 95%, which significantly improved the utilization rate of sulfur atoms. Through the compression and condensation of the tail gas, the recovery efficiency of CS2 was considerably improved at the same temperature, and compressed N2 could be simultaneously obtained. The liquefaction rate of CS2 approached 91.78%, which was characterized by obvious greening.

Keywords

• insoluble sulfur
• aspen plus simulation
• green recycling process
• process research