Emergency relief system design for high-viscosity two-phase flow: an analysis of butene-1 polymerization runaway system

The rational design of emergency relief systems for butene-1 polymerization processes is significantly complicated by the high viscosity characteristic of these systems. This study systematically investigates the runaway reaction dynamics and relief characteristics associated with butene-1 polymerization. The findings indicate that the pressure relief associated with the polymerization runaway of butene-1 is characteristic of a high-viscosity, two-phase flow vapor system. Based on the results of closed-cell tests, the venting sizing is determined for the pressure release of butene-1 polymerization plant that produces 50,000 tons annually. However, detailed relief simulation studies reveal that the release phase of butene-1 polymerization systems encounters challenges due to polymer precipitation. This precipitation can lead to blockages within the discharge line, consequently reducing the system`s release capacity. Our analysis demonstrates that maintaining pressure buffering during the relief phase facilitates the flash vaporization of butene-1 monomer within the reactor, significantly mitigating polymer discharge. To address the issues arising from polymer precipitation, we strongly recommend the implementation of a dual-valve control mechanism, comprising a rupture disc and a safety valve, alongside a reduction in the discharge pipeline length. The outcome of this research provides a dependable solution for the rational design of emergency relief systems tailored to high-viscosity polymerization systems, specifically addressing the challenges posed by polymer precipitation that can obstruct discharge pipelines.