Effect of combination of explosion venting and chemical barrier on starch explosion suppression in a large scale connected vessels

The explosion of starch poses a potential threat to the process safety of food and energy enterprises in product processing and storage. To control explosion, a 5 m3 columnar tank with a 10 m long connecting pipe at one end and a 700 mm diameter explosion vent at the other end was built as an experimental device. Combined controlled explosion experiments were conducted using a rupture disc with a static activation pressure of 10 kPa and a chemical barrier containing ABC powder with nitrogen as the driving gas to investigate the pressure and flame change characteristics inside the vessel and piping. The experimental results show that the maximum explosion pressure in the connected vessel without explosion venting is 41.21kPa and the maximum pressure rise rate is 5.20 bar/s. Explosion venting reduces the maximum explosion pressure and pressure rise rate in the vessel by 52.31 % and 21.92 %, respectively, and reduces the flame propagation speed in the pipeline, so that the chemical barrier device can effectively isolate the flame when the installation distance is more than 6 m. The N2 and ABC dry powder two-phase explosion suppressant produced an effective inhibition effect through the physical effects of oxygen insulation, heat absorption, and thermal transmission weakening, as well as the chemical effect of eliminating explosive radicals. The explosion venting provides an initial defense by releasing any remaining pressure and heat of the explosion, while the chemical barrier provides a secondary layer of protection by extinguishing the flame and suppressing the explosion in the pipe to prevent further damage. This combination can greatly reduce the risk of equipment damage, injuries, and fatalities caused by explosions in industrial settings.