Explosive Characteristics And Explosion Protection Of 7-ACA Dust Within The Dust Collector

A lot of 7-aminocephalosporanic acid(7-ACA)dust leaks from processing and production in pharmaceutical industry,which harms the occupational health of workers and causes environmental pollution.The blasting of drug dust in removal system is able to result in serious casualty and huge economic loss.The present study was performed aiming at the explosive characteristics and explosion protection of 7-ACA dust in dust collectors of the pharmaceutical industry.The explosion parameters of 7-ACA dust were tested.Gas mixing system was designed and installed on the basis of 20 L spherical explosive device to confirm the inerting effect of nitrogen on the 7-ACA dust explosion.The minimum ignition temperature of 7-ACA dust cloud is 458? when the spray pressure is 0.1MPa and the dispersion mass is 0.6g.When the 7-ACA dust layer is12.5mm in thickness,the minimum ignition temperature is 230?.The higher temperature of the hot plate is able to reduce the regenerative time before the dust layer is on fire and accelerating the phenomenon of dust layers smoldering.The lower explosion limit of7-ACA dust is 18.5g/m3.The minimum ignition energy is 12 mJ.Two explosion parameters prove the high explosion sensitivity of 7-ACA dust.The maximum explosion pressure of 7-ACA dust and the maximum rate of pressure rise are 0.82 MPa and55.91MPa/s when the dust concentration is 750g/m3.The design of gas(N2,O2 and air)mixing system was carried out on the basis of 20 L spherical explosive device.The air inlets and gas sources were added to the main body of the device,which regulated the internal oxygen concentration by filling nitrogen and oxygen into the device.When the internal oxygen concentration reduces,the maximum explosion pressure decreases significantly.The limit oxygen concentration is 10.93%.The 7-ACA explosion models in dust collector and related links were summarized.The relief area on dust collector was calculated taking advantage of the experimental results.The nitrogen inerting functioning on a dust collector was technically analyzed and the explosion protection measures were proposed.