高静态动作压力下粉尘爆炸泄放标准的可靠性

Reliability of Dust Explosion Venting Standards Under Elevated Static Activation Overpressures

粉尘爆炸泄放设计标准的可靠性对能否实现爆炸防护尤为关键.以中径70μm 石松子粉尘为介质,采用20 L 球形粉尘爆炸装置进行了4种泄放口径、静态动作压力在0.12~0.6 MPa 的爆炸泄放实验,对比了实验值与 NFPA 68和 EN 14491计算值.结果表明,NFPA 68在预测高静态动作压力下的泄放面积时,随着泄放口径的增大,预测结果由保守变为危险,但预测结果精度较好且数值稳定；EN 14491在预测高静态动作压力下的泄放面积时非常保守,预测精度较差,数据不可靠.依据两种标准推荐的经验函数关系,分析了NFPA 68和 EN 14491在预测高静态动作压力时产生这种差异的原因.

The reliability of dust explosion venting standards is of great importance to explosion protection.Dust explosion venting experiments with four venting diameters under elevated static activation overpressures ranging from 0.12 to 0.6 MPa were performed in the 20-liter chamber. The lycopodium dusts with a median diameter of 70 μm were adopted.The experimental results were compared with the predictive values calculated by NFPA 68 and EN 14491 .The results indicated that NFPA 68 results tend to be conservative for small venting diameters and dangerous for larger venting diameters.It was found that the prediction results of NFPA 68 correlation have a good accuracy and are stable under elevated static activation overpressures.However,the prediction results of EN 14491 are inaccurate and unstable,which tend to be very conservative. The huge divergence between NFPA 68 and EN 14491 results under elevated static overpressures was analyzed based on the correlations of the empirical functions proposed by the standards.