Abstract:

The explosive hybrid mixtures formed by the coexistence of flammable gas and dust are widely present in industrial production, and the explosion accidents caused by them have become one of the main forms of explosion accidents. In order to prevent and control the explosion disasters of hybrid mixtures, focusing on LEL of hybrid mixtures as the key characteristic parameter, the research status on the change characteristic of LEL of hybrid mixtures was classified and expounded from the perspective of influencing factors such as flammable gas and dust concentration, chemical reactivity of flammable gas, dust particle size, dust pyrolysis characteristics and dust composition, and the limitations of existing research were summarized. At the same time, in response to the quantitative requirements for LEL of hybrid mixtures, the research status of the quantitative model of LEL of hybrid mixtures was summarized and analyzed from two aspects of experience/semi-empirical model and theoretical model, and the types, characteristics and limitations of existing models were sorted out. Based on these, the research prospects for the change characteristic and the quantitative model of the LEL of hybrid mixtures were proposed. The results indicate that the flammable gas and dust concentration have a direct regulatory effect on LEL. The chemical reactivity of flammable gas, dust particle size, composition, and pyrolysis characteristics are also key influencing factors. Although empirical/semi-empirical models are simple in form and convenient for calculations, they are highly dependent on specific experimental data and conditions, while theoretical models have a more solid scientific foundation, they are often based on idealized assumptions.

Key words: hybrid mixtures, lower explosion limit(LEL), change characteristic, quantitative model, empirical/semi-empirical model, theoretical model