Potentially explosive atmospheres. Explosion prevention and protection. Determination of minimum ignition energy of dust/air mixtures

2021 ◽  
Vol 342 ◽  
pp. 04004
Author(s):  
Cătălin Mihai Popa ◽  
Silviu Marin Nan ◽  
Mihaela Părăian ◽  
Adrian Jurca ◽  
Florin Păun

During the technological processes of processing, production, handling and storage of combustible dusts, complex explosive mixtures may occur, the characteristics of which, in most cases, cannot be assimilated with the existing data in the specialized literature. If these combustible dusts are mixed with air in appropriate proportions and are initiated by an efficient source of ignition, they can burn rapidly and with considerable explosive force. One of the most common sources of ignition of potentially explosive atmospheres generated by the dust / air mixture is static electricity, materialized by electrostatic discharges. In order to assess the risk of ignition of an explosive mixture of air / dust, it is necessary to know the sensitivity of the explosive atmosphere to ignition, ie the value of the minimum ignition energy of the explosive mixture, which is then compared with the energy resulting from an electrostatic discharge. The paper presents a comparative analysis regarding the methods of determining the minimum ignition energy for air / fuel dust mixtures, using different devices, on the same type of dust.


Author(s):  
Petr Lepik ◽  
Dieter Gabel ◽  
Wojciech Adamus ◽  
Ladislav Mokos ◽  
Miroslav Mynarz ◽  
...  

Abstract This article focuses on determination of the minimum ignition energy of dust. For the measurement of the minimum ignition energy of dust are available device from different manufacturers. In this article, the comparison device from three manufacturers - Chilworth, Kühner and Anko are executed. For the experimental measurement of the minimum minimum ignition energy was chosen 5 dust samples so that they are represented sample of organic dust, synthetic organic dust and coal dust. The article briefly introduces each apparatus for determining the minimum ignition energy and there is a comparison of the results obtained with individual devices. Finally, it is an assessment the results obtained and used test equipment.


2013 ◽  
Vol 26 (6) ◽  
pp. 1655-1660 ◽  
Author(s):  
Angelika Wähner ◽  
Gisbert Gramse ◽  
Tim Langer ◽  
Michael Beyer

A model is proposed for the ignition of quiescent multidroplet fuel mists which assumes that chemical reaction rates are infinitely fast, and that the sole criterion for successful ignition is the generation, by the spark, of an adequate concentration of fuel vapour in the ignition zone. From analysis of the relevant heat transfer and evaporation processes involved, ex­pressions are derived for the prediction of quenching distance and minimum ignition energy. Support for the model is demonstrated by a close level of agreement between theoretical predictions of minimum ignition energy and the corresponding experimental values obtained using a specially designed ignition apparatus in which ignition energies are measured for several different fuels, over wide ranges of pressure, mixture composition and mean drop size. The results show that both quenching distance and mini­mum ignition energy are strongly dependent on droplet size, and are also dependent, but to a lesser extent, on air density, equivalence ratio and fuel volatility. An expression is derived to indicate the range of drop sizes over which the proposed model is valid.


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