Self-ignition of dust at reduced volume fractions of ambient oxygen

  • Experiments were performed to investigate the self-ignition behaviour of accumulations of four different technical dusts at oxygen volume fractions ranging from 1.3 to 21%. For this purpose a laboratory oven used for hot storage testing was modified to allow flushing with the pre-mixed oxygen/nitrogen mixture of the desired composition. It was found that for all sample volumes investigated the self-ignition temperatures were higher the lower was the oxygen volume fraction. In addition, the type of reaction changed obviously, since the apparent activation energy significantly decreased at oxygen volume fractions below 6%. However, it was still possible to observe exothermic effects at oxygen volume fractions as low as 1.3%. A numerical model was established to simulate the process of self-ignition including the coupled heat and mass transfer within the dust accumulation using a finite element solver. The model consists of six balance equations for the heat transfer and the transport ofExperiments were performed to investigate the self-ignition behaviour of accumulations of four different technical dusts at oxygen volume fractions ranging from 1.3 to 21%. For this purpose a laboratory oven used for hot storage testing was modified to allow flushing with the pre-mixed oxygen/nitrogen mixture of the desired composition. It was found that for all sample volumes investigated the self-ignition temperatures were higher the lower was the oxygen volume fraction. In addition, the type of reaction changed obviously, since the apparent activation energy significantly decreased at oxygen volume fractions below 6%. However, it was still possible to observe exothermic effects at oxygen volume fractions as low as 1.3%. A numerical model was established to simulate the process of self-ignition including the coupled heat and mass transfer within the dust accumulation using a finite element solver. The model consists of six balance equations for the heat transfer and the transport of five chemical species. It shows that the model reflects self-ignition in dust accumulations with satisfying accuracy, as long as the input data generated by preceding experiments are reliable.zeige mehrzeige weniger

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Metadaten
Autor*innen:Martin Schmidt, Christian Lohrer, Ulrich Krause
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Journal of loss prevention in the process industries
Jahr der Erstveröffentlichung:2003
Verlag:Butterworth
Verlagsort:Guildford, Surrey
Jahrgang/Band:16
Erste Seite:141
Letzte Seite:147
Freie Schlagwörter:Dust; Numerical modelling; Self-ignition; Self-ignition temperatures
DOI:10.1016/S0950-4230(02)00095-5
ISSN:0950-4230
ISSN:1873-3352
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Bibliotheksstandort:ZJ 79
Datum der Freischaltung:19.02.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:20.01.2005
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