Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
583412 | Journal of Hazardous Materials | 2008 | 9 Pages |
Abstract
Burning velocity measurements of nitrogen-containing compounds, i.e., ammonia (NH3), methylamine (CH3NH2), ethylamine (C2H5NH2), and propylamine (C3H7NH2), were carried out to assess the flammability of potential natural refrigerants. The spherical-vessel (SV) method was used to measure the burning velocity over a wide range of sample and air concentrations. In addition, flame propagation was directly observed by the schlieren photography method, which showed that the spherical flame model was applicable to flames with a burning velocity higher than approximately 5 cm sâ1. For CH3NH2, the nozzle burner method was also used to confirm the validity of the results obtained by closed vessel methods. We obtained maximum burning velocities (Su0,max) of 7.2, 24.7, 26.9, and 28.3 cm sâ1 for NH3, CH3NH2, C2H5NH2, and C3H7NH2, respectively. It was noted that the burning velocities of NH3 and CH3NH2 were as high as those of the typical hydrofluorocarbon refrigerants difluoromethane (HFC-32, Su0,max = 6.7 cm sâ1) and 1,1-difluoroethane (HFC-152a, Su0,max = 23.6 cm sâ1), respectively. The burning velocities were compared with those of the parent alkanes, and it was found that introducing an NH2 group into hydrocarbon molecules decreases their burning velocity.
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Authors
Kenji Takizawa, Akifumi Takahashi, Kazuaki Tokuhashi, Shigeo Kondo, Akira Sekiya,