Study On Thermal Hazard And Vent Sizing Of Benzaldehyde Oxime

Benzaldehyde oxime is an important intermediate, it’s a colorless and transparent crystal. It’s melting point is about 30-33℃. It’s belong to irritant material, and harmful to eyes, respiratory, skin. It’s used as medical and pesticide intermediate. Under high temperature, benzaldehyde oxime will decomposes and generate N2, NH3, trace of acetic acid and H2O. The product has no harmful effect to pipeline and tank. The decompositon heat of benzaldehyde oxime is high, and the onset temperature is low. Incident may happen due to lose of temperature control. But research on the thermal hazard and vent sizing of benzaldehyde oxime is hard to see.Differential scanning calorimeter and PHI-TECII are employed in this paper to do research on the thermal hazard and vent sizing of benzaldehyde oxime.Firstly, DSC was employed to test benzaldehyde oxime under dynamic condition, and the decomposition mechanism was studied based on the experiment data. Secondly, PHI-TECII was employed to test benzaldehyde oxime under adiabatic condition, the thermal decompositon parameters were calculated base on the data. Self-acceleration decompositon temperature was calculated with a package of 25kg. The data gotten from PHI-TECII test was used to do vent sizing calculation, and correction was done to make the data closer to real conditon. Comparison was done bettwen venting size before correction and after correction. Finally, mathematic model of benzaldehyde oxime storage tank was constructed, to study to temperature and pressure change under venting condition.Results showed that, the decomposition mechanism was different under different heating rates. Accoroding to the specific decomposion heat and SADT, benzaldehyde oxime belongs to self reactive substance. Comparison bettwen three different venting method showed that, bottom discharge controled by temperature needs the smallest venting size, top venting needs the biggest venting size. After correction, the calculated value of top venting size become larger, but the size of bottom discharge become smaller, mathematic model was constructed.