A Study of Autoignition Temperature for Alcohols and Ketones

• Main Authors: Yen-Cheng Hsieh, 謝硯丞
• Other Authors: 廖宏章
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/43627602323658820253

碩士 === 中國醫藥大學 === 職業安全衛生學系碩士班 === 98 === Abstract The principal application of autoignition temperature (AIT) is to define the maximum acceptable surface temperature in a particular area, usually for electrical classification purpose. Although AITs of flammable liquids are indispensable information to handle them safely, the reported AITs of flammable liquids in different data compilations are, however, very much diverse. The purpose of this study includes: (1) assess quantitatively the root causes of the uncertainty in measuring AIT; (2) measure the AIT data of alcohols and ketones via the ASTM E659 method; (3) explore the relations between ignition time delay and AIT. The effects of flask material, ambient temperature and ambient humidity on the measured AIT are explored via an L9 orthogonal array. It is found that ambient humidity does not affect the measured AIT of ethanol, but both flask material and ambient temperature are significant factors in measuring AIT of ethanol. It is also found none of the reviewed data compilations reports the AITs conforms to the one obtained by ASTM E659 method in all testing chemicals. Because the AIT obtained by ASTM E659 test method are directly cited by NFPA 70, 497 and 921 codes, the user must be careful in using the AIT reported in the reviewed compilations. The following relation between ignition time delay are theoretically derived and then validated by experiments: ln(tdelay) = E/(R TAIT ) + Constant. The regression analysis for the experimental data shows that the coefficients of determination (R2) range from 0.71 to 0.96 for all test liquid chemicals except for Ethyl Butyl Ketone(R2=0.2703) and Dipropyl Ketone(R2=0.6057). The ignition time delays of these two liquids are very short, and this made the experiment error in measuring time to ignite drastically increases.