Nitrogen and carbon dioxide dilution effect on upper flammability limits for organic compound containing carbon, hydrogen and oxygen atoms

In this work semi-empirical models for predicating upper flammability limit (UFL) for flammable gases diluted with inert nitrogen and with carbon dioxide are developed, respectively. Experimental data for 20 flammable gases are collected and used to determine the unspecified parameter in our earlier theoretical model. It is found that if we divide these 20 organic compounds into three groups—CnHm, CnHmO, and CnHmO2, the coefficients of determination (R2) for these three categories for the case of inert nitrogen will be 0.9969, 0.9940 and 0.9971, respectively; and for the case of inert dioxide will be 0.9922, 0.9811 and 0.9877, respectively. If all the compounds are unified in a same model, it is found the R2 values are 0.9954 and 0.9897 for inert nitrogen and inert carbon dioxide, respectively. Experimental data of cyclopropane, ammonia, benzene, acetylene, carbon disulfide, carbon monoxide, diethyl ether, and hydrogen, which are not included in the original semi-empirical model, is used to validate the predictive ability for the proposed unified model, and it is found that the average predictive errors for each component are lower than 10% for inert gases of both nitrogen and carbon dioxide.