Brigham Young University BYU ScholarsArchive Theses and Dissertations 2010-06-25 Flammability Limits, Flash Points, and Their Consanguinity: Critical Analysis, Experimental Exploration, and Prediction Jeffrey R. Rowley Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Chemical Engineering Commons BYU ScholarsArchive Citation Rowley, Jeffrey R., "Flammability Limits, Flash Points, and Their Consanguinity: Critical Analysis, Experimental Exploration, and Prediction" (2010). Theses and Dissertations. 2233. https://scholarsarchive.byu.edu/etd/2233 This Dissertation is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Flammability Limits, Flash Points, and their Consanguinity: Critical Analysis, Experimental Exploration, and Prediction Jef Rowley A dissertation submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Doctor of Philosophy W. Vincent Wilding, Chair Richard L. Rowley Larry L. Baxter Thomas A. Knotts David O. Lignell Department of Chemical Engineering Brigham Young University August 2010 Copyright © 2010 Jef Rowley All Rights Reserved ABSTRACT Flammability Limits, Flash Points, and their Consanguinity: Critical Analysis, Experimental Exploration, and Prediction Jef Rowley Department of Chemical Engineering Doctor of Philosophy Accurate flash point and flammability limit data are needed to design safe chemical processes. Unfortunately, improper data storage and reporting policies that disregard the temperature dependence of the flammability limit and the fundamental relationship between the flash point and the lower flammability limit have resulted in compilations filled with erroneous values. To establish a database of consistent flammability data, critical analysis of reported data, experimental investigation of the temperature dependence of the lower flammability limit, and theoretical and empirical exploration of the relationship between flash points and temperature limits are undertaken. Lower flammability limit measurements in a 12-L ASHRAE style apparatus were performed at temperatures between 300 K and 500 K. Analysis of these measurements showed that the adiabatic flame temperature at the lower flammability limit is not constant as previously thought, rather decreases with increasing temperature. Consequently the well-known modified Burgess-Wheeler law underestimates the effect of initial temperature on the lower flammability limit. Flash point and lower temperature limit measurements indicate that the flash point is greater than the lower temperature limit, the difference increasing with increasing lower temperature limit. Flash point values determined in a Pensky-Martens apparatus typically exceed values determined using a small-scale apparatus above 350 K. Data stored in the DIPPR® 801 database and more than 3600 points found in the literature were critically reviewed and the most probable value recommended, creating a database of consistent flammability data. This dataset was then used to develop a method of estimating the lower flammability limit, including dependence on initial temperature, and the upper flammability limit. Three methods of estimating the flash point, with one based entirely on structural contributions, were also developed. The proposed lower flammability limit and flash point methods appear to predict close to, if not within, experimental error. Keywords: flammability limit, flash point, DIPPR, flame propagation TABLE OF CONTENTS Chapter 1. Introduction ............................................................................................................. 1 Chapter 2. Flammability Limits ............................................................................................... 3 2.1 Experimental Determination ........................................................................................... 3 2.1.1 Bureau of Mines Tube Method ................................................................................... 3 2.1.2 ASHRAE Method ....................................................................................................... 4 2.1.3 EN 1839 Tube Method ................................................................................................ 5 2.1.4 Differences in Measurement Methods ........................................................................ 5 2.2 Temperature Dependence of the Flammability Limit ..................................................... 6 2.3 Flammability Limit Estimation Methods ........................................................................ 8 2.3.1 Chemical Equilibrium Methods .................................................................................. 8 2.3.2 Empirical Correlations .............................................................................................. 10 Chapter 3. Temperature Limits and Flash Points ................................................................ 15 3.1 Flammability Temperature Limits ................................................................................ 15 3.1.1 Flammability Temperature Limits: Experimental Determination ............................ 15 3.1.2 Flammability Temperature Limits: Estimation ......................................................... 16 3.2 Flash Point .................................................................................................................... 16 3.2.1 Flash Point: Experimental Determination ................................................................. 16 3.2.2 Flash Point: Estimation ............................................................................................. 18 3.3 Interrelation of Fire-Hazard Properties ......................................................................... 21 Chapter 4. Experimental Method ........................................................................................... 25 4.1 Selection of Measurement Compounds ........................................................................ 25 4.2 Lower Flammability Limit ............................................................................................ 26 4.3 Lower Temperature Limit ............................................................................................. 29 i 4.4 Flash Point .................................................................................................................... 30 4.4.1 Pensky-Martens Procedure ....................................................................................... 30 4.4.2 Small-Scale Procedure .............................................................................................. 30 4.4.3 Additional Measurements ......................................................................................... 31 Chapter 5. Experimental Results ............................................................................................ 32 5.1 Lower Flammability Limit as a Function of Temperature ........................................... 32 5.1.1 Experimental Data .................................................................................................... 32 5.1.2 Adiabatic Flame Temperature Analysis .................................................................... 34 5.1.3 Flame Temperatures and the Theory of Flammability Limits .................................. 38 5.1.4 Comparison with Reported Data ............................................................................... 43 5.2 Lower Temperature Limit and Flash Point ................................................................... 48 5.2.1 Calculated vs. Experimental Lower Temperature Limit ........................................... 48 5.2.2 Flash Point ................................................................................................................ 51 5.2.3 Effect of Measurement Parameters on the Flash Point ............................................. 55 5.2.4 Flash Point vs. Lower Temperature Limit ................................................................ 57 5.2.5 Interrelationship of Flash Point and Lower Flammability Limit .............................. 60 Chapter 6. Critical Review of Previously Reported Data .................................................... 62 6.1 Flammability Data Compilations .................................................................................. 62 6.2 DIPPR® 801 Database .................................................................................................. 65 6.3 Review Methodology .................................................................................................... 66 6.3.1 Measurement Method ............................................................................................... 67 6.3.2 Interrelation of Properties ......................................................................................... 68 6.3.3 Chemical Series Trends ............................................................................................ 71 6.3.4 Example Data Evaluations ........................................................................................ 74 6.3.5 Special Considerations .............................................................................................. 78 ii 6.4 Database Statistics .......................................................................................................