Jan16_Laminar_Burning_Velocity_Testing.jpg

Combustion Properties

Laminar Burning Velocity Testing

BakerRisk has the capability to make Laminar Burning Velocity (LBV) measurements. The LBV is a fundamental physical property of a fuel/oxidizer mixture and is used in the Baker-Strehlow-Tang (BST) blast model to classify the fuel of interest as low, medium, or high reactivity. In the BST model, the reactivity of a fuel in part determines the severity of a Vapor Cloud Explosion (VCE). For many common fuels, the LBV has already been measured and is readily available in published literature. However, the LBV has not been measured for many fuel-mixtures commonly found in chemical plants (i.e., highly diluted fuel streams, multi-component fuel mixtures). It is possible to estimate the LBV of a fuel or fuel mixture using published correlations, (i.e., Britton Correlation, Le Chatelier’s Rule) but these correlations are limited in application. A LBV test is needed if the fuel or fuel-mixture of interest has not been studied before or if the results of a correlation place the fuel near the border between two reactivity ratings. Without further investigation, the fuel would typically be assigned to the higher reactivity classification to ensure conservatism, resulting in higher facility costs due to explosion prevention or mitigation measures that may not be necessary. An LBV test will classify the fuel correctly and ensure that appropriate explosion mitigation measures are employed.

The LBV test apparatus is located at the BakerRisk laboratory. The measurements are performed in a constant-volume test vessel, using the pressure rise as a function of time to calculate the LBV. Measurements can be performed at initial temperatures ranging from 20 – 100° C and at an initial pressure of 1 atmosphere. The measured maximum LBV values from this test apparatus are within ± 5% of published literature values for fuel-air mixtures of methane, propane, n-hexane, iso-octane, ethylene, and hydrogen.