Boilard S.P.,Dalhousie University |
Amyotte P.R.,Dalhousie University |
Khan F.I.,Memorial University of Newfoundland |
Dastidar A.G.,Fauske and Associates |
Eckhoff R.K.,University of Bergen
Journal of Loss Prevention in the Process Industries | Year: 2013
Explosibility of micron- and nano-titanium was determined and compared according to explosion severity and likelihood using standard dust explosion equipment. ASTM methods were followed using a Siwek 20-L explosion chamber, MIKE 3 apparatus and BAM oven. The explosibility parameters investigated for both size ranges of titanium include explosion severity (maximum explosion pressure (Pmax) and size-normalized maximum rate of pressure rise (KSt)) and explosion likelihood (minimum explosible concentration (MEC), minimum ignition energy (MIE) and minimum ignition temperature (MIT)). Titanium particle sizes were -100 mesh (<150 μm), -325 mesh (<45 μm), ≤20 μm, 150 nm, 60-80 nm, and 40-60 nm. The results show a significant increase in explosion severity as the particle size decreases from -100 mesh with an apparent plateau being reached at -325 mesh and ≤20 μm. Micron-size explosion severity could not be compared with that for nano-titanium due to pre-ignition of the nanopowder in the 20-L chamber. The likelihood of an explosion increases significantly as the particle size decreases into the nano range. Nano-titanium is very sensitive and can self-ignite under the appropriate conditions. The explosive properties of the nano-titanium can be suppressed by adding nano-titanium dioxide to the dust mixture. Safety precautions and procedures for the nano-titanium are also discussed. © 2013 Elsevier Ltd.
Kwasny R.,Fauske and Associates
Process Safety Progress | Year: 2012
Drying is an especially hazardous operation. To make this operation safer, it is critical to understand the hazards associated with decomposition, fire, and explosion including worst-case scenarios resulting from operational and control failures. This article describes the tests and standards required to prevent accidents when handling bulk powders and dusts. The outcome of these tests and standards is to quantify the risks for normal and upset conditions and to implement adequate safeguards to prevent accidents. © 2012 American Institute of Chemical Engineers (AIChE).
Brooks C.S.,Purdue University |
Paranjape S.S.,Purdue University |
Ozar B.,Purdue University |
Ozar B.,Fauske and Associates |
And 2 more authors.
International Journal of Heat and Fluid Flow | Year: 2012
In an effort to improve the prediction of void fraction and heat transfer characteristics in two-phase systems, closure relations to the one-dimensional modified two-fluid model are addressed. The drift-flux general expression is extended to two bubble groups in order to describe the void weighted mean gas velocities of spherical/distorted (group-1) bubbles and cap/slug/churn-turbulent (group-2) bubbles. Therefore, correlations for group-1 and group-2 distribution parameters and drift velocities are proposed and evaluated with experimental data. Furthermore, the covariance in the convective flux of the one-dimensional two-fluid model is addressed and interpreted with the available database. The dataset chosen for evaluation of the two-group drift-flux general expression contains 126 total data points taken in an annulus geometry. The proposed distribution parameters show an agreement within ±4.9% and ±1.2% for group-1 and group-2 data, respectively. The overall estimation of group-1 and group-2 void weighted mean gas velocity calculated with the newly proposed two-group drift-flux general expression shows an agreement of ±11.8% and ±17.7%, respectively. © 2012 Elsevier Inc.
Dale D.,Fauske and Associates
Institution of Chemical Engineers Symposium Series | Year: 2012
To demonstrate safe transportation the United Nations guidelines1 define seven classification groups that are determined by performing specific tests. Self-reacting substance should be subject to these testing criteria and classification procedures, and classified into one of the seven types (A-G) which relates their hazard to an allowable quantity/package size for transport. This paper presents an alternative methodology to the prescribed UN testing regime by utilising one easy to perform lOg Advanced Reactive System Screening Tool (ARSST) test to produce the necessary information that allows the packaging classification type to be determined. The UN guidelines allow such alternative procedures to be used provided adequate correlation has been obtained with the classification tests on a representative range of substances and examples of this correlation will be given. © 2012 IChemE.
Theis A.E.,Fauske and Associates
Journal of Loss Prevention in the Process Industries | Year: 2014
A tragic explosion resulting from a runaway chemical reaction occurred at the T2 Laboratories, Inc. facility in December 2007. The U.S. Chemical Safety Board (CSB) completed an incident investigation of the T2 explosion, identifying the root cause as a failure to recognize the runaway reaction hazard associated with the chemical it was producing. Understanding the consequences of process upset conditions is critical to determine risk. This paper will focus on lessons learned from this incident including a comprehensive hazard assessment for reactive chemicals as well as proper collection and application of adiabatic calorimetry data to characterize the chemical reaction and determine appropriate mitigation strategies. Examples will be provided to establish safer operating conditions, implement safeguards and reduce the overall risk. © 2014 Elsevier Ltd.