(70a) Dust Flame Propagation in Industrial Scale Piping - Part 1: Empirical Study in a Conveying Vessel-Pipeline System

Dust Flame Propagation in Industrial Scale Piping - Part 1: Empirical Study in a Conveying Vessel-Pipeline System

Thomas M. Farrell¹, Jim Vingerhoets², Jef Snoeys², John Going¹

¹ Fike Corporation, 704 SW 10th Street, Blue Springs, MO 64015, USA

² Fike Europe, Toekomstlaan 52, BE-2200 Herentals, Belgium

The use of pipes to connect vessels and transport hazardous materials, such as flammable gases or dusts, is a common practice in the process industry. The potential of fires and explosions has been recognized for decades and is addressed in standards NFPA 68 [1] and NFPA 69 [2]. The purposes of this paper are to present experimental evidence and to further develop a detailed understanding of combustion propagation in industrial scale piping. The experimental evidence on dust flame propagation is scarce, and specific attention was given to expand the knowledge in this field.

Earlier work [3] studying flame propagation in industrial scale piping focused primarily on the propagation of gaseous flames (propane, ethylene, hydrogen) and conditions for deflagration-to-detonation transition.

The current research program, as a part of an ongoing effort to understand flame propagation fundamentals, was conducted with a focus on dust fuels. A 5m³ vented initiating vessel and interconnected pipeline which incorporates active conveyance capability was used for this program.

A systematic investigation of flame propagation speed and arrival time dependencies upon vessel vent area, fuel concentration, and conveyance velocity is presented. A discussion of propagation in the process flow direction, as well as upstream propagation, is also included. Results of the current research are discussed in light of published explosion protection system design guidelines. This research also provides the empirical basis for a parametric study using computational fluid dynamics (CFD), which is presented in a separate paper [4].

REFERENCES

1. NFPA 68, Standard on Explosion Protection by Deflagration Venting, 2007
2. NFPA 69, Standard on Explosion Prevention Systems, 2008
3. K. Chatrathi, J.E. Going, B. Grandestaff, Flame Propagation in Industrial Scale Piping, Process Safety Progress 20 (2001), 286-294.
4. J. Vingerhoets, T. M. Farrell, J. Snoeys, Dust Flame Propagation in Industrial Scale - Part 2: CFD Study of a Conveying Vessel-Pipeline System, Submitted for 9^th Global Congress on Process Safety, San Antonio, April 28 - May 1, 2013.