Experimental Results Contributed to Early Detection of Smouldering Milk Powder as an Integrated Part of Maintaining Spray Drying Plant Safety

Abstract

Smoldering milk powder lumps deposited on dryer walls or falling through the hot air could potentially start a fire or even an explosion in milk powder dryers. Explosive behavior is more frequently experienced in the modern industry, where high production throughputs are desired. It has been known that powder at such a state emits carbon monoxide (CO). The work reported in this article is the study of the characteristics of CO generation during the incomplete combustion of milk powders. The powders used in the study were whole milk and skim milk. Samples placed in a reactor were heated using air at 300°C. The exhaust air of the reactor was continuously measured for CO concentration using a highly sensitive CO analyzer. Temperatures were monitored, and the smoke produced during the combustion of whole milk powder was collected and analyzed using gas-chromatography mass-spectroscopy (GC-MS). Whole milk powder was found to produce significantly higher amounts of CO than skim milk powder. Hydrocarbons, alcohols, and carboxylic acids were tentatively identified during the GC-MS analyses. Results from the study are definitely useful in optimizing the use of an early fire detection system in milk powder plants.

Keywords:

• CO detection
• Fire detection
• Smoke point
• Spray drying
• Volatile analysis

ACKNOWLEDGEMENT

This work was funded by the New Zealand Dairy Board.