The use of wet dust extractors for the prevention of dust explosions in sugar production and handling.

Abstract

Sugar is combustible and presents an explosion hazard if ignited after it is dispersed as an airborne dust cloud. The handling of sugar fines from crystalline sugar can trigger an explosion. The finer the sugar, the greater the risk of an explosion. Additionally, sugar milling designed to obtain fine particles represents a potential ignition source.  In sugar handling and production facilities, fines can accumulate on production floors, along conveyor belts, on machinery, in hot rotary dryers and in steel storage and conditioning silos, in dust collectors, as well as on horizontal surfaces.  When sugar is moved or disturbed, it becomes airborne and exposed to oxygen. At that point, an ignition source can result in multiple explosions. Often times a small initial explosion occurs followed by a larger secondary explosion. The first explosion creates pressure waves that can add turbulence and increase dust loading and then create a large ignition source.  The National Fire Protection Association (NFPA) codes that apply to sugar processing are NFPA 68 (Explosion Protection by Deflagration Venting); NFPA 69 (Explosion Prevention Systems) and NFPA 654 (Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate Solids). NFPA 61 (Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities) protects lives and property from fires and dust explosions in facilities handling, processing, or storing bulk agricultural materials, their byproducts, or other agriculture-related dusts and materials. Finally, NFPA 652 (Fundamentals of Combustible Dust) provides the minimum requirements to be met to achieve duct explosion protection and includes the requirement for a Dust Hazard Analysis to be performed. To protect processing equipment and personnel, a multitude of technical measures is often required. They include passive devices (explosion vents), active devices (dust mitigation systems specifically designed to prevent explosions as well as explosion suppression equipment), as well as explosion isolation. Careful attention to prevention, mitigation and isolation will ensure the protection of both personnel and facility.  Wet dust extractor systems are designed to prevent combustible dust explosions and are thus safe and reliable. Wet dust extraction systems also typically have a lower initial acquisition cost as well as have a lower operating cost than baghouse type dust collectors.