Safety in Particulate Systems

Home Page TOPIC AREAS The Significance of PT Formation from Gas Formation from Liquid Comminution, Attrition Size Enlargement Particle Physics Particle Characterization:    Non-Optical Methods    Optical Methods Storage / Discharge:    Mechanics: wall stress    Dynamics: flow Pneumatic Conveying Fluidized Bed Mixing and De-mixing Separation by Size P./Gas Separation P./Liquid Separation Dispersion in Fluids Rheology Reaction Heating, Drying Safety Simulation, Modeling Specific Applications

NATIONAL EMPHASIS ON COMBUSTIBLE DUST After a deadly explosion at a sugar refinery in 2008 the Occupational Safety and Health Administration (OSHA) has issued a directive (CPL 03-00-006) initiating a National Emphasis Program (NEP) on Combustible Dust. OSHA offices are required to begin inspections of sites that handle combustible dusts, specifically targeting dust explosion hazards. If your facility handles such powders then read OSHA's Combustible Dust National Emphasis Program [PDF file] Web Tutorials (not ERPT) Some Hazardous Aspects of Particle Technology Web Sites of Educational Interest GESTIS-DUST-EX is a database with the combustion and explosion characteristics of over 4,000 powders from many different industries, with the financial support of the European Commission. These data are intended to illustrate the hazards and are not intended to be adopted in designing small- or large-scale processes. Please read and heed their disclaimer statement. -- www.hvbg.de/e/bia/gestis/expl/index.html Chilworth Technology posts articles on dust explosions and offers courses in safe process design and safe handling of powders. The Fike Company describes tests and equipment to deal with powder explosions. -- www.fike.com/english/products/explosion_protection.html Oseco, Inc., answers Frequently Asked Questions (FAQs) about rupture disks -- www.oseco.com/pages/faq.html. Purest Colloids, Inc., has a product line and Web site that could be the basis for an interesting classroom discussion. Their Meso-word Visualization zooms in on small objects from hair to dust mites to pollen to E. coli to silver nanoparticles. (You may need to click "Start animation" twice to get it going.)

The Process Safety Beacon The Center for Chemical Process Safety (CCPS) -- an AIChE-Technical Industry Alliance -- has publiushed a series of one-page bulletins (in several languages), each of which provides photos and a brief description of an industrial incident and discusses what can be done to avoid or minimize the damage from such incidents. We have listed under the appropriate hazard category links to PDF files for English versions of those bulletins that are related to manufacturing processes that involve particulate materials. Miscellaneous or Multiple Problems Regional Power Failure - Would your fluidized catalytic reactor (or other processes with the potential to release high energy or pollution be safe if the electric grid failed? [Beacon for 2004 Mar] Plant Startup - How often does a shutdown and restart this occur at your plant? Are your shutdown and startup procedures reviewed and updated whenever the routine operating procedures change? Here are some tips for avoiding unexpected trouble. [Beacon for 2005 Dec] Fire Volatiles from Particles Cause Fire in a Screener - Particles containing volatiles may produce an explosive atmosphere that the particles alone would not cause. Static electricity generated by particle collisions may provide a source of ignition. [Beacon for 2003 July] Old Spill Causes Fire - Spills that fall or are swept or washed into floor drains, sewers, corners, and cable trays can come back to haunt you with disastrous consequences. [Beacon for 2006 July] Underpressure Rapid discharge from the bottom of a bin whose air relief inlet vent is disfunctional can result in inward collapse of the bin walls as the air pressude inside drops below the 14.7 pounds er square inch outside. The air intake may be restricted due to the vent being plugged with bugs or bent or undersized or covered with a cloth or a plastic bag. Overpressure Reaction Ruptures Transfer Line - Unstable materials should not be allowed to stand in transfer lines or storage bins. [Beacon for 2003 Mar] Polymerization Bursts Raw Material Containers - Monomers can react even before a catalyst is added. Heed deadlines for use, avoid high temperatures or humidities in storage facilities, and monitored containers for bulging, heat, or other signs of premature reaction. [Beacon for 2006 Jan] Explosion Heat of Adsorption Triggers Explosion - You don't need a spark. [Beacon for 2003 Apr] Static Electricity - Be sure to ground and bond transfer piping and and storage bins when handling combustible dusts [Beacon for 2006 Aug] Dust Explosion - Cleaning up a spill or the area can create an explosive dust cloud, a small explosion can cause additional dust on pipes and walls to fall and create a larger explosive dust cloud or fire. [Beacon for 2003 Sept] Dust Explosion - A pound of coal dust has the explosive power of seven pounds of TNT. How many pounds of flammable dust are present as spills and settling on high rafters and pipes in your plant? [Beacon for 2006 May] Toxicity Pressure Relief - What's wrong in these photos? What do your plant photos look like? Avoid frightening experiences and injuries by reviewing rarely-used discharge conduits. [Beacon for 2006 Mar]

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