外文翻译-应对煤尘.doc

1、翻译部分英文原文Coping with Coal DustMahr, Daniel, Michael A.Plants designPlants can no longer sweep coal dust under the rug and ignore the health and safety hazard it present , because a single spark can cause a dust explosion that could put a plant out of service, perhaps permanently. Managing dust in a p

2、ower plant begins with good housekeeping, followed by retrofits using properly designed equipment.Courtesy: Chemical Safety BoardOn February 7,2008, at about 7:15 p.m., a series of huge explosions and fires occurred at the Imperial Sugar refinery northwest of Savannah, Georgia, causing 14 deaths and

3、 injuring 38 others, 14 seriously. The facility, which converted raw cane sugar into granulated sugar, had a material-handling system that included the familiar railcar un-loader, belt conveyors, bucket elevators, and silo storage. The explosions were fueled by massive accumulations of combustible s

4、ugar dust throughout the packaging building.The initiating explosion occurred in the enclosed belt conveyor below the silos. That explosion lofted the dust accumulated on floors and elevated surfaces throughout the buildings. Secondary explosions and fires heaved thick concrete floors and collapsed

5、brick walls, blocking stairwells and exit routes. The destruction, as shown in the photo above, was complete.The U.S. Occupational Safety and Health Administration (OSHA) reports that between 1980 and 2008, 422 combustible dust incidents were reported across 64 different industries; electric power g

6、enerating utilities experienced 28 incidents. The U.S. Chemical Safety and Hazard Investigation Board (CSB) investigates and documents the causes of these industrial dust explosions. Each of the CSB dust explosion reports suggests a common cause: Companies and their employees failed to recognize the

7、 implicit danger of airborne and accumulated dust.The explosion at the Imperial Sugar plant prompted the U.S. House of Representatives to pass a bill requiring OSHA to adopt the National Fire Protection Association (NFPA) recommendations to prevent explosions caused by combustible dust (see Five Req

8、uirements for a Dust Explosion), although it never became law.Today, OSHAs instruction No. CPL 03-00-008 is the guiding directive for controlling dust in manufacturing facilities. CPL 03-00-008 and NFPA 654 define the conditions under which plants must immediately remove dust accumulations that are

9、1/32 inch thick. OSHA standard No. 29 CFR 1910.269(v)(ll)(xii) requires the elimination or control of ignition sources when coal-handling operations may produce a combustible atmosphere. NFPA 654, which includes a comprehensive list of dust control, ignition sources, and damage control provisions, i

10、s also an invaluable referenceA good understanding of what these instructions require (and following through on upgrades, as required) will make your next OSHA inspection much less stressful. The sidebar Prepare for Inspections, Not Citations describes what happens during a typical OSHA visit.The Ch

11、allenge with Handling CoalCoal-fired power plants typically store coal outdoors and normally avoid using enclosed bucket elevators, making the design of a coal-handling system unique and much different than, for example, a grain-handling system at an export terminalMost coal-fired plants have crushe

12、rs, and those in northern climates will often feature enclosed transfer houses and conveyor galleries. Day silos store one or more shifts supply of coal within the power block for operating reliability. Consequently, devastating fires and explosions such as those that occurred at Imperial Sugar and

13、at grain export terminals, particularly during the 1970s, are an ever-present threat at coal-fired plants that ignore basic safety and housekeeping precautions.At coal-fired plants, high-capacity conveying systems handle thousands of tons of coal per hour. When even a small fraction of this tonnage

14、is released and becomes airborne, an unacceptable danger is present. The danger escalates because the conveyed product is also flammable and may reach explosive concentrations. Airborne dust eventually settles on a variety of surfaces and over time; thick layers accumulate in less-visible or inacces

15、sible areas. These accumulations fuel the most devastating events when a small initial explosion shakes dust-laden equipment, piping, conduit, ducts, and structures, thereby propelling the dormant fuel into a dense, flammable cloud that feeds a rapidly expanding fireball. These secondary explosions

16、typically cause the majority of the damage in a plant.Consider the bulldozer in Figure 2 that is slowly pushing a blade of coal into a mostly empty, below-grade reclaim hopper. As the coal slides from the left into the hopper, it displaces air within the hopper. As the photo shows, the slow-flowing dry coal creates a cloud of dust. The exiting displaced air floats fine coal particles into a coal dust cloud that drifts upward at the right side of the