Combustion particulates

Explosion hazard when treating combustible gases and/or collecting combustible particulates... 

NFPA 650 Standard for Pneumatic Conveying Systems for Handling Combustible Particulate Solids, 1998 edition. National Fire Protection Association, Quincy, MA. 

NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, 1997 edition. 

Notification of intent to comply Product of incomplete combustion Particulate matter... 

PAH PAN PBN PCT PES PHREEQC PIC PM PMATCHC PM-10 PM-2.5 PRB PUREX PW PWR PZC Polycyclic aromatic hydrocarbon Peroxyacetylnitrate Peroxybenzoylnitrate Product consistency test Plasma emission spectroscopy pH redox equilibrium calculations (computer program) Product of incomplete combustion Particulate matter Program to manage thermochemical data, written in C++ Particulate matter with an aerodynamic diameter <10 p,m Particulate matter with an aerodynamic diameter <2.5 p,m Powder River Basin Pu-U-recovery-extraction Purex waste Pressurized water reactor Point of zero charge... 

NFPA 654 (2006) Standard for the prevention of fire and dust explosions from the manufacturing, processing and handling of combustible particulate solids. (National Fire Protection Association). 

Particulates are another source of respiratory irritation when inhaled. In urban environments, diesel exhaust particles and fly ash residue from power plant oil combustion are the main contributors of respirable particulates of less than 10 pm diameter (PM 10). These contain mixtures of lipo-philes and hydrophiles including various metals, acid salts, aliphatic hydrocarbons, PAHs, quinones, nitroaromatic hydrocarbons, andaldehydes. 151 Diesel combustion particulates contain large surface areas that can adsorb large quantities of organic compounds and deliver these to respiratory tract tissue. Other inhaled particulates can adhere to lung surfaces and adsorb and bond other vapors that are inhaled, thereby increasing their toxicities. PM2.5 particulates (those with diameters of less than 2.5 pm) that reach the lower respiratory tract as far as the alveoli are more toxic than PM 10 particulates of the same composition. 16 ... 

The findings can be interpreted only in terms of the presence of both toxic and nontoxic lead in the exhaust. The ratio of these largely determines catalyst durability, and this ratio appears to be very sensitive to the many parameters which affect combustion. Particulate lead products are nontoxic, whilst toxic forms may be organo lead and/or partially oxidized forms of TEL and/or lead halides or oxyhalides if halide scavengers are present in the fuel. The toxic forms are probably present only as a very minor portion of the total lead in the exhaust. 

The nanoscale materials considered in this chapter are solid materials with primary particles sizes ranging from 1 to 100 nm (10 to 1000 A), as defined in Chapter 1 of the first edition (1). Materials referred to as powders are simply classified through observation rough powder (1 mm to 40 p.m, optical microscope), fine powder (40 p,m to 1 p,m, optical microscope), and superfine powder (<1 p,m, only visible by electron microscope). The latter, superfine powder or nanoparticles, may correspond to the primary particle. These nanoparticles are usually in the form of smoke, combusted particulates, and dispersed primary particles. Some rough and fine powders may be composed of primary particles if the surface area is high. The microstructure of a pellet or powder is important, because the chemical reaction starts from the surface (favored for small crystals) and gas diffuses through the void channels. The morphology controls the reaction rate, which is one of the main concerns in this chapter. 

An afterburner can be expected to achieve between 80 % and 98 % efficiency for burning the combustible particulates emitted from the rotary furnace. Hot gases from the afterburner can be ducted through a recuperator and can assist in preheating the combustion air to the main furnace burner. Recuperators offer an energy saving of up to 15 %. 

Negative pressure dust control and pneumatic conveying systems usually have the exhaust fan on the clean air side of the dust collector or filter receiver, especially if the dust or conveyed solids are combustible. NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate Solids , permits the passing of combustible particulate solids through a fan or blower under certain conditions. See NFPA 654, 2006 Edition,... 

Combustible dust is a combustible particulate sohd that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regard-... 

List five process industries which process combustible particulate materials and in which there is therfore the potential for dust explosion. 

NFPA 61, Fires and Dust Explosions in Agricultural and Food Products Facilities NFPA 650, Pneumatic Conveying Systems for Handling Combustible Materials NFPA 654, Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids NFPA 655, Prevention of Sulfur Fires and Explosions... 

Thus analysis of both combustion particulates and salts is important in evaluating the impact of particulate deposition. 

The Chemical Safety Board (CSB) has found that current MSDSs do not always effectively communicate to employers and workers necessary information about combustible dust hazards or ways to prevent them. A CSB survey found that nearly half of MSDSs for known combustible particulate materials contained no dust explosion warnings, only seven referenced NFPA standards, and few contained practical information. Since the CSB study, OSHA has revised the HazCom requirements. Under the revisions, combustible dust hazards must be addressed on labels and SDSs. Label elements are provided for combustible dust in the final HCS and include the signal word Svarning and the hazard statement May form combustible dust concentrations in the air. For chemicals in a solid form that do not present a combustible dust hazard, but may form combustible dusts while being processed in normal downstream uses, OSHA allows the chemical manufacturer some fiexibility in labeling requirements. The manufacturer or importer to may transmit the label to the customer at the time of the initial shipment, but the label does not need to be included with subsequent shipments unless it changes. This provides the needed information to the downstream users on the potential hazards in the workplace, while acknowledging that the solid metal or other materials do not present the same hazards that are produced when these materials are processed under normal conditions of use. 

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