Explosives flares

Potassium chlorate, KCIO3, acts as an oxidizing agent in matches, explosives, flares, and fireworks. In the equation below, it is formed from the element chlorine and potassium hydroxide. 

This low viscosity resin permits cure at low (70°C) temperatures and rapidly develops excellent elevated temperature properties. Used to increase heat resistance and cure speed of bisphenol A epoxy resins, it has utihty in such diverse appHcations as adhesives, tooling compounds, and laminating systems. A moleculady distilled version is used as a binder for soHd propellants (see Explosives and propellants) and for military flares (see Pyrotechnics). Its chief uses depend on properties of low viscosity and low temperature reactivity, particularly with carboxy-terminated mbbers. 

Some vent streams, such as light hydrocarbons, can be discharged directly to the atmosphere even though they are flammable and explosive. This can be done because the high-velocity discharge entrains sufficient air to lower the hydrocarbon concentration below the lower explosive limit (API RP 521, 1997). Toxic vapors must be sent to a flare or scrubber to render them harmless. Multiphase streams, such as those discharged as a result of a runaway reaction, for example, must first be routed to separation or containment equipment before final discharge to a flare or scrubber. 

Group 2 Nitrate/metal/sulphur compositions Compositions with >65% chlorate Black powder Nitrate/boron compositions Burn violently Large firework shells Fuse unprotected signal flares Non-pressed report bullets (bird scarers) Report cartridges (unpacked) Black matches (uncovered) Accelerating single-item explosions... 

Group 3 Nitrate/metal compositions without sulphur Compositions with <35-65% chlorate Compositions with black powder Lead oxide/silicon with >60% lead oxides Perchlorate/metal Burn fast Large firework shells Fuse protected signal flares Pressed report cartridges in primary packagings Quickmatches in transport packagings Waterfalls Silver wheels Volcanoes Black powder delays Burn very violently with single-item explosions... 

Flare systems are subject to potential flashback and internal explosion since flammable vapor/air mixtures may be formed in the stack or inlet piping by the entry of air, and the pilot constitutes a continuous ignition source. Flares are therefore always provided with flashback protection, which prevents a flame front from travelling back to the upstream piping and equipment. Design details are described later. 

Flare Gas - Molecular weight, lower explosive limit, density at flare tip, fraction F of heat release radiated by the flame. 

Cl = Lower explosive limit concentration of flare gas in air, volume fractions... 

Some vessels are provided with two full-size relief valves so that one can be changed with the plant on line. On the plant side of the relief valves, isolation valves are usually provided below each relief valve, interlocked so that one relief valve is always open to the plant (Figure 10-2). If the relief valves discharge into a flare system, it is not usual to provide such valves on the flare side. Instead the relief valve is simply removed and a blank fitted quickly over the end of the flare header before enough air is sucked in to cause an explosion. Later the blank is removed and the relief valve replaced. 

Roussakis, N. 1988. The Hazard of an Oil Storage Tank Explosion from Lightning Strike at a Flare Stack. Technical Paper (May 1988). Westech Industrial Limited, Calgary, Alberta, Canada... 

Roussakis, N. and Lapp. K. 1989. Prevention of Oil Storage Tank Explosions m Flaring Operations. Paper presented at the Canadian Petroleum Association Accident Prevention Committee, March 20, 1989, Calgary, Alberta, Canada. 

Flames were first observed at or near an unoccupied caboose. A flash fire resulted, propagating toward the punctured car area. An orange flame then spread upward, and a large vapor cloud flared with explosive force. Estimates of the time lapse between these occurrences range from 2 to 30 seconds. Almost immediately thereafter, a second, more severe, explosion was reported. ... 

W = required vapor capacity in pounds per hour, or any flow rate in pounds per hour, vapor relief rate to flare stack, Ibs/hr W(. = charge weight of explosive, lb Wj. = effective charge weight, pounds of TNT for estimating surface burst effects in free air W, = required steam capacity flow or rate in pounds per hour, or other flow rate, Ib/hr Whe = hydrocarbon to be flared, Ibs/hr Wtnt equivalent charge weight of TNT, lb Wl = liquid flow rate, gal per min (gpm)... 

U = lateral wind velocity, ft/sec Uj = flare tip velocity, ft/sec UEL = upper explosive or flammable limit, percent of mixture of flammable gases only in air... 

In solid form, Mg is difficult to ignite because heat is conducted rapidly away from the source of ignition it must be heated above its mp before it will bum. However, in finely divided form it may be ignited by a spark dr the flame of a, match. Mg fires do not flare up violently unless there is moisture present. Therefore it must be kept away from w, moisture, etc. It m y. be ignited by a spark, match flame, or even spontaneously when the Mg is finely divided and damp, particularly with w-oil emulsion. Also, Mg reacts with moisture, acids, etc to evolve H2 which is a highly dangerous fire arid explosion hazard (Ref 23)... 

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