Explosion physical energy

Refrigeration Loss of containment of a liquefied gas under pressure and at atmospheric temperature causes immediate flashing of a large proportion of the gas. This is followed by slower evaporation of the residue. The hazard from a gas under pressure is normally much less in terms of the amount of material stored, but the physical energy released if a confined explosion occurs at high pressure is large. 

Additions of crystalline oxidizers such as ammonium nitrate or potassium nitrate to nitrate esters or energetic polymers form composite explosives whose physical structures are heterogeneous. In contrast to homogeneous explosives, the energy density of composite explosives is higher than that of homogeneous explosives. 

In what follows explosions caused by combustion reactions are treated first. Runaway reactions, decomposition and polymerization are a subject of Chap. 3, explosives are treated in Sect. 2.5 and explosions resulting from physical energy in Sects. 10.7 and 10.9. Nuclear explosions are outside the scope of this book. Two types of explosions due to chemical energy are distinguished... 

The energy released in an explosion in a process plant is either chemical or physical ... 

Cyclodimer 3 proved to be somewhat difficult to manipulate, thus contributing to the complexity of its characterization. The bowed diacetylenic linkages revealed in the X-ray data impart surprising physical characteristics to the molecule. The energy-rich hydrocarbon was sufficiently strained that it decomposed explosively upon grinding (i. e. preparing a Nujol mull) or when heated above 80°C. At room temperature, crystals blackened within a few days and apparently auto-polymerized, even when stored under vacuum in the dark. Only dilute solutions of 3 in benzene or pyridine were fairly stable over time, especially when stored cold under an inert atmosphere. 

Physical explosion Any explosion where the energy release is due to a physical, as opposed to a chemical, process. 

It will be noted that , is the specific internal energy of the unreacted explosive, whereas E2 is the specific internal energy of the explosion products at pressure p2 and specific volume v2. These equations are deduced from physical laws only and are independent of the nature or course of the chemical reaction involved. 

This base is used to the minimum possible extent in the final explosive as the water it contains does not contribute to the power and indeed requires energy for its evaporation. All slurry explosives therefore contain further ammonium nitrate in solid form and also a fuel for combustion. The ammonium nitrate is usually in dense form similar to that used in nitroglycerine explosives as this gives the best physical properties. However, it is common practice to mix the explosive hot so that much or all of the solid ammonium nitrate results from crystallisation during cooling. 

Chain reactions can lead to thermal explosions when the energy liberated by the reaction cannot be transferred to the surroundings at a sufficiently fast rate. An explosion may also occur when chain branching processes cause a rapid increase in the number of chains being propagated. This section treats the branched chain reactions that can lead to nonthermal explosions and the physical phenomena that are responsible for both branched chain and thermal explosions. 

The subscript in vessel is for the reactor or building. The subscript experimental applies to data determined in the laboratory using either the vapor or dust explosion apparatus. Equation 6-20 allows the experimental results from the dust and vapor explosion apparatus to be applied to determining the explosive behavior of materials in buildings and process vessels. This is discussed in more detail in chapter 9. The constants KG and KSt are not physical properties of the material because they are dependent on (1) the composition of the mixture, (2) the mixing within the vessel, (3) the shape of the reaction vessel, and (4) the energy of the ignition source. It is therefore necessary to run the experiments as close as possible to the actual conditions under consideration. 

The types of explosions that may occur depend on the confinement of the reactive material, its energy content, its kinetic parameters, and the mode of ignition (self-heating or induced by external energy input). Explosions are characterized as physical or chemical explosions, and as homogeneous or heterogeneous as described in Figure 2.2. 

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