Ammonium nitrate decomposition rate

In the context of safety of the process of neutralisation of nitric acid with ammonia, the effects of temperature (160-230°C), pressure (2.3-9.8 bar), and concentrations of ammonium nitrate (86-94%) and of nitric acid (0-4%) upon decomposition rate were studied. 

A lire disaster costing 67 million occurred in Texas City, Texas, on the SS Grandcamp (16 April 1987) due to spontaneous ignition of stored fertilizer in the ship s hold. A release of steam from an engine leak caused the atmosphere of the ammonium nitrate fertilizer to be exposed to temperatures of 100 °C. Ammonium nitrate (NH4NO3) decomposes exothermically releasing 378 kJ/g mol. Its rate of decomposition can be described by the Arrhenius equation ... 

The reported decomposition of ammonium nitrate indicates that the reaction is unimolecular and that the rate constant has an A factor of 1013 8 and an activation energy of 170kJ/mol. Using this information, determine the critical storage radius at 160°C. Report the calculation so that a plot of rcrit versus T0 can be obtained. Take a temperature range from 80°C to 320°C. 

It is worth emphasizing that the reaction scheme above is able to explain not only the stoichiometry of the fast SCR reaction, and specifically the optimal equimolar NO to N02 feed ratio, but also the selectivity to all of the observed products, namely N2, NH4NO3 and N20, which derives from thermal decomposition of ammonium nitrate (Ciardelli et al., 2004b, 2007a Nova et al., 2006b) furthermore it is in agreement with the observed kinetics of the fast SCR reactions, which at low temperature is limited by the rate of the reaction between nitrate and NO. 

Wood and Wise [13] examined the rate of decomposition of ammonium nitrate enclosed in sealed ampoules and kept at temperatures between 200 and 300°C. They found the energy of activation E — 31.4 kcal/mole. 

Several authors noticed that the addition of chromium salts to ammonium nitrate increases the rate of its decomposition Audrieth and M. T. Schmidt [25], Blinov [26], J. Taylor and Sillitto [5], J. Taylor and Whetstone [27], A. J. B. Robertson [12], Shidlovskii [28], Shirai and Ishibashi [29]. 

The increase in the rate of decomposition under the influence of added Cr203 and K2Cr207 is shown on Figs. 171 and 172 respectively.lt has been found that an increase of the rate occurred only at temperatures near to the melting point of the samples. Guiochon [17] also found that cobalt salts increase the rate of thermolysis of ammonium nitrate. Other mineral salts (of manganese, nickel and copper) have a similar but much weaker action. A large number of salts of other metals are without any noticeable action. 

We have investigated the humification of straw, as an example, under constant conditions of humidity and temperature in a climatic chamber (4,18) and separated different fractions according to a modified method of Waksman s proximate analysis. The amount of nitrogen present in these processes is the factor limiting the rate of decomposition. Therefore we added nitrogen in form of ammonium nitrate in a quantity of 1% of straw dry weight to a nutrient solution in one experiment while the nutrient solution had no nitrogen in a parallel experiment. Table I shows the calculated data. 

Alternatively, ammonium nitrate (AN, QCq2 = 20.0 %, begins decomposition at m.p. = 169.9 °C, complete decomposition at 210 °C) has been discussed, however this compound has severe burn rate issues. Furthermore, AN is hygroscopic and shows phase transitions from one polymorph to another at 125.2 °C, 84.2 °C, 32.3 °C and -16.9 °C. Phase stabilized ammonium nitrate (PSAN) and spray crystallized AN (SCAN) are special qualities provided by ICT. 

Ammonium Nitrate. Like AP, the decomposition of AN occurs via complex decomposition mechanisms. Studies performed by Oxley and coworkers indicate two modes of decomposition.[52-54] In the temperature range 200-300 °C, decomposition starts through an endothermic dissociation to ammonia and nitric acid and the formation of the nitronium ion is the rate-determining step (See Scheme II). 

Thermal Decomposition of Liquid Gun Propellant The Liquid Gun Propellant (LGP) tested in the solids recirculation was LP XM-46, which is 24% TEAN (triethanol ammonium nitrate) and 76% HAN (hydroxy-ammonium nitrate. The mixture was diluted 1 3 in water. The diluted LGP was injected at an initial rate of 0.06 gal/min and later increased to 0.1 gal/min. The operation was run in pyrolysis and combustion modes. 

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