Bomb combustion

Figure Bl.27.3. Typical static combustion bomb. (Reproduced with penuissiou from A Galleucamp Co. Ltd.)...

For substances containing elements additional to C, H, O and N a rotating bomb calorimeter is generally used. A typical rotating bomb calorimeter system is shown in figure B 1.27.4. With tiiis calorimeter considerably more water is added to the combustion bomb and the continuous rotation of the bomb both about the cylindrical axis and end over... 

J. L. Murphy D.W. Netzer, A1AA J 12 (1), 13-14 (1974) CA 80, 135474 (1974) Color schlieren of AP are photographed in a. N-purged combustion bomb at 100—lOOOpsig to study AP deflagration and AP-binder sandwich combustion. The method provides more complete behavioral data during the combustion process... 

Combustion, bomb/tube combustion, ignition, pyrolysis... 

In the Antek Fluoride Analyzer, a pyrolysis furnace is combined with an ion-specific electrode cell (ISE). Table 8.9 compares this specific analyser to a conventional combustion bomb. 

Most static-bomb calorimeters used are of the isoperibol type, such as the one in figure 7.1. Here, the bomb A is a pressure vessel of 300 cm3 internal volume. Combustion bombs are usually made of stainless steel and frequently have an internal platinum lining to prevent corrosion. In a typical high-precision experiment, the platinum ignition wire B connects the two electrodes C, which are affixed to the bomb head. A cotton thread fuse D (other materials such as polyethene are also used), of known energy of combustion, is weighed to a precision of 10-5 — 10-6 g and tied to the platinum wire. A pellet E of the compound... 

R. L. Nuttall, S. Wise, W. N. Hubbard. Combustion Bomb Reaction Vessel for Spontaneously Combustible Materials. Rev. Sci. Instrum. 1961, 32, 1402-1403. 

One of the simplest calorimetric methods is combustion bomb calorimetry . In essence this involves the direct reaction of a sample material and a gas, such as O or F, within a sealed container and the measurement of the heat which is produced by the reaction. As the heat involved can be very large, and the rate of reaction very fast, the reaction may be explosive, hence the term combustion bomb . The calorimeter must be calibrated so that heat absorbed by the calorimeter is well characterised and the heat necessary to initiate reaction taken into account. The technique has no constraints concerning adiabatic or isothermal conditions hut is severely limited if the amount of reactants are small and/or the heat evolved is small. It is also not particularly suitable for intermetallic compounds where combustion is not part of the process during its formation. Its main use is in materials thermochemistry where it has been used in the determination of enthalpies of formation of carbides, borides, nitrides, etc. 

Determination of Mercury, Fluorine, Boron, and Selenium. The Determination of Mercury. A coal sample is decomposed by igniting a combustion bomb containing a dilute nitric acid solution under 24 atm of oxygen. After combustion, the bomb washings are diluted to a known volume, and mercury is determined by atomic absorption spectrophotometry using a flameless cold vapor technique. 

The trade mark of the present type of alloy is "Type 20 alloy . Parr combustion bombs are described in Refs 16 29, and on pp 16-17 of Ref 16 are given cross section views of "plain jacket calorimeter, series 1300 (Fig 8) and of "adiabative calorimeter, series 1200 (Fig 9)... 

Coal can be analyzed by thermogravimetry (TG), oxygen combustion bomb, total sulfur analysis, x-ray fluorescence (XRF), atomic absorption (AA) spec-... 

W. N. Hubbard, C. Katz, and G. Waddington, A rotating combustion bomb for precision calorimetry. Heats of combustion of some sulfur-containing compounds,. Phys. Chem. 58 142-152 (1954). 

Freedman, B., Bagby, M. O., Callahan, T. J., and Ryan, T. W. III. 1990. Cetane Numbers of Fatty Esters, Fatty Alcohols and Triglycerides Determined in a Constant Volume Combustion Bomb. In SAE Techn. Pap. Ser.. Warrendale PA Society of Automotive Engineers (Paper No. 900343). 

Parr adiabatic calorimeter containing a Parr double-valve oxygen combustion bomb. The water equivalent of the calorimeter was determined from the combustion of a weighed sample of benzoic acid standardized by the National Bureau of Standards (NBS). The agreement between results of any two acceptable runs was better than 0.10%. 

Bomb Pressure Correction. Any change in the operating pressure of the combustion bomb results in a change in the water equivalent (heat capacity) of the calorimeter. However, the difference is less than 1 cal./° C. when operating in the 15-450 p.s.i.g. range of pressure and is therefore negligible. 

The AH° of reaction at 298.16° K. of oxygen difluoride with hydrogen was measured using a Parr fluorine combustion bomb modified to contain a metal ampoule employing a burst diaphragm. This modification permits heat of reaction measurements on systems where reaction occurs spontaneously upon mixing the reactants. The AH° of the reaction OFt - HtO + 2HF (infinite dilution) was found... 

Apparatus and Procedure. The thermochemical measurements were made using a Parr fluorine combustion bomb and a National Bureau of Standards (NBS) isothermal calorimeter (No. 63090) manufactured bv the Precision Scientific Co. The bomb cylinder and all internal parts or the bomb were Monel. A Monel ampoule was fitted into the top of the bomb to retain the OF2 sample. The ampoule apparatus reduced the internal volume of the bomb from 380 to 315 cc. The ampoule screws... 

Figure 1. Nickel Parr combustion bomb with ampoule...

The standard calorimeter system for this series of experiments was specified as the NBS calorimeter containing the Parr fluorine combustion bomb plus sample ampoule. The standard bomb was defined as the Parr fluorine combustion bomb plus sample ampoule minus the water, the benzoic acid pellet, the Hastelloy cup containing the pellet, the oxygen, and the nitrogen used to pressurize the ampoule. 

Warning Never connect a gas cylinder directly to a closed system that is not specially designed to withstand high pressures (such as a combustion bomb for heats of combustion). Even when a regulator is used, remember that the diaphragm valve may slowly leak arrange for some kind of safety pressure release, if only a rubber tubing connection that can be easily blown off. 

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