Adiabatic bomb calorimeter

The heat output is determined by a Parr adiabatic bomb calorimeter in an argon atmosphere (5 atm.). The gas volume of a sample is determined in the same set-up except that the sample is burnt at 1 atmosphere of air in place of argon atmosphere (inert atmosphere) and the volume of gases liberated is measured by a water displacement technique. 

Thne-of-flight (TOF) mass spectrometric analysis of the pyrolysis fragments of di-t-butyl peroxide suggests t-BuCO as the primary product, followed by decomposition of this radical into CHj.253 Elsewhere, the kinetics of the pyrolysis of dimethyl, diethyl, and di-t-butyl peroxides in a modified adiabatic bomb calorimeter have been investigated.254 The lifetime of acyloxy radicals, generated by the photolysis or thermolysis of acetyl propionyl peroxide, have been studied. Chemical nuclear polarization has been used to determine the rate constant for the decarboxylation of these radical intermediates.255... 

ASTM D-2015. Standard Test Method for Gross Calorific Value of Coal and Coke by the Adiabatic Bomb Calorimeter. 

A more recent test method (ASTM D-5865) pertains to determination of the calorific value of coal by either an isoperibol (a calorimeter that has a jacket of uniform and constant temperature) or adiabatic bomb calorimeter. 

In some instances, an adiabatic bomb calorimeter may not be available or the sample may be too small for accurate use. To combat such problems, there is evidence that differential thermal analysis (DTA) is applicable to the determination of the calorific value of coal. Data obtained by use of the DTA method are in good agreement with those data obtained by use of the bomb calorimeter (Munoz-Guillena et al., 1992). 

ASTM D240 Automated adiabatic bomb calorimeter ... 

Other methods using an adiabatic bomb calorimeter (ASTM D-2015, ASTM D-5865) are also available. 

P9-10(- The ARSST adiabatic bomb calorimeter reactor can also be used to determine the reaction orders. The hydrolysis of acetic anhydride to form acetic acid was carried out adiabatic ally... 

Hassel (241) used pressure DSC (oxygen at 500 psig) to determine the heat of combustion of selected coal samples. The results were in good agreement with adiabatic bomb calorimeter results. 

More widely used is the adiabatic bomb calorimeter, shown in Figure 5. The sample is placed in the crucible, in contact with an ignition wire. The crucible is placed in a strong bomb of stainless steel, which is sealed firmly and pressurised to about 25-30 atm with oxygen. The bomb is placed inside a container with a measured amount of water. This is carefully supported within a shielding container with an outer jacket. This shield contains an electrically conducting solution with a heater, or some other means of temperature control. Thermistor sensors measure the temperature of the inner eontainer, and of the outer jacket. Having... 

D 2015 (1995) Test method for gross calorific value of coal and coke by the adiabatic bomb calorimeter D 2382 (1988) Test method for heat of combustion of hydrocarbon fuels by bomb calorimeter (high-precision method)... 

ASTM. 201 Ig. Test Method for Gross Calorific Value of Coal and Coke by the Adiabatic Bomb Calorimeter (ASTM D2015). Annual Book of ASTM Standards, Section 05.05. American Society for Testing and Materials, West Conshohocken, PA. 

Adiabatic bomb calorimeters or isoperibolic calorimeters are used to determine the heat of combustion of foodstuffs. Although the values may be important in the context of process safety, they are mainly used to calculate caloric values of food for human nutrition or when foods (usually oils) are used as energy sources for engines. 

The adiabatic bomb calorimeter consists of a massive container (the bomb) and a stirred water bath surrounding the bomb (Figure 4.2.3). The whole device is immersed in a second water bath. The reaction is initiated inside the bomb, which contains the reactants (e.g., by ignition in case of oxidations). To ensure adiabaticity, the temperature of the external water bath is continuously readjusted to eliminate the heat loss to the external water bath. 

The most common device for measuring A (7is an adiabatic bomb calorimeter (Fig. 1.17). The process under study is initiated inside a constant-volume container, the bomb . The bomb is immersed in a stirred water bath, and the whole device is the calorimeter. The calorimeter is also immersed in an outer water bath. The water in the calorimeter and of the outer bath are both monitored and adjusted to the same temperature. This arrangement ensures that there is no net loss of heat from the calorimeter to the surroundings (the bath) and hence that the calorimeter is adiabatic. 

Fig. 1.17 A constant-volume adiabatic bomb calorimeter. The bomb is the central vessel, which is strong enough to withstand high pressures. The calorimeter (for which the heat capacity must be known) is the entire assembly shown here. To ensure adiabaticity, the calorimeter is immersed in a water bath with a temperature continuously adjusted to that of the calorimeter at each stage of the combustion.

---