Adiabatic self-heating process

The Sikarex safety calorimeter system and its application to determine the course of adiabatic self-heating processes, starting temperatures for self-heating reactions, time to explosion, kinetic data, and simulation of real processes, are discussed with examples [1], The Sedex (sensitive detection of exothermic processes) calorimeter uses a special oven to heat a variety of containers with sophisticated control and detection equipment, which permits several samples to be examined simultaneously [2]. The bench-scale heat-flow calorimeter is designed to provide data specifically oriented towards processing safety requirements, and a new computerised design... 

Chapter 4 An adiabatic self-heating process recorder 4.1 Introduction... 

Structure and performance of the air bath of the adiabatic self-heating process recorder... 

Three kinds of Pyrex glass open cells, i.e., the open-cup cell, the draft cell and the touch-flow cell, as well as one kind of Pyrex glass closed cell, which each have a capacity of about 2 cm are available for the adiabatic self-heating process recorder. The three kinds of glass open cells are shown in Fig. 19. 

The adiabatic self-heating process recorder, by means of which it is possible to calculate easily, simply and with certainty the heat generation data of a chemical of the TD type, including every gas-permeable oxidatively-heating substance, is, therefore, sufficiently useful, so far as our purpose is to calculate the Tc for a chemical of the TD type, including every gas-permeable oxidatively-heating substance, having an arbitrary shape and an arbitrary size, placed in the atmosphere under isothermal conditions. 

Preheating of the air bath of the adiabatic self-heating process recorder and the choice of a nominal in the adiabatic self-heating test, which is started from the nominal J, performed for 2 cm of a chemical of the TD type confined in the closed cell... 

It is always indispensable for almost all self-heating chemicals, irrespective of whether they are of the TD type or of the AC type, to determine the or the T, of each run by inserting the reference cell assembly into the adiabatic jacket in the adiabatic self-heating process recorder, or into the aluminium block bath in the isothermal storage testing device, prior to the insertion of the sample cell... 

Once the indicator of the analog D.C. microvoltmeter reaches the graduation line of zero at the center of the scale span of the meter, the adiabatic control by means of the adiabatic self-heating process recorder and the record of the selfheating process, in the early stages, of 2 cm of the chemical confined in the... 

Once the temperature of the chemical in the cell reaehes a temperature preset on the two-pen strip chart recorder, the limit switch works in order that the main power supply to the adiabatic self-heating process recorder may be cut automatically. However, It has been made an established rule in the two kinds of adiabatic tests, which are started each from a T performed for 2 cm of a chemical of the TD type, including every gas-permeable oxidatively-heating substance, to interrupt each test, as soon as the temperature of the chemical in the cell increases by the definite value of AT of. 25 K from the T, in the adiabatic self-heating test, or from the corresponding standard temperature in the adiabatic oxidatively-heating test. Some reasons why a value of AToi. 25 K was chosen as the definite value of AT m the two kinds of adiabatic tests are explained in the following subsection. 

In the case of the digital record of the self-heating process exemplified in Table 5, the digital D.C. microvoltmeter indicates that the exact value of the T, of this run is 3111.5 jUV. This value of T, is determined, based on the fact that the indication of the digital D.C. microvoltmeter has fluctuated constantly between 3111 and 3112 juV for 1 to 2 h after the thermal equilibrium state has been attained around the reference material charged in the open-cup cell and inserted into the adiabatic jacket maintained at the nominal T, of 76 °C in the adiabatic self-heating process recorder. 

The sample cell assembly thus prepared is inserted into the adiabatic jacket set in the air bath of the adiabatic self-heating process recorder, and nitrogen gas is supplied into the draft cell at a flow rate of 2 cmVmin. 

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