Calorimeter, bench-scale

V. Babrauskas, Development of the Cone Calorimeter. A Bench-Scale EHR Apparatus Based on Occggen Consumption, NSBIR 82-2611, U.S. Dept, of Commerce, Gaithersburg, Md., 1982. 

Reaction calorimetry is a technique which uses data on the rate of heat evolution or consumption to evaluate the thermokinetic reaction characteristics needed for reactor scale-up and/or optimization and safety. Since the late seventies, the application of this technique has been steadily growing and reaction calorimeters are now commercially available. Probably the first commercial reactor calorimeter was developed by CIBA-GEIGY (Bench Scale Calorimeter BSC) (see Beyrich et al, 1980 and Regenass et al., 1978, 1980, 1983, 1984, 1985, 1997))... 

Figure 5.4-23. Bench scale reaction calorimeter (adapted from Brogli et a/., 1981).

Brogli, F. et al., Runaway Reactions, 1981, Paper 3/M, 5-6, 10 Unstable plant-scale operation in the catalysed cyclisation by sodium hydroxide to cyclopropanecarbonitrile was investigated using a bench scale calorimeter. Crust formation on the reactor wall, which caused the erratic operation, was eliminated by using liquid alkali instead of solid. 

A discussion of test methodology is beyond the scope of the present paper. However, the fact that established tests do not accurately reflect the behavior of materials in fires has been widely recognized (9), and the search for more meaningful techniques for the evaluation of engineering materials has continued to be a valid research objective. The development of the cone calorimeter, a bench-scale tool for the evaluation of fire properties of materials (10a) at NBS, is of particular significance in this context. 

Because heat of combustion of the volatile product is not the same as that of whole wood, one cannot estimate heat release rate based on mass loss rate as can be done with ideal fuels such as gases, liquids, and some noncharring solid materials. Thus, measuring heat release rate rather than mass loss rate is appropriate for wood and charring materials. Several bench-scale calorimeters have been developed to measure heat release rate of materials (1,11,12,13). 

Babrauskas, Vytenis. Development of the Cone Calorimeter—A Bench-scale Heat Release Rate Apparatus Based on Oxygen Consumption. U.S. Department of Commerce NBSIR 82-2611, 1982. 

In an ideal situation the parameters used to define furniture should be ignition resistance and the rate of generation of heat, smoke and toxic gases. Tests to do this with actual or mock-up full sized furniture are not yet available as final specifications but the Nordtest (28) and NBS furniture calorimeters (29) represent scientific methods while room/ corridor rigs, typically UK DOE PSA FR5 and 6 of 1976 (5) (6) were originally used but are less satisfactory from a scientific point of view. The Californian (30) and Boston tests (31) for public area furniture are essentially simple room tests and are similar in principle to DOE, PSA, FR5 and 6 although the latter do not have pass/fail criteria. Bench scale rate of heat release tests include the NBS cone (29) which, with a code of practice represent a possible alternative but the rate of burning of... 

Babrauskas, V., "Development of the Cone Calorimeter - A Bench-Scale Heat Release Rate Apparatus Based on Oxygen Consumption," 1984, Fire and Materials, 8, 81. 

The Contalab, initially supplied by Contraves, was purchased by Mettler-Toledo, which is now placing less emphasis on this design than on the RC1. Some comments here are appropriate, however, since it is another type of bench-scale calorimeter, and units continue to be used. Its measuring system is based on the heat balance principle, in which a heat balance is applied over the cooling/heating medium. For this purpose, both the flow rate of the coolant and its inlet and outlet temperatures must be known accurately. Figure 3.12 is a schematic plan of the Contalab. 

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... 

Boiling liquid expanding vapom explosion Material producing much gas on decomposition Boiling point Bench scale calorimeter... 

Similar data can also be obtained for vapour pressure systems from the DIERS bench-scale apparatus operated in the open mode (see Figure A2.5). A high back pressure is superimposed on the containment vessel to suppress, boiling of the sample. An adiabatic Dewar calorimeter can also be operated in this mode if it has the facility to vent to an external containment vessel. 

The time to ignition as a function of incident radiant heat flux can also be measured in the ISO ignit-ability test apparatus. This apparatus and its use are described in ISO 5657. Bench-scale heat release calorimeters such as the Cone Calorimeter (Section 14.3.3.2.1) and the Fire Propagation Apparatus (Section 14.3.3.2.3) can also be used to obtain this kind of data. 

There are two intrinsic material characteristics that are related to heat release rate. These two properties are the effective heat of combustion, AHc (MJ/kg), and the heat of gasification, L (MJ/kg). The effective heat of combustion is the ratio of heat release rate to mass loss rate measured in a bench-scale calorimeter ... 

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