Parr calorimeter

Parr Calorimeter (Parr Bomb). A device invented by S.W. Parr in 1912, and improved since then by the Parr Instrument Co of Moline, Illinois. 

The pero)iide calorimeter is so named because routine heat of combustion values are obtained by means of a reaction with solid sodium peroxide in lieu of gaseous oxygen under pressure, which is of ccHirse a great convenience and a safety feature. Because of its compactness and small gas volume, the peroxide calorimeter (without peroxide) is now generally used for heat of reaction measurements. HDL scientists who have given much attention to the problem of reliable and reproducible heat powder measurements have added refinements to the above-named Parr Calorimeter, which led to the design marked Model 1411. 

It should be noted that, prior to Parr, other calorimeters existed which used oxygen under pressure for combustion in closed vessels, namely, those of Berthelot (1881) and its modifications and variations, Berthelot-Vieille, Moreau, Landrieu-Malsallez, and of the Commission des Substances Explosives . Later bombs were those of Mahler (1892), Attwater (1899) and Kast (constructed at Chemisch-Technische Reichsanstalt, New-Babelsberg, near Berlin, Ger)... 

A PET oligomer isolation method has utilised chloroform extraction in a Parr bomb lined with a Teflon-TFE fluoro-carbon resin [40]. The analytics of fluoropolymer processing aids (combustion analysis, XRF, EUR, 19F NMR, OM) have recently been described [29]. Combustion analysis (Parr Oxygen Bomb Calorimeter) can be used for quantitative analysis... 

Note The water equivalent factor includes the heat capacity of the ensemble which includes the calorimeter itself, water bucket with water in it, supports of the bucket, bomb, thermometer and stirring device. These values can be calculated theoretically, but much more accurate results are obtained by combustion of a sample of standard material (such as benzoic acid, supplied by the US Bureau of Standards), the heat of combustion of which has been previously accurately determined. The water equivalent values of the calorimeters and bombs supplied by the Parr Instrument Co are determined by them at the factory... 

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. 

Fig. I. Cross-section or plain jacket oxygen bomb calorimeter. (Parr Inslru mem Co.)...

Further developments in calorimetry include the invention of the twin- calorimeter" by Joule (1845) and its modification by Pfaundler (1869XRef 25,p 543) "phase- change calorimer (isothermal) of Bunsen(Ref 15,p 796 Ref 25,p 547) "labirinth flow calorimeter (Ref 25,p 549) "adiabatic calorimeter (nonisothermal), first used by Richards in 1905 (Ref 15,p 797) and modified by Yost, Osborne others (Ref 25,p 550)(See also Ref 3,p ll6)(Parr adiabatic calorimeter is described in Refs 16 29) "constant- temperature- enviroment calorimeter", first used by Nemst in 1907, was modified by Giauque in 1923(Ref 15>p 797)... 

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)... 

Parr calorimetric bombs and calorimeters are very much in use in the US. These bombs are cylindrical in shape and are provided with covers which can be securely closed against leakage. Detailed descriptions of experimental procedures using Parr oxygen bombs and Patr calorimeters... 

Methods of Organic Chemistry , Interscience, NY, vol l,part 1(1959), 523-654 J.M.Sturtevant, "Calorimetry 26)R.S.Jessup, "Precise Measurements of Heats of Combustion with a Bomb Calorimeter , USNBS Monograph No 7, Washington, DC(1960) 27)S.Glasstone D.Lewis "Elements of Physical Chemistry , VanNostrand, NY(1960) 28)Merriam-Websters (1961), 320 29)Parr Specifications No 1100- 1105 (Describes various bombs and calorimeter and gives literature on Parr apparatuses may be obtained on request from Parr Instrument Co, Moline, Illinois)... 

Experimental. A Parr model 1221 oxygen bomb calorimeter was modified for isothermal operation and to ensure solution of nitrogen oxides (2). The space between the water jacket and the case was filled with vermiculite (exploded mica) to improve insulation. A flexible 1000-watt heater (Cenco No. 16565-3) was bent in the form of a circle to fit just within the jacket about 1 cm. above the bottom. Heater ends were soldered through the orifices left by removing the hot and cold water valves. A copper-constantan thermocouple and a precision platinum resistance thermometer (Minco model S37-2) were calibrated by comparison with a National Bureau of Standards-calibrated Leeds and Northrup model 8164 platinum resistance thermometer. The thermometer was used to sense the temperature within the calorimeter bucket the thermocouple sensed the jacket temperature. A mercury-in-glass thermoregulator (Philadelphia Scientific Glass model CE-712) was used to control the jacket temperature. 

Calibration. The calorimeter was calibrated by burning standardized benzoic acid obtained from the Parr Instrument Co. (AH0 = 197.72 kcal./mole). Measurements were made under conditions paralleling as closely as possible those used during a run. For reasons explained below it was also necessary to determine the heat of combustion of Nujol brand mineral oil. For this purpose the contents of two 1-pint bottles of Nujol were mixed thoroughly and stored in a 1-liter bottle. Runs were made on aliquots withdrawn from this new mixture. Table II includes the results obtained both for the benzoic acid and the Nujol and indicates the precision of the experiment. 

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%. 

Calorimetry. Polymer samples were ground in a Wiley mill, screened through a 100-mesh sieve, and vacuum dried at 35° C. for 15-20 hours. The samples were then pressed into cylindrical V2 X 3/8-inch pellets at 40,000 p.s.i.g. The pellets were then placed in a tared porcelain crucible and weighed. The crucible containing the sample was placed in the bomb of a Parr adiabatic calorimeter, and the sample was burned at an oxygen pressure of 450 p.s.i.g. at 25° C. The heats of combustion of the polymer samples were obtained by applying the following corrections to the experimental values ... 

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... 

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. 

Bomb calorimeter (Parr design), shown with an adiabatic jacket, which may also be used empty as an insulating air jacket. The precision mercury thermometer can be replaced by a high-resolution resistance thermometer or a calibrated thermistor. 

Parr single-valve bomb, shown in contact with bottom of calorimeter pail. One electrical contact is made automatically through the pail to the body of the bomb. The bomb should be mounted on an assembly stand while it is being loaded with the sample. 

Procedure. The successful operation of tliis experiment requires close attention to detail, as there are possible sources of trouble that might prevent the experiment from woridng properly. The basic procedure is very similar for both Parr and Emerson calorimeters. Necessary changes in procedure will be provided by the instructor if an Emerson calorimeter is to be used. Although considerable detail is given below, further details on the operation of the Parr apparatus (including the adiabatic jacket) are available in a manual pubhshed by the manufacturer. ... 

A consulting laboratory is called upon to determine the heating value of a natural gas in which the combustible is entirely methane. They do not have a Sargent flow calorimeter, but do have a Parr bomb calorimeter. They pump a measured volume of the natural gas into the Parr bomb, add oxygen to give a total pressure of 1000 kPa, and explode the gas-02 mixture with a hot wire. From the data they calculate that the gas has a heating value of 3.44 X 10 kJ/m Should they report this value Explain. 

Proximate analyses of the fuel and char were run using a standard laboratory drying oven, muffle furnace, and analytical balance according to ASTM Standard Methods. Ultimate Analysis for percent C, H, N, S, and O in the fuel char, and condensate was conducted by the Chemistry Department, University of California, Berkeley. The energy content of the fuel and char was determined with a Parr Oxygen Bomb Calorimeter. 

Analysis and Calculation. Feed and fecal samples were analyzed for gross energy (Parr Oxygen Calorimeter), cellulose (7), dry matter, and crude protein (1). Apparent digestion of dry matter, cellulose, and energy was calculated as the difference between nutrient intake and fecal excretion, expressed as a percent of nutrient intake. 

Figure 23.3 Cross section of a Parr Solution Calorimeter. Source Reprinted from Parr Instrument Co., Illinois, USA, technical literature.

The Parr Instrument company manufactures combustion bombs, calorimeters, chemical reactors (including tubular and CSTRs), pressure vessels, and related equipment developed specifically for laboratory use. 

Fig. B-35. Bomb calorimeter for the determination of gross energy. (Courtesy, Parr Instrument Company, Moline, III.)...

Figure 2.12 A Bomb Calorimeter. (Courtesy of the Parr Instrument Co.]...

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