Specific decomposition heat

For the effective specific heat capacity, the energy change during decomposition (i.e., decomposition heat) must be considered. The rate of energy absorbed for decomposition (endothermic reaction) is determined by the reaction rate, that is, the decomposition rate that is obtained by the decomposition model (Eq. (2.19)). Combining Eq. (2.19) and Eq. (4.30) gives ... 

The true specific heat capacity of a composite material was obtained by the mle of mixture and the mass fraction of each phase was determined by the decomposition and mass transfer model. The true specific heat capacity of resin or fiber was derived based on the Einstein or Debye model. The effective specific heat capacity was obtained by assembhng the trae specific heat capacity with the decomposition heat that was also described by the decomposition model. The modeling approach for effective specific heat capacity is useful in capturing the endothermic decomposition of resin and was further verified by a comparison to DSC curves. 

Specific heat capacity of material before decomposition, j, Specific heat capacity of material after decomposition, Decomposition heat,... 

The specific heat capacity of a mixture (composite material) is determined by the properties of the different phases and their mass fraction, while the effective specific heat capacity includes the energy needed for additional chemical or physical changes. Consequently, the decomposition heat can be considered to be a part of the effective specific heat capacity as introduced in Chapter 4. The effects due to pyrolysis gases on the specific heat capacity are negligible, as most gases can escape from the material, and thus the mass fraction of the remaining gases is very small. The thermal conductivity of a mixture is determined by the properties of the different phases and their volume fraction. Consequently, the effect due to pyrolysis... 

The theoretical energy requirement for the burning of Portiand cement clinker can be calculated from the heat requirements and energy recovery from the various stages of the process. Knowledge of the specific heats of the various phases, and the heats of decomposition, transformation, and reaction then permits calculation of the net theoretical energy requirement of 1760 kj (420 kcal) for 1 kg of clinker from 1.55 kg of dry CaCO and kaolin (see Clays) (8). 

Traditionally, sodium dichromate dihydrate is mixed with 66° Bh (specific gravity = 1.84) sulfuric acid in a heavy-walled cast-iron or steel reactor. The mixture is heated externally, and the reactor is provided with a sweep agitator. Water is driven off and the hydrous bisulfate melts at about 160°C. As the temperature is slowly increased, the molten bisulfate provides an excellent heat-transfer medium for melting the chromic acid at 197°C without appreciable decomposition. As soon as the chromic acid melts, the agitator is stopped and the mixture separates into a heavy layer of molten chromic acid and a light layer of molten bisulfate. The chromic acid is tapped and flaked on water cooled roUs to produce the customary commercial form. The bisulfate contains dissolved CrO and soluble and insoluble chromic sulfates. Environmental considerations dictate purification and return of the bisulfate to the treating operation. 

The specific electrical conductivity of dry coals is very low, specific resistance 10 ° - ohm-cm, although it increases with rank. Coal has semiconducting properties. The conductivity tends to increase exponentially with increasing temperatures (4,6). As coals are heated to above ca 600°C the conductivity rises especially rapidly owing to rearrangements in the carbon stmcture, although thermal decomposition contributes somewhat below this temperature. Moisture increases conductivity of coal samples through the water film. 

Physical and emical Properties - Physical State at 15 XI and I atm. Liquid Molecular Weight 122.95 Boiling Point at 1 atm 169, 76, 349 Freezing Point -141.7, -96.5, 176.7 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.66 at 16 °C (liquid) Vapor (Gas) Density 4.24 Ratio of Specific Heats of Vapor (Gas) 1.44 Latent Heat of Vaporization 106, 59, 2.5 Heat of Combustion No data Heat of Decomposition Not pertinent. 

Physical and Chemical Properties — Physical State at 15 T7 and 1 atm. Liquid Molecular Weight Mixture Boiling Point at I atm. Decomposes Freezing Point 17, -8,265 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 1.2 at 20 °C (liquid) Vapor (Gas) Density Not pertinent Ratio cf Specific Heats cf Vapor (Gas) Not pertinent Latent Heal of Vaporization Not pertinent Heat of Combustion -15,700, -8750 -366 Heat of Decomposition -50, -28, -1.2. 

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