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Thermodynamic Properties and Equations of State
Published in Robert E. Masterson, Nuclear Reactor Thermal Hydraulics, 2019
where hvl = hv − hl is the enthalpy of vaporization. Thus the enthalpy of vaporization represents the amount of thermal energy required to convert a unit mass of saturated liquid into a unit mass of saturated vapor. Hence it is a tabulated quantity, and for different temperatures and pressures, its values can be found in Appendix G. In a BWR core, its value is approximately 1500 kJ/kg. Sometimes it is easier to discuss what we have just said in terms of a T–h diagram, such as the one shown in Figure 7.14. Inside of the vapor dome the mixture specific volume and the mixture specific enthalpy can be found by combining the relative amounts of each phase between the right hand side and the left hand side of the dome.
Symbols, Terminology, and Nomenclature
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Energy gap* - In the theory of solids, the region between two energy bands, in which no bound states can occur. Enols, alkenols - The term refers specifically to vinylic alcohols, which have the structure HOCR'=CR2. Enols are tautomeric with aldehydes (R' = H) or ketones (R' not equal to H). [5] Enthalpy (H)* - A thermodynamic function, especially useful when dealing with constant-pressure processes, defined by H = E + PV, where E is energy, P pressure, and V volume. [1] Enthalpy of combustion* - The enthalpy change in a combustion reaction. Its negative is the heat released in combustion. Enthalpy of formation, standard* - The enthalpy change for the reaction in which a substance is formed from its constituent elements, each in its standard reference state (normally refers to 1 mol, sometimes to 1 g, of the substance). Enthalpy of fusion* - The enthalpy change in the transition from solid to liquid state. Enthalpy of sublimation - The enthalpy change in the transition from solid to gas state. Enthalpy of vaporization* - The enthalpy change in the transition from liquid to gas state. Entropy (S)* - A thermodynamic function defined such that when a small quantity of heat dQ is received by a system at temperature T, the entropy of the system is increased by dQ/T, provided that no irreversible change takes place in the system. [1] Entropy unit (e.u.) - A non-SI unit of entropy, equal to 4.184 J/K mol. Ephemeris time - Time measured in tropical years from January 1, 1900. Epoxy compounds - Compounds in which an oxygen atom is directly attached to two adjacent or non-adjacent carbon atoms of a carbon chain or ring system; thus cyclic ethers. [5] Equation of continuity - Any of a class of equations that express the fact that some quantity (mass, charge, energy, etc.) cannot be created or destroyed. Such equations typically specify that the rate of increase of the quantity in a given region of space equals the net current of the quantity flowing into the region. Equation of state* - An equation relating the pressure, volume, and temperature of a substance or system. Equilibrium constant (K)* - For a chemical reaction aA + bB cC + dD, the equilibrium constant is defined by: K= aC c aD d aA a aB b
Experimental validation of a wireless monitored solar still for efficient olive pomace drying and distilled water production
Published in Drying Technology, 2023
Antonio Rodríguez Orta, Roque Aguado Molina, Manuel Sánchez Raya, David Vera Candeas, Juan Antonio Gómez Galán
For most applications of solid fuels, the Lower Heating Value (LHV) is used, as the heat contained in combustion products is typically not returned to precombustion temperature. The LHV was estimated from the experimentally determined HHV, the ultimate analysis and the moisture content through Eq. (3). where:LHV = Lower Heating Value of the sample.HHV = Higher Heating Value of the sample.H = Hydrogen content in the sample (wt.%).W = Moisture content in the sample (wt.%, wet basis). = Enthalpy of vaporization of water at 25 °C, equal to 2.4417 MJ kg
Neural computing approach for predicting vaporization enthalpy of pure hydrocarbons and petroleum fractions
Published in Petroleum Science and Technology, 2019
Reza Eghtedaei, Navid Kianoosh Moghaddam, Vali Sarlak, Amir Noori deldar, Alireza Baghban
The enthalpy of vaporization is one of the most significant thermodynamic quantities for a multi-component multi-stage vapor–liquid posing process, and it is the amount of energy that must be added to the liquid substance to transform a quantity of that substance into gas. Also, it is defined as the diverseness between the enthalpy of the vapor at the equilibrium vapor pressure and the enthalpy of the liquid phase at the identical temperature and pressure. Enthalpy flux computations for plenty of single operations involve the enthalpy of vaporization data (Majer et al., 1985; Poling et al., 2001). The values of a particular degree are related to the stability of the intermolecular actions. The enthalpy of vaporization is valuable for engineering works and theoretical researches because of its measurement and correlations. Also, there are plenty of forecasting methods and experimental data for pure compounds in the literature, but because of experimental difficulties, the straight calorimetric data of enthalpy of vaporization for petroleum fractions are not accessible (Daubert and Danner 1997; Gopinathan and Saraf 2001).