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Drying of Solids: Principles, Classification, and Selection of Dryers
Published in Arun S. Mujumdar, Handbook of Industrial Drying, 2020
Arun S. Mujumdar, Anilkumar S. Menon
Comprehensive tables of vapor pressure data of common liquids, such as water, common refrigerants, and others, may be found in References 2 and 3. For most liquids, the vapor pressure data are obtained at a few discrete temperatures, and it might frequently be necessary to interpolate between or extrapolate beyond these measurement points. At a constant pressure, the Clausius–Clapeyron equation relates the slope of the vapor pressure-temperature curve to the latent heat of vaporization through the relation dPW0dT=ΔHWT(VW−VL)
Characterization of Nanoparticles from Spark Ablation
Published in Andreas Schmidt-Ott, Spark Ablation, 2019
Once the particles have passed the inlet and have been focused into a beam, they are vaporized and ionized. This can be done in a single step or in two sequential steps and either continuously or in a pulsed manner. The vaporization can be either thermal or radiative. When vaporizing the particles thermally, they are continuously accelerated across the vacuum chamber to impact onto a sufficiently heated (often 600°C–1500°C) surface (filament) to flash-vaporize them. They can be ionized already at the heated surface, but it is more common to do this after vaporization by using an electron beam. Electron ionization at 70 eV is standard in an AMS and has the advantage that the obtained particle mass spectra can be compared to the spectra in reference libraries such as the National Institute of Standards and Technology (NIST).
Biomass Drying and Sizing for Industrial Combustion Applications
Published in Shusheng Pang, Sankar Bhattacharya, Junjie Yan, Drying of Biomass, Biosolids, and Coal, 2019
Hamid Rezaei, Fahimeh Yazdanpanah, Shahab Sokhansanj, Lester Marshall, Anthony Lau, C. Jim Lim, Xiaotao Bi
The moisture in a solid may be either unbound or bound. Unbound moisture is removed through evaporation and vaporization. Evaporation is the process by which a liquid phase changes to vapor at a temperature below the boiling point; thus, it is a slow process. Evaporation only takes place on the surface and depends on surface area, airflow speed, relative humidity, and temperature. Evaporation occurs when the vapor pressure of the moisture on the solid surface is greater than the vapor partial pressure in the main stream of the drying medium. Vaporization is the process by which a liquid phase changes to vapor at its boiling point. For pure water, vaporization occurs at a constant boiling point temperature. For a moist biomass particle, vaporization occurs at wet-bulb temperature or higher. As vaporization happens through the bulk, not only the surface, the rate of vaporization does not depend on the surface area, wind speed, or relative humidity. In this case, the vapor pressure of the moisture over the solid is less than the atmospheric pressure [62]. In vaporization, drying is carried out by passing warm air over the product. Along the gas flow direction, the drying gas temperature is decreased and gas humidity is increased (Figure 2.4).
A critical overview of thin films coating technologies for energy applications
Published in Cogent Engineering, 2023
Mohammad Istiaque Hossain, Said Mansour
In general, a source material placed on a metallic boat requires heating until it reaches it is evaporating phase to start deposition. Later, growth of layers occur due to the condensation of the source vapor and the process happens within the low vacuum range between 10−6 and 10−5 Torr to re-route any reaction of the produced vapor and ambient atmosphere (Wu et al., 2022). Such pressure helps in the same mean free path to the chamber inner dimension; hence, the atoms evaporate in a straight geometrical dimension. However, shadowing might occur due to the inaccessibility of atoms to some area of the substrates. Due to the low energy particles, such process sometimes results in less adhesion and coverage of films, which require process optimization. Also, various methods have been adapted to heat the source materials (Hsu et al., 2022). The vaporization rate depends on the rate that molecules leave the source surface and the area of the evaporating surface. The rate that molecules leave the surface is related to the vapor pressure of the evaporant. Figure 3 shows the process chamber layout of a thermal evaporation system to grow the thin films and perovskite films and contacts.
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).
Analytical theory study on latent heat coefficient of grain water vaporization
Published in Drying Technology, 2021
Water vaporization is a spontaneous process of mass transfer heat, work transfer and conversion, which can take two forms: evaporation and boiling. Evaporation can take place at any temperature in an open system, while boiling takes place at a specific temperature in a closed system corresponding to a given pressure condition, as shown in Figure 1.