Condensation of vapor

The term mist generally refers to liquid droplets from submicron size to about 10 /xm. If the diameter exceeds 10 /xm, the aerosol is usually referred to as a spray or simply as droplets. Mists tend to be spherical because of their surface tension and are usually formed by nucleation and the condensation of vapors (6). Larger droplets are formed by bursting of bubbles, by entrainment from surfaces, by spray nozzles, or by splash-type liquid distributors. The large droplets tend to be elongated relative to their direchon of mohon because of the action of drag forces on the drops. 

There is no condensation of vapor or boiling of liquid in part of the exchanger. 

Fumes - Fumes are finely divided solid partieles that are generated by the condensation of vapors. Fumes are generally the by products of sublimation, distillation, and molten metal processes. Particle diameters are generally in the range of 0.1 to 1 /im. 

Fogs are fine airborne droplets usually formed by condensation of vapor. Many droplets in fogs are microscopic and submicroscopic and serve as a transition stage between mists and vapors. 

Water hammer (also known as hydraulic shock) occurs in two distinct ways when the flow of liquid in a pipeline is suddenly stopped, for example, by quickly closing a valve [13], and when slugs of liquid in a gas line are set into motion by movement of gas or condensation of vapor. The latter occurs when condensate is allowed to accumulate in a steam main, because the traps are too few or out of order or in the wrong place. High-pressure mains have been ruptured, as in the following incident. 

Precondensers are recommended for any ejector system when the pressure conditions and coolant temperature will allow condensation of vapors, thus reducing the required design and operating load on the ejectors. This is usually the situation when operating a distillation column under vacuum. The overhead vapors are condensed in a unit designed to operate at top column pressure, with only the non-condensables and vapors remaining after condensation passing to the ejector system. 

These pumps cannot effectively handle condensation of vapors inside the unit, because the capacity is reduced and the condensate creates lubrication problems, which in turn leads to mechanical breakdown. 

Baasel, W. D. and J. S. Smith, A Mathematical Solution for the Condensation of Vapors from Non-Condensing Gases in Laminar Elow Inside Vertical Cylinders, AIChE Journal, Nov. (1963) p. 826. 

Dust can be said to be a solid broken down into powder, and the form that it takes will have different effects on the body. Fibrous dusts can attack tissue directly while others may be composed of poisons, which are absorbed into the bloodstream. For the purpose of this chapter, fumes can be regarded as very small particles resulting from the chemical reaction or condensation of vapor, which can have the same two effects. It is not necessary for plant engineers to have an in-depth knowledge of pathology, only that they must be aware of the possible results of exposure to dusts and fumes. 

McNaught, J. M. (1983) An assessment of design methods for condensation of vapors from a noncondensing gas, in Heat Exchangers Theory and Practice (McGraw-Hill). 

Figure 25.8 Refrigeration is usually required for the condensation of vapor emissions.

Referring to Figure 8, temperature Tc is the chamber temperature and Ts is the surface temperature at the salt solution/vapor interface. The temperature of the chamber is well defined and is an experimental variable, whereas Ts must be higher than Tc due to condensation of vapor on the saturated solution surface. We can determine Ts by applying the Clausius-Clapeyron equation to the problem. Assume that the vapor pressures of the surface and chamber are equal (no pressure gradients), indicating that the temperature must be raised at the surface (to adjust the vapor pressure lowering of the saturated solution) to Pc (at Tc) = Ps (at Tc). However, there is a difference in relative humidity between the surface and the chamber, where RHC is the relative humidity in the chamber and RH0 is the relative humidity of the saturated salt solution, and we obtain... 

Fujikawa S, Akamatsu T (1980) Effects of the nonequilibrium condensation of vapor on the pressure wave produced by the collapse of a bubble in a liquid. J Fluid Mech 97 481-512... 

Selective Condensation of Vaporized Organophosphorus Ligand. Certain phosphorus ligands have sufficient volatility that portions may be volatilized when aldehyde and higher boiling aldehyde condensation byproducts are separated from the catalyst solution in, for example, a liquid recycle vaporizer. The phosphorus ligand may be condensed, recovered and returned to the catalyst solution [35] according to the procedure disclosed in US 5,110,990. 

Combined light diffraction and interference on hierarchical nanostructures Combined action of adsorption and capillary condensation of vapors in the domains of ordered hierarchical nanostructures 19... 

Condensation of vapors or cooling of hot gases. For example, steam is commonly used to clean vessels and, less frequently, to create an inert atmosphere inside of equipment. Steam condensing inside a closed vessel can create a significant vacuum, and vessels (e.g., railcars) have collapsed when all vessel inlets were... 

Nucleation. As explained in Section III.6, small droplets have a higher vapor pressure than plane surfaces of an identical composition at an identical temperature. The difference between the two pressures is given by Eq. (63). This effect renders condensation of vapors more difficult than it would have been at 7 = 0. 

In the case of simple amphiphiles (fatty acids, fatty alcohols, lecithins, etc.), in several cases, transition phenomena have been observed between the gaseous and coherent states of films, which show a very striking resemblance to the condensation of vapors to liquids in three-dimensional systems. The liquid films shows various states in the case of some amphiphiles, as shown in Figure 4.6 (schematic). In fact, if the II versus A data deviate from the ideal equation, then the following interactions may be expected in the film ... 

The gas ballast facility (see Fig. 2.13) prevents condensation of vapors in the pump chamber of the pump. When pumping vapors these may only be compressed up to their saturation vapor pressure at the temperature of the pump. If pumping water vapor, for example, at a pump temperature of 70 °C, the vapor may only be compressed to 312 mbar (saturation vapor pressure of water at 70 °C (see Table XIII In Section 9)). When compressing further, the water vapor condenses without Increasing the... 

Two basic processes are used to create smoke clouds the condensation of vaporized material and the dispersion of solid or liquid particles. Materials can either be released slowly via a pyrotechnic reaction or they can instantaneously be scattered using an explosive material. Technically, a dispersion of fine solid particles in air is termed a smoke, while liquid particles in air create a fog. A smoke is created by particles in the 10 -10 " meter range, while larger suspended particles create a dust (1). ... 

Stack sampling is not sufficient for characterizing all sources and may not be the best method even for ducted point sources. Because of condensation of vapors, fallout of very large particles and the neglect of non-ducted emissions, the materials collected from stacks, especially those at high temperatures, will often not represent the particles from the source observed at a receptor several kilometers away. 

Finally, corrosion of internal metal surfaces, constituents of the absorbing and water-conditioning agents, and condensation of vapor components further contribute to the concentrations of Cr and Mn, Ca and P, and Se and S in the scrubbing solution and lead to their enrichment in fine aerosol emissions. 

There are a number of techniques for generating aerosols, and these are discussed in detail in the LBL report (1979) and in volumes edited by Willeke (1980) and Liu et al. (1984). We briefly review here the major methods currently in use these include atomizers and nebulizers, vibrating orifices, spinning disks, the electrical mobility analyzer discussed earlier, dry powder dispersion, tube furnaces, and condensation of vapors from the gas phase. 

Fully Encapsulating Suit (FES) Sometimes referred to as a Moon Suit, personal protective clothing diat provides complete skin, eye, and respiratory proteetion, and includes positive-pressure SCBA. The reader should refer to Chapter 2 for detailed discussions. Refer to Protective Materials. Fumes Solid particles formed by the condensation of vaporized solids, usually molten metals. Particles are much smaller than dusts with typical size ranges between 0.01 and 1.0 microns. Functional Group An atom or group of atoms, bound together chemically, that has an unpaired electron, which when it attaches itself to the hydrocarbon backbone, imparts special properties to the new compound thus formed. 

The Greek word y was used also for the dome-shaped receiver of glass placed over distilling apparatus to act as a condenser of vapors. See Borthclot, Introduction, pp. 132-134. The word thus conveys a double sense, a popular and a technical concept. 

Lightfoot (L5, L6) considered the solidification of a semi-infinite steel mass in contact with a semi-infinite steel mold, where the thermal properties of the phases were taken to be identical. In a later paper, (L7) different thermal constants for the liquid and solid metal and for the mold were assumed. With uniform initial phase temperatures, it is seen that all boundaries of the system are immobilized in jj-space. Yang (Y2) rederived this result and further extended the application of the similarity transformation to three-region problems with induced motion. An example is the condensation of vapor, as a result of sudden pressurization, in a tank with relatively thick walls. 

The detector and injector temperatures should be maintained about 10° above the column temperature. This ensures against condensation of vapor and causes rapid vaporization of the sample upon injection. 

DEPHLEGMATION. Partial condensation of vapor from a distillation operation to produce a liquid richer in higher-boiling constituents than the original vapor. The residual vapor is richer in the lower boiling constituents. 

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