Solids deposition

Vane [Line Separator) 1. High Efficiency 2. Good turndown characteristics 3. Relatively inexpensive k. Low pressure drop-typIcal ly less than. 5 psi 1. Liquid loading Is limited to roughly 5-lot of gas mass flow rate 2. Pockets can plug with solids 3. Difficult to clean unless vanes are removable 

Vane (Vertical Gas Separator) 1. Better efficiency than line separator 2. Good turndown characteristics 3. Will separate liquid slugs k. Will Operate efficiently with hlqh liquid loadino 1. Pockets and drain piping can plug with sol Ids 2. Difficult to clean unless vanes are removable 3. Relatively expensive 

Hash Separator 1. Generally good efficiency at low pressure 2. Inexpensive if Installed In existing vessel 3. Available In a variety of materials k. Very low pressure drop less than one Inch water 1. Very susceptible to plugging 2. Expensive If new tank Is needed to house mesh pad 3. Highly susceptible to corrosion 

Karbate Separator 1. High efficiency 2. Good turndown characteristics 3 Vary low pressure drop-lass than one Inch water 1. Only available In Karbate 2. Liquid loading limited 3. Somewhat difficult to clean I). A trap device Is needed for 1 Iquid col lection 

Cantrtfugai (Line) 1. Inexpensive 1. Lower efficiency than vane line separators 2. A trap device Is needed for liquid collection 3. Limited liquid handling capacity 

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Cooling water systems are dosed with corrosion inhibitors, polymers to prevent solid deposition, and biocides to prevent the growth of microorganisms. 

The Octane Requirement Increase, ORI, is a phenomenon manifested by the appearance of knocking and is due to the increase in engine octane demand with time. This phenomenon is correlated with the increase of solid deposits in the combustion chamber. Although the causes have not been determined with certainty, some companies have patented additives which modify the deposits. The effect is to limit the increase in octane demand (Bert et al., 1983 Chevron, 1988 Nelson et al., 1989). 

Finally, it has been possible to obtain LEED patterns from films of molecular solids deposited on a metal-backing. Examples include ice and naphthalene [80] and various phthalocyanines [81]. (The metal backing helps to prevent surface charging.)... 

Globe valves in horizontal lines prevent complete drainage. Seat-wiper valves in which the disk may be rotateci by a separate stem inside and concentric with the main stem are used to clear the seats of solid deposits. 

Although surface-cooled types of MSMPR crystalhzers are available, most users prefer crystallizers employing vaporization of solvents or of refrigerants. The primary reason for this preference is that heat transferred through the critical supersaturating step is through a boil-ing-hquid-gas surface, avoiding the troublesome solid deposits that can form on a metal heat-transfer surface. 

Blockage of piping, valves or flame arresters due to solid deposition. Potential for system overpressure. 

Install insulation/tracing of piping to minimize solid deposition (freezing/precipitation)... 

Recirculate material in lines prone to solid deposition... 

Ignition of condensed flammable vapor or solid deposits in ductwork/ piping. Possibility of fire/explosion. 

Blockage of relief device by solids deposition (polymerization, solidification). Possible loss of overpressure protection. 

Filter cake resistance (Rq) is the resistance to filtrate flow per unit area of filtration. R increases with increasing cake thickness during filtration. At any instant, Rc depends on the mass of solids deposited on the filter plate as a result of the passage of V (m ) filtrate. Rf may be assumed a constant. To determine the relationship between volume and residence time t. Equation 5 must be integrated, which means that Rc must be expressed in terms of V. 

To avoid injuries of this sort, we should use protective hoods or helmets when breaking joints on lines likely to contain corrosive liquids trapped under pressure, either because the pressure cannot be blown off through a valve or because lines may contain solid deposits. 

Saturated fats in the diet pose a much greater health risk than unsaturated fats because they are much more likely to lead to solid deposits on blood vessels. 

These are semisolid or solid substances formed in nature from crude oils after the volatile components have evaporated and the remainder has undergone oxidation and polymerization. They are also referred to as bitumens, waxes, and pitch. These materials are believed to consist of mixtures of complex organic molecules of high molecular weight. As with crude oils, which contain thousands of different chemical compounds, an exact chemical analysis for identification and composition is impractical to perform on the solid deposits of petroleum. 

Since the filter resistance in the filter medium is neglected, the second part of equation (7.3.1.5) is neglected. Let us define a new constant, C, equal to the mass of solid deposited on the filter per volume of filtrate. 

The general theory was worked out by Roozeboom (Zeitschr. physik. Chem., 1899) from the standpoint of the theory of thermodynamic potential. The equations (2a, h), (3a, h) of the preceding section apply equally well to the present case, and details need not be given here. The liquid solidifies at a constant temperature when it has the same composition as the solid deposited— the so-called eutectic point. 

The highest possible quality of water should be used for nondrainable superheaters and reheaters to prevent the risk of solids deposition in the units. 

Some ionic compounds are soluble, others are not. Consider what happens when we pour a solution of sodium chloride (a strong electrolyte) into a solution of silver nitrate (another strong electrolyte). A solution of sodium chloride contains Na+ cations and Cl anions. Similarly, a solution of silver nitrate, AgNO, contains Ag+ cations and NO, anions. When we mix these two aqueous solutions, a white precipitate, a cloudy, finely divided solid deposit, forms immediately. Analysis shows that the precipitate is silver chloride, AgCl, an insoluble white solid. The... 

If we were to place a piece of zinc metal into an aqueous copper(II) sulfate solution, we would see a layer of metallic copper begin to deposit on the surface of the zinc (see Fig. K.5). If we could watch the reaction at the atomic level, we would see that, as the reaction takes place, electrons are transferred from the Zn atoms to adjacent Cu2 r ions in the solution. These electrons reduce the Cu2+ ions to Cu atoms, which stick to the surface of the zinc or form a finely divided solid deposit in the beaker. The piece of zinc slowly disappears as its atoms give up electrons and form colorless Zn2+ ions that drift off into the solution. The Gibbs free energy of the system decreases as electrons are transferred and the reaction approaches equilibrium. However, although energy is released as heat, no electrical work is done. 

Chemical vapor deposition is a synthesis process in which the chemical constituents react in the vapor phase near or on a heated substrate to form a solid deposit. The CVD technology combines several scientific and engineering disciplines including thermodynamics, plasma physics, kinetics, fluid dynamics, and of course chemistry. In this chapter, the fundamental aspects of these disciplines and their relationship will be examined as they relate to CVD. 

Chemical thermodynamics is concerned with the interrelation of various forms of energy and the transfer of energy from one chemical system to another in accordance with the first and second laws of thermodynamics. In the case of CVD, this transfer occurs when the gaseous compounds, introduced in the deposition chamber, react to form the solid deposit and by-products gases. 

The main problem of hydrate formation will arise in pipelines transporting natural gas, because gas hydrates are solids and will leave deposits. The solid deposits reduce the effective diameter of the pipeline and can therefore restrict or even clog the flow properties. Furthermore, the formation of condensates, hydrates, or ice may occur in the course of decompression of natural gas stored in natural reservoirs (e.g., in salt caverns). The operation of oil and gas pipelines in the deep sea is significantly complicated by the formation of gas hydrates [1204]. Experience indicates that large gas hydrate plugs in gas and oil pipelines form most actively during the period of an unforeseen long shut-down. In static conditions, three types of hydrate crystals can be formed [1153] ... 

In this type of machine the solids deposited on the wall of the bowl are removed by a scroll (a helical screw conveyer) which revolves at a slightly different speed from the... 

BDS process. The pore size of the filter (0.2-1.0 xm) is selected such that the liquid phase, which is miscible with the liquid that is used to wet the filter, passes through the filter, while the second liquid phase remains. Thus, an aqueous filter is wet with a liquid, which is miscible with water, but immiscible with oil. The flow rate is chosen so as to prevent solid deposition through the filter. Although, such a separation process can be applied to any oil/water emulsion, it was particularly envisioned as part of a BDS process. One may ask, whether it would be more efficient to break a macroemulsion by filtering than it is by any other means Second, in the case of microemulsions, how efficient would such a filtration process be ... 

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