Entrainment calculation

Bubble caps at outlet side blowing liquid into downcomer limiting capacity. At high rates, separation was reduced as in entrainment. Calculations indicated this should not happen. Scan indicated problem. Debottlenecking activity. 

The performance of a reactor for a gas-solid reaction (A(g) + bB(s) -> products) is to be analyzed based on the following model solids in BMF, uniform gas composition, and no overhead loss of solid as a result of entrainment. Calculate the fractional conversion of B (fB) based on the following information and assumptions T = 800 K, pA = 2 bar the particles are cylindrical with a radius of 0.5 mm from a batch-reactor study, the time for 100% conversion of 2-mm particles is 40 min at 600 K and pA = 1 bar. Compare results for /b assuming (a) gas-film (mass-transfer) control (b) surface-reaction control and (c) ash-layer diffusion control. The solid flow rate is 1000 kg min-1, and the solid holdup (WB) in the reactor is 20,000 kg. Assume also that the SCM is valid, and the surface reaction is first-order with respect to A. 

X Parameter used in liquid entrainment calculation, defined by Eq,... 

Duration and rate of transfer into the tank. The quantity of petrol that overflowed Tank 912 at Buncefieid from initial overflow to ignition was approximately 300 tonnes. If the transfer rate or overflow duration is estimated to be significantly different to that at Buncefieid, then this may affect the formation and size of the cloud. An estimate of cloud generation could be made based on modelling such as the HSL entrainment calculator and a 2 m cloud height (for further information see Appendix 1). 

Entrainment Above TDH. A relatively simple procedure to calculate the amount of entrainment above the TDH is given hereia. A more detailed treatment can be found ia Reference 21. 

Flue particles ia a fluidized bed are analogous to volatile molecules ia a Foiling solution. Therefore, the concentration of particles ia the gas above a fluidized bed is a function of the saturation capacity of the gas. To calculate the entrainment rate, it is first necessary to determine what particle sizes ia the bed can be entrained. These particles are the ones which have a terminal velocity less than the superficial gas velocity, assuming that iaterparticle forces ia a dilute zone of the freeboard are negligible. An average particle size of the entrainable particles is then calculated. If all particles ia the bed are entrainable, the entrained material has the same size distribution as the bed material. 

Figure 18 is an entrainment or gas-carryiag capacity chart (25). The operating conditions and particle properties determine the vertical axis the entrainment is read off the dimensionless horizontal axis. For entrainment purposes, the particle density effect is considered through the ratio of the particle density to the density of water. When the entrainable particle-size distribution is smaller than the particle-size distribution of the bed, the entrainment is reduced by the fraction entrainable, ie, the calculated entrainment rate from Figure 18 is multipfled by the weight fraction entrainable. 

Entrainment of Particles in an Air Stream. The lighter the particle and the finer its size, the longer it may remain suspended in an airstream such as upon filling of a bin. Secondary air currents can carry airborne particles away from a fill point into outer areas of a bin, scattering them in a way that bears no resemblance to the calculated trajectory. 

Overall Column Efficiency Calculated values of E, , must be corrected for entrainment, if any, by the Colburn equation [Eq. (14-101)]. The resiJting corrected efficiency is then converted to column efficiency by the relationship of Lewis [Ind. Eng. Chem., 28, 399 (1936)] ... 

Two wooden beams are butt-jointed using an epoxy adhesive (Fig. A1.3). The adhesive was stirred before application, entraining air bubbles which, under pressure in forming the joint, deform to flat, penny-shaped discs of diameter 2fl = 2 mm. If the beam has the dimensions shown, and epoxy has a fracture toughness of 0.5 MN mT , calculate the maximum load F that the beam can support. Assume K = cT Tra for the disc-shaped bubbles. 

The Souders-Brown correlation considers entrainment as the controlling factor. For high liquid loading situations and final design, complete tray hydraulic calculations are required. 

For vaporAiquid separators there is often a liquid residence (holdup) time required for process surge. Tables 1, 2, and 3 give various rules of thumb for approximate work. The vessel design method in this chapter under the Vapor/Liquid Calculation Method heading blends the required liquid surge with the required vapor space to obtain the total separator volume. Finally, a check is made to see if the provided liquid surge allow s time for any entrained water to settle. 

Another important consideration in tower design is tray downcomers size. At high ratios of liquid flow to vapor flow a proportionally greater area on the tray must be allotted to the downcomer channel opening. Downcomers are designed from basic hydraulic calculations. If the downcomer is inadequately sized and becomes filled with liquid, liquid level will build on the tray above. This unstable situation will propagate its way up to the tower and result in a flooded tower condition. Excessive entrainment can also lead to this same condition and, in fact, is usually the cause of flooding. 

GASFLOW models geometrically complex containments, buildings, and ventilation systems with multiple compartments and internal structures. It calculates gas and aerosol behavior of low-speed buoyancy driven flows, diffusion-dominated flows, and turbulent flows dunng deflagrations. It models condensation in the bulk fluid regions heat transfer to wall and internal stmetures by convection, radiation, and condensation chemical kinetics of combustion of hydrogen or hydrocarbon.s fluid turbulence and the transport, deposition, and entrainment of discrete particles. 

EXP AC analyzes an interconnected network of building rooms and ventilation systems. A lumped-parameter formulation is used that includes the effects of inertial and choking flow in rapid gas transienl.s. The latest version is specifically suited to calculation of the detailed effects of explosions in the far field using a parametric representation of the explosive event. A material transport capability models the effects of convection, depletion, entrainment, and filtration of... 

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