Other Mass Transfer Operations in .NET

Generating QR Code in .NET Other Mass Transfer Operations

Other Mass Transfer Operations
Read QR Code 2d Barcode In Visual Studio .NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in VS .NET applications.
QR-Code Encoder In VS .NET
Using Barcode printer for Visual Studio .NET Control to generate, create QR-Code image in .NET framework applications.
Typical measurements of input variables would be from differential flowmeters and a density transmitter on the feed stream. The st eamflow measurement may require correction for static pressure. Not only does the specific volume of saturated steam change wit h pressure, but its ent halpy does too. The mass flow of st eam varies with measured differential h, and specific volume us:
Decoding Denso QR Bar Code In .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET framework applications.
Barcode Printer In .NET
Using Barcode printer for .NET framework Control to generate, create bar code image in Visual Studio .NET applications.
VoH, = K, !k!$ ,iThe ratio Ho2/v, is found to be linear with steam pressure able operating range : V,2H,2 = h,(a + bp) p over a rcason(12.20)
Barcode Recognizer In Visual Studio .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in VS .NET applications.
Painting QR Code ISO/IEC18004 In Visual C#
Using Barcode maker for .NET Control to generate, create QR Code image in .NET framework applications.
In similar fashion, the feed-flow differential hY must be compensated for density p, which additionally determines solids content:
Denso QR Bar Code Maker In .NET Framework
Using Barcode maker for ASP.NET Control to generate, create Quick Response Code image in ASP.NET applications.
QR Code 2d Barcode Printer In Visual Basic .NET
Using Barcode creator for .NET Control to generate, create QR Code JIS X 0510 image in .NET framework applications.
wg(1 - 2) = K,hip(l - 2)
Linear Creator In .NET
Using Barcode printer for Visual Studio .NET Control to generate, create Linear Barcode image in .NET framework applications.
GTIN - 12 Generation In VS .NET
Using Barcode generation for VS .NET Control to generate, create UPC-A Supplement 2 image in Visual Studio .NET applications.
Since xn is a constant,, all variables dependent on feed density can be lumped into another linear function:
Draw Code39 In .NET Framework
Using Barcode generation for VS .NET Control to generate, create Code 39 Extended image in .NET applications.
Leitcode Generator In Visual Studio .NET
Using Barcode maker for .NET Control to generate, create Leitcode image in .NET applications.
2 zz Mf cm)
Make Barcode In Visual Basic .NET
Using Barcode creator for VS .NET Control to generate, create bar code image in .NET framework applications.
Data Matrix ECC200 Printer In Visual C#.NET
Using Barcode maker for VS .NET Control to generate, create DataMatrix image in Visual Studio .NET applications.
(12.21)
Scan EAN-13 In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Bar Code Decoder In VS .NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
The complete feedforward equation for the manipulation of feed rat.e in response to steam flow is hf = WWU~ + b) f - SP (12.22)
Paint Code 39 Full ASCII In Objective-C
Using Barcode maker for iPhone Control to generate, create USS Code 39 image in iPhone applications.
Creating Code 3/9 In Java
Using Barcode creator for BIRT reports Control to generate, create USS Code 39 image in BIRT reports applications.
Coefficients a, b, 1, g, and n are all fixed; 1Z may vary somewhat. Figure 12.6 illust,ratcs how t#he feedforward control system might be designed for a multiple-effect evaporator fed from a surge tank. An
Code 128 Encoder In None
Using Barcode generation for Microsoft Excel Control to generate, create Code-128 image in Office Excel applications.
EAN / UCC - 14 Creation In VS .NET
Using Barcode creation for Reporting Service Control to generate, create GS1 128 image in Reporting Service applications.
Feed density Feed- tank level Produc densit
FIG 12.6. The feedforward system corrects for variations in feed density and steam Row.
1 Applications
average-level controller on the surge tank would set steam flow in cascade. Momentary reduction in steam availability would be accommodated by allowing the tank level to rise until the situation is corrected. In very fast evaporators of the falling-film type, where liquid holdup is minimal, feed-rate changes may reach the product before steam-rate changes do. In these applications, proper dynamic compensation requires a lag in excess of the lead time. And because of the low liquid volume, dead time is proportionately large, making feedback correction in the way of adjustments in H somewhat difficult. ;\Ianipulating a small flow of steam directly to the last effect to form a tight feedback loop has proven effective. 4 This loop should incorporate proportional and derivative modes only. Notice the similarity of this process to the oncethrough boiler, whose control system is described in Fig. 9.11. The fcedback control functions for product quality have been split into transient and steady-state components in each case.
Control of Crystallizers
A solution is saturated when an equilibrium exists between dissolved and undissolved molecules of a solute in a solvent. The concent ration of undissolved solute present as crystals does not affect the equilibrium state. The concentration of solute in solution is fixed by the equilibrium state, which varies with temperature. As a result, crystals may be deposited from solution by either of two mechanisms : 1. Evaporation of solvent 2. Reduction in solution temperature Evaporation can be caused by the application of heat or Jacuum or both, but if vacuum alone is used, the temperature of the solution is reduced along with the evaporation. A usual requirement is control over the concentration of crystals in the discharge slurry. In many cases, however, crystal size is important as well. Crystal concentration is customarily measured as density, if the cryst als are uniformly dispersed across the sensitive span of the detector. Crystal size determination unfortunately does not lend itself to on-line analysis. Figure 12.7 shows a typical cooling crystallizer. Temperature of the solution is maintained by circulating the slurry through a chiller which removes sensible heat in the feed stream and heat of fusion of the crystals. The cryst al slurry must, be kept, in mot,ion to avoid plugging. A centrifuge or filter subsequently separates the crystals and returns the mother liquor to the process. Since fine particles set#tle slowly, they accumulate at the t op of the mass
Other Mass Transfer Operations
FIG 12.7. Control of crystal content involves manipulation of mother-liquor and slurry flows.
of crystals. By withdrawing a sidestream from this region, a token amount of fine crystals can be redissolved, increasing t,he average size of the crystals remaining. Increasing the density of the slurry tends to increase crystal size by raising the level of the mass relative to the sidestream tap. Examination of the material balance across a crystallizer gives an indication of how it ought to be controlled. Mass flow of feed, F, is separated into saturated mother liquor L and crystal slurry B: F=L+B (12.23)
Weight fractions of the solute in each stream are represented by :, y, and x, respectively: Fz = Ly + B x (12.24)
Load variables are F and x; TJ is the weight fraction of solute in solution at saturation as fixed by t emperature, so it is not a variable; L and B remain to be manipulated so as to control x and the crystallizer level. Following t,he usual procedure for material-balance control, L is selected to be manipulated for density (x) control because its flow is readily measurable, whereas that of the slurry is not. Eqs. (12.23) and (12.24) are therefore solved for L, eliminating B: (12.25) Notice the similarity to the control equation for distillation-but in this
Copyright © OnBarcode.com . All rights reserved.