Flow rale

Derive expressions for the velocity profile, shear stress, shear rate and volume flow rale during the isothermal flow of a power law fluid in a rectangular section slit of width W, depth H and length L. During tests on such a section the following data was obtained. 

Chapter 4. Cycle efficiency with turbine cooling (cooling flow rales specifled)... 

Makeup water flow rale = 63 gpm Control valve is 25 percent open... 

To illustrate the disturbance rejection effect, consider the distillation column reboiler shown in Fig. 8.2a. Suppose the steam supply pressure increases. The pressure drop over the control valve will be larger, so the steam flow rale will increase. With the single-loop temperature controller, no correction will be made until the higher steam flow rate increases the vapor boilup and the higher vapor rate begins to raise the temperature on tray 5. Thus the whole system is disturbed by a supply-steam pressure change. 

Hold the recycle toluene flow rale constant by adjusting fuel to the furnace. 

At the beginning of the batch cycle, both the reactor liquid and the jacket water are at 203°F. At this point in lime, catalyst is added to the reactor and a reaction occurs which generates heat at a constant rate of 15,300 Btu/min. At this same moment in time, makeup cooling water at 68°F is fed into the jacket at a constant 832 lb ,/min flow rale. 

Modify your feedforward controller design of Prob. 11.10 so that it can handle both feed temperature and feed flow rale changes and uses a feedback temperature controller to trim up the steam flow. 

D[-., be available in a range of sires such that the polymer (or molecule) of diameter, D, can pass through the large holes freely or the small holes with some difficulty. Both the pressure drop across the membrane and the concentration of effluent are measured continuously while the flow rales of effluent are increased in step-wise or continuous fashion. At this stage of development only the unconfined time-average radius of gyration is considered as k However other viscometric or projection radii may ultimately be more useful. 

The flow rale of water entering a given mini- or discrete body ol workings A collective term for (lie eoids belonging to a particular mine... 

Fig. 4. Temporal variations in isotopic composition and gas/steam ratio (G/S) monitored in two wells (Wl, W2) of the central area in the Larderello geothermal field, located near the re-injection welt. Undisturbed pre-injection values (first point of each series, shown as large open circle) and flow rale of injected water (0 are also shown. I, II and III refer to the three re-injection periods considered.

Table 1 lists the operating conditions, crude and gas flow rales, and crude residence times for the Ninian and Brent separators. 

While the tower diameter must be designed to process the maximum expected liquid flow rate, it must also be designed to handle the maximum expected gas flow rale The superficial gas mass flow rate is also critical to the tower diameter selected and is defined in Eq 2 in terms of the gas flow rate, gas density, and tower cross-scctional area. 

Dia (refer Area Flow Bale Flow Rale... 

Factors That Influence Performance. The oil-removal efficiency of the deoiling liquid/liquid hydrocyclooe is influenced by a number of factors, some of which currently arc not fully defined or understood. It is certain, however, that the inlet flow rale, reject rate, droplet size, oil concentration, differential specific gravity, and temperature play significant roles. This can be represented siraplisti-cally by the following approximation ... 

Control. The control scheme for a hydrocyclone installation in which wc have identified flow rale as a key parameter would logically be based on total flow rate with a ratio device adjusting a flow-control valve in the reject line to maintain the desired reject ratio. However, problems can be expected with an installation based on flow/ratio control because of gas breakout, which exists preferentially with the reject stream and creates two-phase flow. Normal metering devices will not tolerate two-phase flow and give sufficiently accurate and reproducible results for control purposes. 

The next step was to determine efficiency as a function of reject ratio while holding the inlet flow rale approximately constant. A series of runs has been completed with reject ratios in the range of 0.1 to 17.0%. 

Having determined the optimum reject ratio, the next stage was to vary the flow rale to determine its impact on efficiency while holding the reject ratio approximately constant. Runs have been carried out with individual unit flow rates ranging from 288 to 1244 m3/d water (1,812 to 7,826 BWPD]. Results indicate that performance falls off at flow rates below 318 m3/d water (2.000 BWPD) per unit and on the upper end with flow rates above 1113 m3/d water (7,000 BWPD per unit. Fig. 3 illustrates graphically the trend of efficiency vs. flow rate. The scatter in results is considered to be caused primarily by variations in both inlet concentration and the reject rate. 

Row-rate trials have been carried out from 111 to 684 m3/d water (700 to 4,300 BWPD] for a single 60-mm [2 4-in ] unit with about a 1200-kPa [174-psi] driving force. Efficiency starts to fall off at flow rates less than 159 m3/d water [1,000 BWPD] on the low end of the flow rate curve, again because there is insufficient flow lo support the vortex motion. It is also worth noting that the minimum flow rale threshold for the 60-mm [2.4-in.] cyclone is... 

Ditaiant. llic initial flow of a dilatant substance under a low shear stress is at a high rale further increases in shear stress result in a lov er flow rale. A dilatant substance is sometimes called an inverted plastic or inverted pscudoplastic. 

C( = ntlK or ni(V concentration n, = mots of component i in the reactor rtj = molal flow rale of component /... 

Elution fast Decrease flow rale or - Decrease AcOH or Both... 

The dimensionless variables and parameters are axial coordinate 0 < < 1, conversion temperature 0(1 ), recycle flow rale f and reactor-inlet concentration z3 plant Damkohler number Da, activation energy y, adiabatic temperature rise B, heat-transfer capacity p, coolant temperature 0 concentration of recycle and product streams z3, z4. For convenience, X = x(l) will stand for conversion at reactor outlet. 

Two structure insensitive reactions have been selected cyclohexene hydrogenation [6] oil surface Pt sites upon silica and but-l-ene isomerisation on acidic sites in bentonite. Both reactions were studied in differential reactors The former was investigated at 273-313K and lOlkPa Samples (5-lGmg) of catalyst were flushed with N2, pre-reduced in H at 423K for lh, flushed with N2 and then the reactant stream (lOlkPa total pressure cyclohexene N2 H2 = 1,7 89.5 10 1 200cm3.min 1 total flow rale) was introduced and analysed... 

Whereas for bubbling fluidized beds the solids holdup in the upper part of the reactor and the entrainment of catalyst are often negligible, these features become most important in the case of circulating fluidized beds These systems are operated at gas velocities above the terminal settling velocity ux of a major fraction or even all of the catalyst particles used (% 1 m s 1 < umass flow rales to be externally recirculated are high, up to figures of more than 1000 kg m 2s-1... 

The final step in the preparation of a catalyst is the transformation of the precursor to the active phase (e.g. metal, sulfide) which is sometimes called activation. The activation may be a reduction (e.g. by H2), reduction-sulfidation (e.g. by H2 + H2S), dehydroxyla-tion (e.g. by removal of H20 from zeolite) or oxidation (e.g. by O2). The details of the activation process must be stated (e.g. partial pressure and purity of gas, method of heating and its rate, gas reacting flow rale, sample size). 

Fig. 7. Methane conversion, CO selectivity, and oxygen flux through the ceramic membrane during the partial oxidation of methane in a ceramic membrane reactOT (see Fig. 6). Reaction conditions temperature, 1148 K catalyst, 3(X) mg of LiLaNi0 7-Al2Q3 air flow rale, 3(X) mL min (NTP) feed gas molar ratio, CH4/He = 1/1 feed flow rate, 42.8 mLmin (NTP) (72).

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