Flowrate scaling

As the usual parabolic velocity profile of pressure-driven Poiseuille flow leads to the flowrate scaling as R whereas the fiat velocity profile obtained in pure electroosmotic flow gives rise to a flowrate that scales as R, it can be seen that it is more efficient to drive microchannel flows where R becomes very small using electrokinetic flows as opposed to pressure-driven flow. However, there are some design issues to be considered in electrokinetic bubble transport. 

Filtration experiments are typically conducted in pilot scale equipment and generally tests are conducted either at constant pressure or constant rate to determine axo, as well as s and Rf, for a given sludge and filter medium. Such tests provide empirical information that will enable the time required tor the pressure drop to reach the desired level for a specified set of operating conditions to be determined. In the initial stages of filtration, the filter medium has no cake. Furthermore, Ap is not zero, but has a value that is a function of the resistance of the medium for a given flowrate. This initial condition can be stated as ... 

The PHI-TEC or VSP bench scale apparatus can be employed to determine information about the self-heat rate and vapor disengagement when this is not readily available. Additionally, the VSP equipment can be used for flashing flow characteristics using a special bottom vented test cell. Here, the flowrate, Gq (kg/sm ), is measured... 

Interpreting results of the pinch diagram As can be seen from Fig. 3.12, the pinch is located at the corresponding mole fractions (y,Xi.jc ) - (0.(K)10, 0.0030, 0.0010). The excess capacity of the process MSAs is 1.4 x lO" kg mol benzene/s and cannot be used because of thermodynamic and practical-feasibility limitations. This excess can be eliminated by reducing the outlet compositions and/or flowrates of the process MSAs. Since the inlet composition of S2 corresponds to a mole fraction of 0.0015 on the y scale, the waste load immediately... 

It is worth pointing out that the wide range of coefficients may cause computational problems for the optimization software. This is commonly referred to as the scaling problem. One way of circumventing this problem is to define scaled flowrates of MSAs in units of 10 ° m /s and scaled residual loads in units of 10 ° kmol/s, i.e., let... 

Step 3 The 1,000-lb/h flowrate projected diagonally up from the bottom scale. 

Positive Displacement Motor Performance. Using the positive displacement motor performance data in Table 4-114 and the scaling relationships in Equations 4-168 through 4-170, the performance graph for the positive displacement motor operating with a circulation flowrate of 348 gal/min can be prepared. This is given in Figure 4-213. 

In a series of experiments on the flow of flocculated kaolin suspensions in laboratory and industrial scale pipelines(26-27-2Sl, measurements of pressure drop were made as a function of flowrate. Results were obtained using a laboratory capillary-tube viscometer, and pipelines of 42 mm and 205 mm diameter arranged in a recirculating loop. The rheology of all of the suspensions was described by the power-law model with a power law index less than unity, that is they were all shear-thinning. The behaviour in the laminar region can be described by the equation ... 

Control rule-1. To achieve fermention of excellent quality, keep (a) the agitation rate in the first scaling episode (growth phase) > 37 units and (b) the duration of the first episode in the air flowrate < 25 h. 

Ethyl formate is to be produced from ethanol and formic acid in a continuous flow tubular reactor operated at a constant temperature of 303 K (30°C). The reactants will be fed to the reactor in the proportions 1 mole HCOOH 5 moles C2H5OH at a combined flowrate of 0.0002 m3/s (0.72 m3/h). The reaction will be catalysed by a small amount of sulphuric acid. At the temperature, mole ratio, and catalyst concentration to be used, the rate equation determined from small-scale batch experiments has been found to be ... 

When a pilot-scale fermenter is run in continuous mode with a fresh feed flowrate of 65 1/h, the effluent from the fermenter contains 12 mg/1 of the original substrate. The same fermenter is then connected to a settler-thickener which has the ability to concentrate the biomass in the effluent from the tank by a factor of 3.2, and from this a recycle stream of concentrated biomass is set up. The flowrate of this stream is 40 1/h and the fresh feed flowrate is at the same time increased to 100 1/h. Assuming that the microbial system follows Monod kinetics, calculate the concentration of the final clarified liquid effluent from the system. /x, = 0.15 h-1 and Ks = 95 mg/1. 

A processing plant is a physical system containing a large number of units and streams. For example, counting the equipment in the processing section as well as in the service section (considering mixers and stream dividers) of a petrochemical plant reveals the existence of approximately 1000 interconnected units and about 2500 streams. If we also take into account that in each stream the variables of interest can be flowrate, composition, temperature, pressure, and enthalpy, it is evident that data treatment in a typical plant involves the solution of a large-scale problem. 

The design flowrate of the pilot-scale test system is 10 gph or 900 L/day, which is adequate for small quantity generators, or a slip stream from a higher capacity operation could be used. Once onsite testing is completed, the system may be transported to an operating facility for demonstration testing. The test system will be constructed in four modules to simplify transportation. When the modules are prepared for shipment, only Interconnected piping will need to be separated and capped. 

Automatic flow controllers have recently become available which operate in the 1-100 cm3/min flow range. These are voltage settable such that thumb wheels switches or potentiometers can be used to set the flowrate. These are specified at a repeatability of setpoint of about 0.2% and an accuracy of 1-2% of full scale. These flow controllers can easily be adapted to give a flow readout. The price of these units is still quite high at about ( 500 - 600) per channel but all indications are that they will be more widely used in the future. Typical specifications for three such devices are given in Table 6.4. 

Note that the above expressions are nonlinear due to the bilinear terms between the temperatures and the flowrates. They are also scaled by 1000. 

The pilot plant scale experimental unit, Fig. 2, described in previous papers [2,3] is provided with a blower that supplies a maximum air flowrate of 300Nm3/h at a pressure of 1500 mm of water column. The flow measurement is carried out with two rotameters, used in the ranges from 2.5 to 30 and from 30 to 250 Nm3/h. In the range from 0 to 4 Nm3/h a gas volume meter provided with paddles is used. A system of valves allows for choosing the suitable rotameter for the desired flowrate. This flowrate is fixed by closing or opening a butterfly valve. 

Now suppose that we design a plant-scale reactor that is 1000 times larger in volume (19 m3). The feed flowrate is 1000 times larger (3.506 kg/s), and the required heat transfer is 1000 times larger (817 kW). 

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