Flowrate selectivity

The data generated via the round robin testing program is analyzed for each of the flowrates selected and for each of the meter positions. For each of these conditions, plots are produced of the respective meter performance characteristics— i.e., meter factor, discharge coefficient, etc., see [5, 6], Individual results, or averages thereof can be plotted. Each point represents the combined resnlts for both meters for each laboratoiy. 

The reactor feed may be preheated and the feed pressure may alter. The volumetric flowrate of gases depends on the reactor temperature and pressure at fixed mass flowrate. In many cases, the feed is liquid at room temperature, while the reaction mixture is a gas at the higher temperature in the reactor. In these instances, the performance of the reactor is represented as conversion and selectivity against the liquid hourly space velocity (LHSV). This is defined as... 

The column diameter is normally determined by selecting a superficial velocity for one (or both) of the phases. This velocity is intended to ensure proper mixing while avoiding hydrodynamic problems such as flooding, weeping, or entrainment. Once a superficial velocity is determined, the cross-sectional area of the column is obtained by dividing the volumetric flowrate by the velocity. 

Let us revisit the depbenolization problem described in Sections 3.2 and 6.3. The objective is to synthesize a MOC-MEN with the least number of units. First, CID (Fig. 6.3) and the tables of exchangeable loads TEL (Tables 6.7 and 6.8) are developed based on the MOC solution identified in Sections 3.2 and 6.3. Since neither S4 nor S5 were selected as part of the MCX2 solution, there is no need to include them. Furthermore, since the optimal flowrates of S, S2 and S3 have been determined, the TEL for the MSAs can now be developed with the total loads of MSAs and not per kg of each MSA. 

Fig. 3-8. HPLC evaluation of a 250 x 4.6 mm i.d. analytical column packed with the selected dipep-tidic (5)-Glu-(5)-Leu-DNB CSP. Conditions mobile phase 20 % 2-propanol in hexane, flowrate 2.0 mL min, UV detection at 280 nm. (Reprinted with permission from ref. [86]. Copyright 1999, American Chemical Society.)...

Fig. 3-18. Selectivity factors a determined for (3,5-dinitroben-zoyl)leucine diallylamide on CSP 15-24. Conditions analyte (3,5-dinitrobenzoyl)leucine diallylamide column 150 x 4.6 mm i.d. mobile phase 20 % hexane in dichloromethane flowrate 1 mL min f UV detection at 254 nm.

In this mode, the solid is no longer moving. The shifting of the inlet and outlet lines only simulates solid flow, and the solid flowrate downward is directly linked to the shift period. Proper selection of flowrates is required to stabilize the different fronts of species A and B in the proper zones. The adequate choice of the flowrates requires a minimum knowledge of the physico-chemical properties of the system. The influence of adsorption isotherms and plate numbers is simulated by the software. 

The efficiency of many CSPs increases dramatically when liquid eluents are replaced with sub- or supercritical fluids. During a comparison of LC and SFC performed with a Chiralcel OD CSP, Lynam and Nicolas reported that the number of theoretical plates obtained was three to five times higher in SFC than in LC [26]. The separation of metoprolol enantiomers by LC and SFC on a Chiralcel OD CSP is illustrated in Fig. 12-2. Although impressive selectivity is achieved by both techniques, resolution is higher in SFC (R = 12.7) than in LC (R = 4.8), and the higher flowrate in SFC reduces the analysis time. The increased efficiency of SFC also improves peak symmetry. 

The component with the lowest equilibrium constant is called the key component in the stripping process, because it yields the largest value of Vnjm- This largest value is the true minimum air flowrate, whereas the actual air flowrate should be selected at 1.20 to 2.0 times the minimum. This becomes a balance between fewer theoretical stages at actual air flowrate, yet requires a larger diameter column to carry out the operation. 

Factors Affecting Drilling Rates 1090. Selection of Weight on Bit, Rotary Speed, and Drilling Time 1091. Selection of Optimal Nozzle Size and Mud Flowrate 1097. 

Once the governing minimum air volumetric flowrate has been found for an interval to be drilled, the compressors of fixed volumetric flowrate can be selected. An additional compressor is usually on site as a stand-by to have additional air available in case of unexpected downhole problems and to have a compressor available in the event one of the operational compressors needs to be shut down for maintenance. 

The number of fixed volumetric flowrate compressors is selected such that the necessary minimum air volumetric flowrate is exceeded. The air volumetric flowrate that the compressors produce is shown as the real air volumetric flowrate. This real air volumetric flowrate, (actual cfm) is used to calculate the bottomhole pressure. Bottomhole pressure, (Ib/fi abs) is determined by... 

For straight hole drilling the turbine motor with the highest possible torque and the lowest possible speed is of most use. Thus the turbine motor is selected such that the motor produces the maximum amount of power for the lowest possible circulation flowrate (i.e., lowest speed). The high power increases rate of penetration and the lower speed increases bit life particularly if roller rock bits are used. 

The constant coefficient for float C arises from turbulence promotion, and for this reason the coefficient is also substantially independent of the fluid viscosity. The meter can be made relatively insensitive to changes in the density of the fluid by selection of the density of the float, pf. Thus the flowrate for a given meter will be independent of p when dG/dp = 0. 

Figure 9.21. (a) Dependence of selectivity on C2H2 conversion for various catalyst potentials. The behaviour is compared with this of BASF catalysts (b) Dependence of C2H2 conversion (closed symbols, solid lines) and selectivity (open symbols, dashed lines) on flowrate and GHSV for various catalyst potentials. 3-pellet configuration.30 Reprinted with permission from the Institute for Ionics. 

Figure 5. Effect of adsorbent mass in the molecular sieve trap on the ethylene, ethane and total C2 selectivity at a fixed methane conversion of 15%. Recirculation flowrate 220 cm3 STP/min...

Figure 6. Continuous flow steady-state operation (a) Effect of oxygen stream flowrate on C2 selectivity and yield (b) corresponding effect of methane conversion on the selectivity and yield of C2H4 and C2He Catalyst Sr/LaaOa T=750°C recirculation flowrate 200 cm3/min.

Temperature variation may also be a relevant factor in flowrate stability. Since the viscosity of the solvent is temperature dependent, wide swings in the ambient temperature can directly affect pump performance. The direct effects of temperature on pump performance usually are far smaller, however, than the effects on retention and selectivity therefore, control of column temperature is generally sufficient to obtain high reproducibility. 

Reactor Selectivity (%) Yield (%) Flowrate of chlorine (kmols-1) Volume (m3)... 

The feed composition and flowrate to the distillation are usually specified. Also, the specifications of the products are usually known, although there may be some uncertainty in product specifications. The product specifications may be expressed in terms of product purities or recoveries of certain components. The operating parameters to be selected by the designer include ... 

The flux, and hence the permeance and permeability, can be defined on the basis of volume, mass or molar flowrates. The accurate prediction of permeabilities is generally not possible and experimental values must be used. Permeability generally increases with increasing temperature. Taking a ratio of two permeabilities defines an ideal separation factor or selectivity awhich is defined as ... 

Example 25.5 A gas turbine exhaust is currently operating with a flowrate of 41.6 kg s-1 and a temperature of 180°C after a heat recovery steam generator. The exhaust contains 200 ppmv NOx to be reduced to 60 rng rn 3 (expressed as N02) at 0°C and 1 atm. The NOx is to be treated in the exhaust using low temperature selective catalytic reduction. Ammonia slippage must be restricted to be less than 10 mgm 3, but a design basis of 5 mg-rn 3 will be taken. Aqueous ammonia is to be used at a cost of 300 -1 1 (dry NH3 basis). Estimate the cost of ammonia if the plant operates... 

S Entropy (kJ-K-1, kJkg-1-K-1, kJkmol-1-K-1), or number of streams in a heat exchanger network (-), or reactor selectivity (-), or reboil ratio for distillation (-), or selectivity of a reaction (-), or slack variable in optimization (units depend on application), or solvent flowrate (kg s-1, kmol-s-1), or stripping factor in absorption (-)... 

The next two steps after the development of a mathematical process model and before its implementation to "real life" applications, are to handle the numerical solution of the model s ode s and to estimate some unknown parameters. The computer program which handles the numerical solution of the present model has been written in a very general way. After inputing concentrations, flowrate data and reaction operating conditions, the user has the options to select from a variety of different modes of reactor operation (batch, semi-batch, single continuous, continuous train, CSTR-tube) or reactor startup conditions (seeded, unseeded, full or half-full of water or emulsion recipe and empty). Then, IMSL subroutine DCEAR handles the numerical integration of the ode s. Parameter estimation of the only two unknown parameters e and Dw has been described and is further discussed in (32). 

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