Concentrate flow

The recommended concentrate flow rate is a function of feed water source, as described in Chapter 9.1. The cleaner the water source, the lower the concentrate flow may be, resulting in smaller systems and lower overall cost of operation. 

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Here L is the Onsager coefficient and the minus sign (-) indicates that the concentration flow occurs from regions of high p to low p in order that the system irreversibly flows towards the equilibrium state of a... 

Process Design and Machinery. Following the field work of geologists and mining engineers and analyses (assays) to estabhsh the grades (concentrations) of values in ores, a mineral concentration flow sheet is estabhshed on the basis of a number of preliminary tests. These include studies of... 

Fig. 12. Complex copper ore concentration flow sheet. Courtesy of Denver Equipment Co.

Volumetric heat generation increases with temperature as a single or multiple S-shaped curves, whereas surface heat removal increases linearly. The shapes of these heat-generation curves and the slopes of the heat-removal lines depend on reaction kinetics, activation energies, reactant concentrations, flow rates, and the initial temperatures of reactants and coolants (70). The intersections of the heat-generation curves and heat-removal lines represent possible steady-state operations called stationary states (Fig. 15). Multiple stationary states are possible. Control is introduced to estabHsh the desired steady-state operation, produce products at targeted rates, and provide safe start-up and shutdown. Control methods can affect overall performance by their way of adjusting temperature and concentration variations and upsets, and by the closeness to which critical variables are operated near their limits. 

Fp = feed flow rate Cp = feed solute concentration pHp = feed pH Fp = concentrate flow rate Cp = concentrate solute concentration... 

Thus damage locations, although usually widespread, are dependent on many factors. Metallurgy, deposition, design, temperature, pH, water content, dissolved-ion concentration, flow, and other factors all influence attack. 

The more usual method of presenting data on the corrosiveness of various chemicals is by reference to a specific class of metal or material. Thus in the present book, the sections devoted to individual classes of materials contains lists of chemicals and in some cases details of their behaviour under various conditions of concentration, flow and temperature (see in particular the sections devoted to metals and alloys). 

Figure 4.8 Schematic of an electrospray probe with a concentric flow of nebnlizing gas. From applications literature published by Micromass UK Ltd, Manchester, UK, and reproduced with permission.

Atmospheric-pressure chemical ionization (APCI) An ionization memod in which a liquid stream is passed through a heated capillary and a concentric flow of a nebulizing gas. Ions are formed by ion-molecule reactions between me analyte and species derived from me HPLC mobile phase. 

The rabbit and l5mx problem does have stable steady states. A stable steady state is insensitive to small perturbations in the system parameters. Specifically, small changes in the initial conditions, inlet concentrations, flow rates, and rate constants lead to small changes in the observed response. It is usually possible to stabilize a reactor by using a control system. Controlhng the input rate of lynx can stabilize the rabbit population. Section 14.1.2 considers the more realistic control problem of stabilizing a nonisothermal CSTR at an unstable steady state. 

A polymer of the polyacrylamide type was injected as a 0.5% solution from an axially-placed nozzle at the bellmouth entrance. The experiments showed that the central thread provided drag reduction almost equivalent to premixed solutions of the same total polymer concentration flowing in the pipe. Overall concentrations of 1, 2, 4, and 20 ppm were used. Moreover, the effects were additive 2 ppm thread overall concentration plus 2 ppm premixed gave drag reductions equivalent to 4 ppm of either type. Reynolds numbers of up to 300,000 were investigated. In other experiments, a number of different polymer fluids were injected on the centerline of a water pipe-flow facility [857]. Two distinct flow regions were identified ... 

Regions Concentrations Flow vectors Bulk solution Tangential flow ... 

Concentration Catalyst concentration Flow rate Reaction constant... 

Concentration Flow rate Rate constant Reaction order Reaction rate Time... 

Two aqueous streams containing salt at differing concentrations flow continuously into a well-mixed tank and a mixed-product stream is removed. In this case, the densities of the streams are not assumed constant but vary as a function of concentration. All three streams can have time varying flow rates, and hence the concentration and volume of liquid in the tank will also vary with time. 

Both reactants behave reversibly. The curve is as shown in Figure 6.16(a) and is exemplified by the titration of Fe(II) with Ce(IV) when a potential of 0.1 V is applied to the cell. At the outset, no current flows because only Fe(II) is present, the only electrode reaction possible being Fe2+ —> Fe3+ + e at the anode. Upon the addition of the first increment of titrant and up to the equivalence point, the concentration of Fe(II) diminishes, whilst that of Fe(III) increases, and a current proportional to the smaller of the two concentrations flows in the cell, resulting in a maximum at the half-way stage. At the equivalence point only Fe(III) and Ce(III) are present and no current flows because neither electrode reaction Fe(III) — Fe(II) nor Ce(III) — Ce(IV) can proceed at the potential of 0.1 V. After the equivalence point, the current increases linearly with the rise in concentration of Ce(IV), that of Ce(III) being constant. 

The design of a pneumatically assisted ESI interface differs from the pure electrospray interface in that it provides a pneumatic assistance for the spray process. This is achieved by admitting a concentric flow of an inert gas such as nitrogen around the electrospray plume. [56-58] Pneumatic assistance allows for higher flow rates and for a reduced influence of the surface tension of the solvent used. [59] Pneumatically assisted ESI can accommodate flow rates of 10-200 pi min ... 

API-electrospray ionization involves three stages. First, there is the formation of charged droplets. Once the droplets are formed, solvent evaporation and droplet fission occur. Droplet fission is due to an increase in charge repulsion at the surface of the droplet as the solvent evaporates. Once the droplets become small enough (<10 nm), it is believed that charge repulsion produces ion evaporation from the surface of the droplet. Thus, ions are transferred from the solution to the gas phase. Factors affecting the production of the desired ions include analyte concentration, flow rate, matrix content, and analyte surface activity. In... 

Fig. 3.1 Relative capital costs of common methods for concentrate disposal with increasing concentrate flow rate. Adapted from Mickley (2009)...

Coagulants, which are present in filter backwash, are of low toxicity and are not considered a major environmental concern. One of the greatest effects of coagulants comes through the use of ferric salts, which are likely to cause colouration and increase the turbidity of the backwash (Lattemann and Hopner 2008). The quantity of coagulants in the concentrate can in part be regulated by the slow release of filter backwash from a buffer tank into the concentrate flow. 

Successful operation of an injection well relies on the prediction of the direction and rate of concentrate flow, the displacement of pre-existing water, and the aquifer pressure change over time can be estimated. A knowledge of the subsurface hydrodynamics is therefore required to assist in these predictions (Shammas et al. 2009). 

It is possible for a potable water source to be connected to the injection zone with no confining layer or impermeable material as a barrier. An example of this can be seen in Fig. 5.2. Injection may continue if the concentrate flows away from the connected aquifer and there is no threat of contamination. Nonetheless, the prediction and knowledge of the movement and final location of the waste front is a crucial factor. 

Five basic nebulizer designs, known to be used on ICP systems are cross flow, concentric, flow shear, ultrasonic, and FAA. The cross flow and concentric designs are most commonly supplied with commercial systems. FAA nebulizers were supplied with early multi-element systems and there are some commercial suppliers who provide ultrasonic nebulizers. 

Side processes may bring about either an increase or a decrease in measured retention volumes. Often, the presence of side processes in the SEC system is signalized by the increased dependence of polymer retention volumes on the operational parameters such as the sample concentration, flow rate, and temperature. 

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