Contaminant balance

The inlet concentration into a storage vessel is defined in constraints (6.17). The concentration within the vessel is defined in constraints (6.18). It is assumed in constraints (6.18) that the storage vessel is perfectly mixed, hence the uniform concentration throughout the vessel. The initial concentration within the storage vessel is given in constraints (6.19). Constraints (6.20) ensures that the amount of water used from the storage vessel is less than the maximum amount allowable in the receiving unit. It is important to note that the contaminant balances presented below hold for each contaminant present within the system. 

Due to the presence of contaminants in the system, contaminant balances also have to be derived around a unit. The first of these is an inlet contaminant balance, given in constraint (7.3). This constraint states that the contaminant mass entering a unit comprises of the contaminant mass present in the directly recycled/reused water and the contaminant mass present in water from various storage vessels. Important to note is that constraint (7.3) holds for every contaminant in the system. 

A contaminant balance over a unit is given in constraint (7.4). This constraints states that the mass of contaminant c leaving a unit is the sum of the mass of contaminant c that entered the unit and the mass load of contaminant c added to the water due to the operation in the unit. 

One would notice that there are a number of nonlinear terms in the above constraints, specifically in the contaminant balance constraints. The linearisation technique used to remove these nonlinearities is that proposed by Quesada and Grossman (1995), the general form of this linearization technique can be found in Appendix A. During the application of the model to the illustrative examples,... 

Due to the fact that the contaminant mass in the wastewater is assumed to be negligible at this stage, one does not have to consider contaminant balances. 

As with the mass balances over a unit, contaminant balances around a storage vessel are not required due to the contaminant mass being negligible at this stage. 

Due to the elevated contaminant mass load a contaminant balance also has to be included in the wastewater storage constraints. This is given in constraint (8.54), where the contaminant mass present in a storage vessel at a time point is the contaminant mass from the previous time point and the difference between the contaminant mass entering and exiting the vessel. Each storage vessel is assumed to be ideally mixed, hence the concentration within the vessel is uniform. 

Constraint (9.14) is a contaminant balance over a processing unit operating in inherent storage mode. It is assumed in constraint (9.14) that the unit is ideally mixed. 

Significant charge loss also occurred when a nonradioactive microdroplet was injected in a C-contaminated balance. Figure 7 presents results obtained by Davis et al. for a droplet of dioctyl phthalate in a balance that had been contaminated by prior experiments. The voltage rapidly increased as the droplet charge was neutralized, and within two minutes the charge decreased from about 165,000 elementary charges to about 10,000. 

Cinmax and Coutmax are maximum inlet and outlet concentrations. Contaminant balance at the regeneration processes... 

Mass balances over a storage vessel include a water balance and if necessary a contaminant balance. The formulation is capable of dealing with both the scenario where the contaminant mass in the washout water is negligible and not. 

To quantify the elements deposited on the catalyst surface as a function of exposure time in the flue gas duct, their relative atomic fractions x were recorded with exposure time (Fig. 4). An increase in sulfur and arsenic contents with exposure time can be observed. Both elements were first detected after 48 h. Depending on exposure time, these elements cover increasingly large areas, 10% after 96 h, 20% after 3270 h. At the same time, all samples were observed to determine whether the detected Xjj decreases with exposure time (Fig. 5). This reduction is particularly pronounced between 24 h and 48 h. After about 400 h of exposure time, the titanium fraction has decreased to about one third of its initial value. Since it does not change after this time, it is assumed that the catalyst surface contamination process is completed. From this time on, a constant balance should be achieved between abrasion and contamination. Surprisingly, this does not hold for sulfur and arsenic. It is assumed that the modified catalyst surface involved in this abrasion/contamination balance forms a further reactive component for these elements. There is other interesting evidence that the arsenic deposited originates, at least from that point on, exclusively in the gas phase, since the arsenic entrained by the flue dust would otherwise result in an increase in Xgj. 

Match the lowest concentration source with the lowest concentration sink. If contaminant balance is not complete, match the next lowest concentration source with this sink. 

Mixers for regeneration units water and contaminant balances (fory = 1, 2,...NR and... 

Mixers for waste water water and contaminant balances... 

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