Mass balance concentrations ratios

Capture efficiency can also be measured by first estimating workspace emission rates and local exhaust emissions. The local exhaust emission rate equals the duct concentration (mass/volume) multiplied by the duct flow rate (volume/time). The workspace emission rates can be calculated using appropriate mass balance models and measured ventilation rates and workspace concentrations. Capture efficiency is the ratio of duct emission rate to total emission rate (duct plus workspace). ... 

It is often experimentally convenient to use an analytical method that provides an instrumental signal that is proportional to concentration, rather than providing an absolute concentration, and such methods readily yield the ratio clc°. Solution absorbance, fluorescence intensity, and conductance are examples of this type of instrument response. The requirements are that the reactants and products both give a signal that is directly proportional to their concentrations and that there be an experimentally usable change in the observed property as the reactants are transformed into the products. We take absorption spectroscopy as an example, so that Beer s law is the functional relationship between absorbance and concentration. Let A be the reactant and Z the product. We then require that Ea ez, where e signifies a molar absorptivity. As initial conditions (t = 0) we set Ca = ca and cz = 0. The mass balance relationship Eq. (2-47) relates Ca and cz, where c is the product concentration at infinity time, that is, when the reaction is essentially complete. 

N, and solute passage Si needed to produce desired retentate product with impurity concentrations Cj and retentate product yield Mj/Mjo. Permeate product characteristics for batch operation can be determined by mass balances using a permeate volume of Vp = Vo(l 1/X + N/X), a mass of solute i in the permeate as Mj perme e = Mjo(l — and the permeate concentration as the ratio of the... 

Constraints (5.1) states that the inlet stream into any operation j is made up of recycle/reuse stream, fresh water stream and a stream from reusable water storage. On the other hand, the outlet stream from operation j can be removed as effluent, reused in other processes, recycled to the same operation and/or sent to reusable water storage as shown in constraints (5.2). Constraints (5.3) is the mass balance around unit j. It states that the contaminant mass-load difference between outlet and inlet streams for the same unit j is the contaminant mass-load picked up in unit j. The inlet concentration into operation j is the ratio of the contaminant amount in the inlet stream and the quantity of the inlet stream as stated in constraints (5.4). The amount of contaminant in the inlet stream to operation j consists of the contaminant in the recycle/reuse stream and the contaminant in the reusable water storage stream. Constraints (5.5) states that the outlet concentration from any unit j is fixed at a maximum predefined concentration corresponding to the same unit. It should be noted that streams are expressed in quantities instead of flowrates, which is indicative of any batch operation. The total quantity of water used at any point in time must be within bounds of the equipment unit involved as stated in constraints (5.6). Following are the storage-specific constraints. 

The scaling tendency of the lime or limestone processes for flue gas desulfurization is highly dependent upon the supersaturation ratios of calcium sulfate and calcium sulfite, particularly calcium sulfate. The supersaturation ratios cannot be measured directly. They are determined by measuring experimentally the molalities of dissolved sulfur dioxide, sulfate, carbon dioxide, chloride, sodium and potassium, calcium, magnesium, and pH. Then by calculation, the appropriate activities are determined, and the supersaturation ratio is determined. Using the method outlined in Section IV, the concentrations of all ions and ion-pairs can be readily determined. The search variables are the molalities of bisulfite, bicarbonate, calcium, magnesium, and sulfate ions. The objective function is defined from the mass balance expressions for dissolved sulfur dioxide, sulfate, carbon dioxide, calcium, and magnesium. This equation is... 

Equation (21) is an excellent approximation to Equation (20) for moderate to high kj/kj ratios ( 10 and higher) for processes that occur by first-order kinetics. It is important to note, however, that a specific rate law does not appear anywhere in Equations (20) and (21), and they are equally valid for any reaction process where Xpejm) is small. Equation (21) illustrates that oxidation of Fe(II)a, to Fe(III)a, produces a markedly different isotopic mass balance than that associated with DIR. In cases where the product of DIR is Fe(II)aq, the concentration of this component is continually increasing, changing the relative mass balance among the exchangeable pools of Fe over time. 

Here, / is the membrane thickness in the swollen state at constant pH and temperature, and is the ratio of the solute concentration in the membrane to the solute concentration the solution at equilibrium, which can be calculated from mass balance. 

Impacts on mass balance but should not affect concentration ratio if system is at equilibrium. 

The band profile obtained as a numerical solution of Equation 10.10 gives the concentration distribution as a function of the reduced time at the column end, i.e., at location x= 1, regardless of the column length. The band profile depends only on the column efficiency, the boundary conditions, the phase ratio, and the sample size (which is part of the boundary conditions). The mobile phase velocity has been eliminated from the mass balance equation and the apparent axial dispersion coefficient has been replaced by the plate number. 

Let us formulate the dynamic mass balance equation of the chemical in the SMSL. Fig.23.5 summarizes all processes. At this point we have to select the variable which shall characterize the SMSL. (Remember for the open water box we have chosen the total concentration Ctop.) Due to the large solid-to-water ratio of sediments rss, chemicals with moderate to large distribution coefficients (Kd > 0.1 m3kg ) are predominantly sorbed to the solid phase. Therefore, C offers itself as the natural choice for the second state variable. 

Mass balance was obtained by the ratio of the total C or Cl of reaction products to that of the substance decreased.(Inital concentration of Ag+ was 50 mmol dm-3.)... 

Figure 8 also shows the mass balance model predictions for two runs. The mass balance model does a reasonable job of predicting the product concentration for the low cycle time. Here the predicted values are lower than the experimental values, differing by a factor of approximately two. However, for a cycle time of 12 minutes, the prediction falls short of the experimentally determined value. The critical value of y 3 1.0 was used in the model calculations. If 1.3 were used for the purge to feed ratio as suggested by Skarstrom (4), or a value closer to 3 as found in these experiments, the agreement would be slightly better for both runs. 

According to equation (2.3), the Henry s law constant can be estimated by measuring the concentration of X in the gaseous phase and in the liquid phase at equilibrium. In practice, however, the concentration is more often measured in one phase while concentration in the second phase is determined by mass balance. For dilute neutral compounds, the Henry s law constant can be estimated from the ratio of vapor pressure, Pvp, and solubility, S, taking the molecular weight into consideration by expressing the molar concentration ... 

No magnesium sulfate was added to the system for run MG-3. The objective of this run was to evaluate the system performance with decreasing Mg2+ concentration. The mass balance indicated that the total Mg2 concentration should drift down to below 500 ppm. During the run, the total Mg2+ concentration decreased from 1000 ppm to about 625 ppm toward its end. A leak was discovered at the scrubber bleed/quench recirculation pump inlet which introduced air into the process stream and therefore caused high oxidation. The high oxidation, as confirmed by solids analysis results in Table 3, was reflected by increases of the sulfate-to-sulfite ratio to above 2.5. After the air leak problem was corrected, the sulfate-to-sulfite ratio decreased, but the test average was 2.4. 

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