Mixing option

Calculate the volume-corrected titration curve for the titration of 0.01 N HCl with 0.01 N NaOH between pH 2 and 12 using a geochemical computer code and compare the result to the corresponding curve in Fig. 5.5. This problem can be solved using the mixing option in SOLMINEQ.88 (Kharaka et al. 1988). The titration is simulated by mixing different fractions of solution 1 (pH = 12.0, Na" = 0.01 mol/kg) with solution 2 (pH = 2.0, Cr = 0.01 mol/kg). In the output Cg = Na". Computed results are given here. 

The mixing option in SOLMINEQ.88 is particularly useful in modeling deep well disposal of industrial waters. This option allows two different aqueous fluids to be mixed in varying proportions. At a constant or varying temperature, the variables typically monitored in the mixed fluids, are the saturation indices of the various minerals in order to determine if there will be problems with precipitation of various phases in intermediate mixtures. A detailed example of the use of this option is reported in Gunter et al. (1986), who modeled the effects of waste water disposal from enhanced oil recovery operations (EOR) in two different disposal formations. In cases where mineral precipitation is predicted, the code can be used to indicate a remedial action in the form of chemical additives, or by mixing with water of different composition (Fig. 2). 

Figure 2.56 shows the difference in performance between the two systems. The pre-mixing option provides a number of benefits regardless of the gas used. 

A number of recording options can be controlled from within ACID. These options are distinct from the gain/mixing options of your sound card, previously discussed. In fact, you cannot control the gain of the recording in ACID at all. Here is what you can control ... 

The literature is small on rotor-stator devices, as discussed in Chapter 8. [They are also discussed in Chapter 12, since this is the process result (liquid-liquid and solid-liquid) that these devices are most used for.] It should be mentioned that because of their very high speed they can produce turbulent motion in some rather high viscosity fluids. Also see Cohen (1998), Dietsche (1998), and Myers et al. (1999) for general information about the industrial application of rotor-stator mixers versus other mixing options. 

While a superstructure based on the structure in Fig. 16.26 allows for many structural options, it is not comprehensive. Wood, Wilcox, and Grossmanr showed how direct contact heat transfer by mixing at unequal temperatures can be used to decrease the number of units in a heat exchanger network. Floudas, Ciric, and Grossman showed how such features can be included in a heat exchanger network superstructure. Figure 16.27 shows the structure from Fig. 16.26 with possibilities for direct contact heat transfer included. In the... 

In many instanees, it is important tiiat some fonn of ehemieal seleetivity be applied in magnetie resonanee imaging so as to distinguish nuelei m one or more speeifie moleeular enviromnent(s). There are many ways of doing this and we diseuss here just three. The first option is to ensure that one of the exeitation RF pulses is a narrow bandwidth, frequeney seleetive pulse applied in the absenee of any gradient [22]. Sueh a pulse ean be made speeifie to one partieular value of the ehemieal shift and thereby aflfeets only nuelei with that ehemieal shift. In praetiee this ean be a reasonable method for the speeifie seleetion of fat or oil or water in a mixed hydoearbon/water system. 

Commercially important arenesulfonyl isocyanates are not directly accessible from the corresponding sulfonamides via phosgenation due to lack of reactivity or by-product formation at elevated temperatures. A convenient method for their preparation consists of the reaction of alkyl isocyanates with sulfonamides to produce mixed ureas which, upon phosgenation, yield a mixture of alkyl and arenesulfonyl isocyanates. The desired product can be obtained by simple distillation (16). Optionally, the oxalyl chloride route has been employed for the synthesis of arenesulfonyl isocyanate (87). 

In one possible sequence the MSA composition is chosen as water-saturated methylene chloride expected to be regenerated by decantation. The boundary-crossing strategic operation is to mix the feed with the MSA. The resulting two-phase mixture is opportunistically fractionated to produce the 2-propanol product as bottoms, and a mixture of water—methylene chloride as distillate. This distillate is opportunistically decanted to recover water-saturated methylene chloride MSA for recycle. The aqueous decanter phase is the water product, which optionally may be further purified by... 

The chemical-grade ore, containing about 30% chromium, is dried, cmshed, and ground in ball mills until at least 90% of its particles are less than 75 ]lni. It is then mixed with an excess of soda ash and, optionally, with lime and leached residue from a previous roasting operation. In American and European practice, a variety of kiln mixes have been used. Some older mixes contain up to 57 parts of lime per 100 parts of ore. However, in the 1990s manufacturers use no more than 10 parts of lime per 100 parts of the ore, and some use no lime at all (77). The roasting may be performed in one, two, or three stages, and there maybe as much as three parts of leached residue per part of ore. These adaptations are responses to the variations in kiln roast and the capabihties of the furnaces used. 

Note that for stable conditions and/or mixing heights greater than or equal to 10,000 m, unlimited mixing is assumed and the summation term is assumed to be zero, as noted by expressions presented earlier in this chapter. Equation (9) is used to model the plume impacts from point sources, flare releases, and volume releases in SCREEN. The SCREEN volume source option uses a virtual point source approach. The model uses a numerical integration algorithm for modeling impacts from area sources. 

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