Sulfite concentration, dissolved

Addition of magnesia to the scrubbing liquor increases the concentration of two dissolved sulfite species, SO3 and MgS0 , with CaS0 remaining constant. This increase in dissolved sulfite concentration makes the SOp absorption rate more dependent on the very fast liquid phase reactions of the basic sulfite species with the strong dibasic acid SOp(aq) ... 

Dissolved sulfite concentrations predicted from Equation 2 agree with the computerized chemical model to within a relative... 

Figure 4. Dissolved sulfite concentration as a function of magnesium concentration and chloride-to-magnesium ratio for liquors saturated with calcium sulfite and gypsum at pH 5.5 and 50°C...

Figure 8 shows the effects of dissolved sulfite concentration and slurry flow rate on SO2 removal as predicted by Equation 10 for the TCA with 15 inches of spheres and a scrubber... 

Figure 8. S01 removal as a function of dissolved sulfite concentration and slurry...

In the absence of chloride, these sulfite concentrations of 1.2, 10, and 16 m-mole/1 are achieved for dissolved magnesium concentrations of zero, 250, and 450 m-mole/1, respectively (see Figure 4). 

Dissolved sulfite concentration is a convenient basis for comparing 1imestone/magnesia scrubbing to other types of flue gas wet scrubbing systems. 

Data for magnesia-enhanced limestone scrubbing of SO2 by a Turbulent Contact Absorber were obtained from the 10-MW equivalent EPA Alkali Scrubbing Test Facility. These data and the chemical model have been used to predict the enhancement effect of magnesia-induced dissolved sulfite concentration on S02 removal. 

Sulfite standards Dissolve 1 g Na2S03 in 1 L distilled water. Standardize this solution by titration using 0.0125 N potassium iodide-iodate titrant. (See the preceding section, Tritrimetric Method in this chapter for detailed procedure.) Determine the exact concentration of this stock solution. 

An exception is metol, which is only soluble with difficulty when mixed in solutions containing a high concentration of sulfite. Therefore, when mixing developers that contain metol you should dissolve the metol before the sulfite. This has a minimal effect on the keeping properties of the developer as metol is not easily oxidized. Even so, many workers prefer to dissolve a pinch of sulfite before dissolving the metol, to ensure against oxidation. The small amount of sulfite can either be taken out of the measured amount or ignored as it is usually insufficient to upset the balance of the finished developer. 

Pjeat Exchanglil corrosion of all parts on the water side Cause the sulfite concentration was less than that recommended by the manufacturer. This have resulted in the presence of a non-negligible amount of dissolved Oj in water that has given rise to the widespread pitting. Repair phemical] ashinj ... 

Water Treatment. Sodium sulfite is an agent in the reduction of chlorine or oxygen in water. Dissolved oxygen in boiler water tends to enhance pitting and other types of corrosion. In boilers operated at below 4.82 MPa (700 psi), a residual concentration of 30 ppm of sodium sulfite is generally effective. Catalytic amounts of cobalt are often added to accelerate the reaction of oxygen with sulfite (321,322) (see Water, industrial water treatment). 

Neither the reaction to the intermediate maleic acid monoester nor the subsequent sulfation to the sulfosuccinic acid monoester sodium salt is fully complete (Scheme 2). Around 80% of the solid material is estimated to be true sulfosuccinate. Whether the unreacted material or possible side products are beneficial to the finished product has not yet been evaluated. Due to the necessity of dissolving the sodium sulfite (or bisulfite) in water, the product obtained is not normally more highly concentrated than 40% active matter. The consistency of the material varies from clear, low viscous liquids to pastes. Some substance can be spray-dried to obtain concentrated powders. 

A flowsheet for the Wellman-Lord process is shown in Figure 25.26. Again the gas stream with S02 enters a scrubber into which is sprayed a sodium sulfite solution. This then goes to an evaporator/crystallizer to crystallize out the resulting sodium bisulfite, which converts the sodium bisulfite back to sodium sulfate, releasing the S02. The crystals are dissolved in water and recycled to the scrubber. The effect of the Wellman-Lord process is to produce a concentrated S02 stream from a dilute S02 stream. The resulting concentrated S02 still needs to be treated. 

Quench the oxidation by the addition to the peptide solution of at least a 4-fold molar excess of N-acetylmethionine or sodium sulfite over the concentration of periodate in the reaction mixture. Pre-dissolve the quencher in buffer at a higher concentration prior to adding an aliquot of it to the reaction solution. React for 10 minutes. 

---