Slurry liquid phase sulfite concentration

Gladkii(16) at the State Scientific Research Institute of Industrial and Sanitary Gas Cleaning at Moscow did work on the three-phase calcium sulfite slurry oxidation system, finding that the liquid phase oxidation (pH 3.6-6) is first order with respect to the sulfite species. He pointed out, on the basis of pH versus time data from his semi-batch reaction, that the slurry oxidation had different periods in which either reaction kinetics or solid-liquid mass transfer controlled the oxidation rate. He also presented an omnibus empirical correlation between pH, temperature, and the liquid phase saturation concentration of calcium sulfite solution for predicting the slurry oxidation rate. The catalytic effect of manganese... 

The liquid phase concentration of sulfite in the slurry is governed by two competing mechanisms. Sulfite in the liquid is lost due to the oxidation reaction, but is replenished by the dissolution of the solid calcium sulfite. The sulfite concentration is represented by a differential equation of the form ... 

The total concentration of sulfite in the slurry at any time, C, Is the sum of liquid phase concentration and the remaining solid phase concentration ... 

Oxidation in a three phase system is a very complicated process. The rate of oxidation can depend on mass transfer of oxygen from the gas to the liquid, on the rate of solid dissolution, and on chemical kinetics. These three processes are closely interrelated and the relative importance of any one depends on the conditions in the scrubber or hold tank. The individual steps of these processes include the gas to liquid transport of oxygen, the solid to liquid mass transfer of sulfite, the precipitation of sulfates, and the chemical reaction. The rates of these steps depend on the concentrations of reacting and nonreacting species in the slurry, on pH, on slurry density, and on the design of the reactor. 

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