Turbulent contacting absorber

The term three-phase fluidization requires some explanation, as it can be used to describe a variety of rather different operations. The three phases are gas, liquid and particulate solids, although other variations such as two immiscible liquids and particulate solids may exist in special applications. As in the case of a fixed-bed operation, both co-current and counter- current gas-liquid flow are permissible and, for each of these, both bubble flow, in which the liquid is the continuous phase and the gas dispersed, and trickle flow, in which the gas forms a continuous phase and the liquid is more or less dispersed, takes place. A well established device for countercurrent trickle flow, in which low-density solid spheres are fluidized by an upward current of gas and irrigated by a downward flow of liquid, is variously known as the turbulent bed, mobile bed and fluidized packing contactor, or the turbulent contact absorber when it is specifically used for gas absorption and/or dust removal. Still another variation is a three-phase spouted bed contactor. 

Figure 7. Predicted (Equation 10) vs. measured SOz removal for the Shawnee (9) 10-MW turbulent contact absorber...

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. 

Venturi scrubber, turbulent contact absorber, marble bed absorber, horizontal spray chamber, cocurrent rotator. Based on data qf Frank, 1977... 

The 1984 Chang report is quite comprehensive and presents the results of a series of tests conducted in a 0.1 MW, FGD pilot plant which employs a three-stage turbulent contact absorber (TCA). lii addition to experimental data, the report includes a discussion of the chemical reactions and mass transfer phenomena involved. The theory shows, for example, that increasing the Cl ion concentration from 200 to 100,(XX) ppm (in the form of CaCl2) reduces the total alkalinity (HCOs", CaHC03, SOs , and CaS03) by over 40%. The decreased alkalinity would be expected to decrease the rate of reaction of dissolved SO2, causing a decrease in the liquid phase mass transfer rate and, therefore, a reduction in SO2 removal efficiency. 

The primary goal consists in the determination of the dependence of r/ on the parameters describing the gas and the absorbent, and on geometrical dimensions of the contact chamber. Direct the x-axis along the contact chamber axis, so that X = 0 corresponds to the entrance cross-section. Assume that the absorbent is atomized in the gas flow and forms drops of identical radius equal to the stable radius of drops in a turbulent flow ... 

Absorption. When the two contacting phases are a gas and a liquid, the unit operation is called absorption. A solute A or several solutes are absorbed from the gas phase into a liquid phase in absorption. This process involves molecular and turbulent diffusion or mass transfer of solute A through a stagnant nondiffusing gas B into a stagnant liquid C. An example is absorption of ammonia A from air B by the liquid water C. Usually, the exit ammonia-water solution is distilled to recover relatively pure ammonia. 

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