Bubble injection Contact time

From Equation 8, it can be derived that the vaporization efficiency increases with an extension of the total surface area and with the time of contact between steam bubble and oil. In practice, the vaporization efficiency can be influenced by the depth of the oil layer and the steam injection geometry. The shallower the oil layer, the higher the risk that the steam leaves the oil surface without being saturated. At the other extreme, for deep oil layers, the contact time is longer but then problems can occur with the agitation, leading to an insufficient renewal of the upper oil layer and a nonuniformly treated oil mass. 

A gas stream is injected at the bottom of a vessel filled with liquid and bubbles through the liquid phase [15, 16]. At the same time, the liquid evaporates into the gas bubbles until the exact equilibrium saturated vapor pressure, Py, (with sufficient duration of contact time) is reached. 

Stacked unit configuration with the regenerator above the reactor Ultra low contact time achieved via feed injection perpendicular to a shaped falling curtain of catalyst Reaction products pass to external cyclones while the spent catalyst falls into a stripper and air lifted into a bubbling bed regenerator ... 

In Fig. 21.20c, which corresponds to a higher ALR of 0.1 (liquid volume flow rate of 30 L/h), large deformed bubbles are visible in the injection area. As the gas bubbles detach from the injection holes, they again come into contact with those emerging from downstream injection holes. This leads to bubble coalescence and to the formation of an annular flow pattern. This time, the annular flow remains stable, however. 

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