摘要 |
An apparatus and method of contacting a liquid with different gases sequentially in separate mass transfer zones within a single vessel, the mass transfer zones operatively in fluid communication with each other, including intimately contacting the liquid with a process gas in co-current flow in a downstream mass transfer zone to effect mass transfer between the liquid and the process gas, and introducing the liquid into an upstream mass transfer zone with a second gas, different from the process gas, thereby effecting mass transfer between the liquid and the second gas. The rate of flow of the liquid from the upstream mass transfer zone to downstream mass transfer zone is controlled by the controlled addition of a third gas into one or more downcomers separating each mass transfer zone such that the specific density of the liquid in the downcomers provides a driving force that controls flow.
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