Gas Dehydration in Counter-Current Absorbers with High-Speed Separation-Contact Elements

Gas Dehydration in Counter-Current Absorbers with High-Speed Separation-Contact Elements 

Recently, column absorbers for gas dehydration have begun to adopt high-speed direct-flow centrifugal separation-contact elements with tangential input of gas and recirculation of the absorbent (see Fig. 2.17). These elements are installed on 

Since the absorbent flows continuously from plate to plate and is also repeatedly diluted by the absorbent coming out of the elements, the state of the absorbent layered on the plates can be characterized by residence times inside the element tg = Lgfug, and at the plate f = V/Qa, where V is the absorbent volume at the plate, Lg is the height of the element, Q is the absorbent flow rate, and Ug is the average vertical drift velocity of the gas inside the element (i.e. velocity along the symmetry axis of the element). A comparison of these two times for the characteristic parameter values shows that tg t). This means as it dwells at the plate, the absorbent has enough time to make numerous contacts with the gas inside the elements installed on this plate. 

The key parameter describing the absorbent state is the recirculation number, defined as the ratio of the absorbent flow rate through the contact elements to the general absorbent flow rate in the absorber. 

In practical terms, the parameter n determines how many times a volume V of the absorbent will pass through elements located at one plate during its residence time tt at the plate. The primary goal is to find out how the concentrations of glycol in the absorbent solution and of moisture in the gas at the exit from the element depend on the number n of recirculations. 

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