| 摘要 |
Method and apparatus are disclosed for cooling a process gas stream having a temperature in the range from about 400 DEG F. and 3000 DEG F. and absorbing gaseous contaminants therefrom wherein contact is effected between said process gas stream and respective quench and absorbent liquids in order to provide said cooling and absorbing functions. The flow rates of the process gas stream, quench liquid, and/or absorbent liquid are subject to substantial variations due to operating conditions related to the process gas source or to the provision for contaminant recovery, requiring absorbent liquid of a desired concentration. In practice, the process gas stream may be that discharged from a waste product incinerator containing not only products of combustion but also the aforesaid gaseous contaminants. In accordance with the invention, the process gas stream is passed initially through a first treatment column in contact with a quench liquid in order to cool the gas stream, which first treatment column is of the packed, differential type which exhibits an adequate cooling efficiency over the aforesaid substantial variations in flow rate of the process gas stream and/or quench liquid. The cooled process gas stream is then passed through a second treatment column in contact with an absorbent liquid to absorb a portion of the gaseous contaminants therefrom, which second treatment column is of the equilibrium-stage type exhibiting an adequate absorption efficiency over the variations in flow rate of the process gas stream and/or absorbent liquid. The use of a "hybrid" tower, containing columns of both the packed, differential and equilibrium-stage type permits operation over much wider variations in flow rate of the process gas stream, quench liquid, and/or absorbent liquid than prior art arrangements.
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