Method and apparatus for effecting gas-liquid contact

A method of the removal of a gaseous component from a gas stream containing the same with a chemical conversion agent in a liquid medium to form an insoluble phase which comprises:

• feeding said gas stream to an enclosed gas-liquid contact zone in which is located said liquid medium,
• rotating an impeller comprising a plurality of blades about a generally vertical axis at a submerged location in said liquid medium so as to induce flow of said gas stream along a generally vertical flow path from external to said gas-liquid contact zone to said submerged location,
• surrounding said impeller with a shroud through which are formed a plurality of openings while said impeller is rotated at a speed corresponding to a blade tip velocity of at least about 350 in/sec so as to draw liquid medium into the interior of the shroud and to generate sufficient shear forces between said impeller blades and said plurality of openings in said shroud to distribute said gas stream as fine gas bubbles of diameter no more than about 1/4 inch in the liquid medium to the interior of said shroud, and to effect intimate contact of said component and liquid medium at said submerged location so as to form a gas-liquid mixture of fine gas bubbles in said liquid medium contained within said shroud and to effect removal of the component from the gas stream into the liquid medium,
• flowing said gas-liquid mixture of fine gas bubbles and liquid medium from the interior of the shroud through and in contact with the openings therein into the body of the liquid medium external to the shroud at a gas velocity index at approximately atmospheric pressure of at least about 18 per second per opening in said shroud, so as to effect further shearing of said fine gas bubbles and further intimate contact of said gas stream and said liquid medium, whereby any removal of component from the gas stream not effected in the interior of the shroud is completed in the region of the liquid medium adjacent to the exterior of the shroud,
• said gas velocity index (GVI) being the ratio of the linear velocity (V) of the gaseous phase through each opening to the equivalent diameter (d) of the opening, as determined by the expression:
• ##EQU3## where d is determined for each opening by the expression:
• ##EQU4## where A is the area of the opening and P is the length of the perimeter of the opening, and
• venting a component-depleted gas stream from a gas atmosphere above the liquid level in said gas-liquid contact zone to exterior of said enclosed gas-liquid contact zone.