| Oleg Systems Co. engineers industrial packed air | | | | Canadian Air Systems Wet-Packed Scrubbers: |
| scrubbers for air cleaning. Wet type dust | | | | HORIZONTAL COCURENT SCRUBBER. |
| collectors / packed air scrubbers are available in | | | | This wet scrubber depends on the gas velocity to |
| numerous designs utilizing a number of principles | | | | carry the liquid into the packed bed. It operates |
| and featuring wide variation in effectiveness, initial | | | | as a wetted entrainment separator with limited |
| cost, operating and maintenance expense, space, | | | | gas and liquid contact time. The gas velocity in the |
| arrangements and material of construction. Wet | | | | collector is limited by liquid retrainment to about |
| type dust collectors are liquid (usually, but not | | | | 650 fpm. |
| necessarily, water) to capture and separate | | | | VERTICAL COCURENT SCRUBBER. |
| particulate matter (dust, mist, and fumes) from a | | | | Vertical cocurent scrubber can be operated at |
| gas stream. Some scrubbers operate by spraying | | | | very high pressure drop - 1 to 3 in. of water per |
| the scrubbing liquid into the contaminated air. | | | | foot of packing depth) because there's no flooding |
| Others bubble air through the scrubbing liquid. | | | | limit for the superficial velocity. |
| Wet Packed Scrubbers are used to remove | | | | CROSS-FLOW SCRUBBER. |
| gaseous and particulate contaminants from gas | | | | This scrubber uses downward-flowing liquid and a |
| streams. Scrubbing is accomplished by | | | | horizontally moving air stream. The effectiveness |
| impingement of particulates and/or by absorption | | | | of absorption processes in cross-flow scrubbers |
| of soluble gas or vapor molecules on the | | | | lies between those for cocurrent and |
| liquid-wetted surface of the packing. Gas or vapor | | | | countercourent flow scrubbers. |
| removal is more complex than particulate capture. | | | | COUNTERCURRENT SCRUBBER. |
| The contaminant becomes a solute and has a | | | | Countercurrent scrubber uses a |
| vapor pressure above that of scrubbing liquid. This | | | | downward-flowing liquid and an upward-flowing |
| vapor pressure typically increases with increasing | | | | gas. The gas-handling capacity of this wet |
| concentration of the solute in the liquid and with | | | | scrubber is limited by pressure drop or by liquid |
| increasing liquid temperature. Scrubbing of the | | | | entrainment. The contact time can be controlled |
| contaminant continues as long as partial pressure | | | | by the depth of the packing used. This type of |
| of contaminant in the gas is above its vapor | | | | wet scrubber gives the best removal of gaseous |
| pressure with respect to the liquid. The rate of | | | | contaminants while keeping liquid consumption to a |
| contaminant removal is a function of the | | | | minimum. The effectiveness of absorption |
| difference between the partial pressure and vapor | | | | processes is maximized because the exiting gas is |
| pressure, as well as the rate of diffusion of the | | | | in contact with fresh scrubbing liquid. |
| contaminant. | | | | Wet type dust collectors are liquid (usually, but not |
| Scrubber packings are designed to present a large | | | | necessarily, water) to capture and separate |
| surface area that will wet evenly with liquid. High | | | | particulate matter (dust, mist, and fumes) from a |
| efficiency packings promote turbulent mixing of | | | | gas stream. Some scrubbers operate by spraying |
| the gas and liquid. Packings are available in ceramic, | | | | the scrubbing liquid into the contaminated air. |
| metal, and thermoplastic materials. | | | | Others bubble air through the scrubbing liquid. In |
| There are four different arrangements of | | | | addition, many gybrid wet scrubbing designs exist. |