Scrubbing operation design

T. F. O Brien, Emergency Vent Scrubbing Systems—Design Operation Hazard Analysis, Seventh Annual Electrode Corporation Chlorlne/Chlorate Seminar, Cleveland, OH (1991). 

Use chemical interaction matrices to identify potential incompatibilities between combinations of materials (not just binary reactions) and interactions with cleaning solvents, heat transfer fluids and other utilities, equipment lubricants, scrubbing media, materials of construction, etc. Implement management of change procedures for changes in design, operation, equipment and chemistry. 

Chlorine is to be removed from a vent stream by scrubbing with a 5 per cent w/w aqueous solution of sodium hydroxide. The vent stream is essential nitrogen, with a maximum concentration of 5.5 per cent w/w chlorine. The concentration of chlorine leaving the scrubber must be less than 50 ppm by weight. The maximum flow-rate of the vent stream to the scrubber will be 4500 kg/h. Design a suitable packed column for this duty. The column will operate at 1.1 bar and ambient temperature. If necessary, the aqueous stream may be recirculated to maintain a suitable wetting rate. 

Is the ventilation system appropriately designed for indoor operation (and scrubbing, if required) by local codes in effect at the time of construction or major modification ... 

The fan which must be designed in such a way that it can cope with the necessary aii volume and also the pressure difference in the scrubber, is located in the lid of the scrubber. The water distributor which must be able to operate without restriction from skin, hair and such particles in the scrubbing liquid, is located at the lower edge of the lid. 

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