HCl fume scrubber
HCl fume scrubber is mostly used an acid storage tank system. A properly designed Hcl fume scrubber will eliminate the release of irritating and corrosive vapors of hydrochloric acid into the workplace and atmosphere.
The scrubber design will depend upon a number of factors including: method of offloading from tank car or tank truck (air pressure or pump), the ability to reuse dilute acid solutions which may be generated from the scrubbing operation, and permitting requirements needed in order to discharge or dispose of acidic solutions or other solutions generated as a result of the scrubbing operation.
NIOSH REL : 5 ppm (7 mg/m3)
OSHA PEL : 5 ppm (7 mg/m3)
IDLH (Immediately dangerous to life or health) : 50 ppm
The recirculating scrubber and the packed column scrubber are the two scrubbing systems used most commonly. The Recirculating Scrubber consists of a pump, lines, eductor, scrubber tank, and sparger.
In this system, the fume eductor draws acid vapors from the storage tank. The acid vapors are then absorbed by water being recirculated through the eductor.
The solution in the scrubber tank gradually builds strength up to a maximum of 15% HCl. At this point, the weak acid solution should be removed for use or sent to an appropriate hazardous waste treatment site.
The scrubber tank is then recharged with fresh water. No acid is lost and the fumes from the hydrochloric acid are contained by the system.
In the Packed Column Scrubber water is fed into the top of a packed column and acid vapors from the storage tank are fed into the bottom.
The acid vapors are removed from the air by scrubbing them with the countercurrent flow of water. The air then vents out of the top of the scrubber and the weak acid flows into a suitable chemical waste handling system.
Hydrochloric acid reacts with sodium hydroxide to form sodium chloride (the salt) and water. Sodium chloride is made up of Na+ cations from the base (NaOH) and Cl- anions from the acid (HCl).
HCl + NaOH → H2O + NaCl