Features

• Air flow rate from 50 to 30000 CFM
• Material of construction: PP, PP+FRP, MS, SS 304, SS 316
• Scrubbing efficiency up to 99 % Lower shell serves as integral sump for recycle of liquid
• Spray nozzles accessible from top of unit
• Entrainment separators prevent liquid carryover
• Special multi-bed packing designs accommodate different scrubbing solutions for removal of multiple contaminants

Application

• Storage tank vent scrubbing
• Exhaust HCl gas scrubbing
• Reactor HCl vent scrubbing
• Process vent scrubbing
• Laboratory HCl scrubbing

Mechanism

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.

HCl Exposure Limits

• NIOSH REL : 5 ppm (7 mg/m³)
• OSHA PEL :  5 ppm (7 mg/m³)
• IDLH (Immediately dangerous to life or health) : 50 ppm

Working principle

• 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.
  

Chemistry of HCl with NaOH

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

Drizgas Tech provides the complete scope of services for fume ventilation and scrubbing systems including the following:

• Engineering & Design
• Fume Scrubber Fabrication
• Custom Hoods & Enclosures
• Complete Ventilation Systems
• Makeup Air Systems
• System Installation & Start-up
• System Upgrades & Repairs
• Airflow Measurements & Balancing
• Preventative Maintenance Programs

 

Several key points are controlled and alarms are programmed in the PLC to control and indicate all part of the equipment are meeting the criteria such as the following:

• Circulation Pumps Start/Stop Control
• Motor Overload
• Circulation Flow Rate
• Chemical Feed Pump
• pH of Reservoir
• pH Set Points
• Level in Scrubber Reservoir
• Blow Down
• Chemical Feed Drum Level
• Makeup Air System Flow
• Push Air System Flow
• Static Pressure of Scrubber
• Water Makeup
• Makeup Air and Scrubber Blower

Applications

• Steel and Mining industry,
• Electric power plants,
• Oil and gas extraction operations,
• Oil refineries,
• Pulp and paper mills,
• Sewage treatment plants,
• Large poultry farms ,
• Portland cement kilns,
• Municipal waste landfills,
• Coke ovens,
• Sulfur products and hydrogen sulfide production,
• Asphalt production and storage etc.