Hydrogen Chloride

Hydrogen Chloride / Hydrochloric Acid

Hydrogen Chloride (HCl) is a colorless gas with an irritating, pungent odor.  Hydrogen Chloride gas evolves from solutions of Hydrochloric Acid. HCL is soluble in water and has a relatively high vapor pressure.   Hydrochloric Acid is one of the most commonly used acids in a variety of industrial processes.

Applications

Hydrochloric Acid gas emissions are present across a variety of industries including metal processing and finishing, agricultural, fertilizer, semiconductor, chemical production, mining as well as food and beverage processing.   HCl is widely used in steel and alloy industries for pickling and descaling various metals.  HCL is commonly a cleaning step in prior to electroplating and metal finishing.  

Health and Environmental Effects

Hydrogen Chloride exposure is irritating to the skin, eyes, nose, throat, and lungs. It is highly hazardous in great concentrations.  Hydrochloric Acid is very corrosive to mild and stainless steels.  

Regulatory Considerations

Hydrochloric Acid is considered a hazardous air pollutant (HAP) by the US EPA.  The US EPA regulates Hydrochloric Acid emissions from HCL production facilities through its National Emission Standards for Hazardous Air Pollutants. Many state and local authorities require HCL storage tank emissions to be controlled by a vent scrubber during HCL tanker loading and filling operations

Control Technologies

HEIL Series 730 Counter-Current packed tower scrubbers are the most common technology for high efficiency scrubbing of Hydrogen Chloride.  Heil Series 740 tray scrubbers are also specified in certain applications where the customer desires to recover HCL emissions captured in the scrubber for reuse.  Sodium Hydroxide is often used to neutralize the pH of the scrubbing solution.  

Heil HCL Scrubbers can achieve removal efficiencies greater than 99.9%.  In certain applications, a hydrochloric acid fog is created within the air stream.  Heil composite mesh entrainment separators can effectively remove HCL fog emissions down to 1 micron.