Pollution Control Systems for Metal Processing and Finishing Industries

Metal Processing and Finishing

Multi Stage Nox Scrubber

The metal processing and finishing industry has traditionally been HEIL's largest market through many decades of our company's existence.  Dating back to 1929, Heil originally began making linings and coatings for this industry.   In the 1950s and 60s, HEIL built the first FRP Fans and Air Wash Spray Towers for this industry.

In more recent decades, HEIL worked closely with large OEM Steel Pickling Facilities, designing our Heil Model 740 sieve tray scrubbers for high efficiency removal of HCL emissions in compliance with EPA Regulations, while also providing customers the ability to concentrate and reclaim the acids absorbed in our tray scrubbers for reuse.  Many HEIL FRP Fan and Scrubber systems have been continuously operating at steel pickling facilities across the united states for more than 50 years.  


To remove rust and debris from steel, it is pickled typically using HCl hydrochloric acid at various concentration and temperatures.  In order to capture the gaseous HCl present, a Heil fume exhaust scrubber system is recommended. These units are typically operated using water only to allow for reuse back in the pickling process.   An optional chemical addition system to produce a stable salt product in solution is also available.  The fume exhaust scrubber system can include the hoods/covers, ductwork, either a Heil Model 730 Vertical Countercurrent Packed Bed Scrubber or a Heil Model 740 Sieve Tray Scrubber, recirculation system, tank(s), fan(s), stack, instrumentation and controls.

Stainless steel and alloy pickling

Absorber Installation

Stainless steel and alloy pickling also removes imperfections and surface debris.  HNO3 (Nitric acid) is typically used for pickling stainless steel at various concentrations and elevated temperature.  It is during this chemical process, that NOx gases, typically NO and NO2, are generated and found in the process exhaust gas.  Depending on the amount of NOx present, a typical Heil NOx scrubber includes hoods/covers, ductwork, multiple Heil Model 730 Vertical Countercurrent Packed Bed Scrubbers in series, recirculation systems, multiple chemical addition systems, tanks, fan(s), stack, instrumentation and controls


HEIL also provides emission control systems for many other metal finishing operations below:

  1. Galvanizing
  2. Cleaning
  3. Chemical Milling
  4. Chemical Stripping
  5. Anodizing
  6. Electroplating
  7. Acid Etching
  8. Passivation
  9. Electroless Plating

Common emissions from the metal processing and finishing industry include, Hydrochloric Acid, Nitric Acid, Sulfuric Acid, Chromic Acid, Hydrofluoric Acid, Phosphoric Acid, and Alkaline emissions. HEIL Series 730 Counter-Current Scrubbers or Series 740 Cross-Flow Scrubbers are typically specified in these applications, and are often designed to achieve greater than 99% removal efficiency of acid gases and mists evolving from these processes.  

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Contact Information

HEIL Engineered Process Equipment Inc.

37000 Center Ridge Rd,
North Ridgeville, OH 44039

(440) 327-6051   Fax: 440-327-7088