The chlor-alkali industry produces basic commodity inorganic chemicals which are supplied to a wide range of final production industries, such as PVC manufacturing, sulphonation industries, textiles, pulp & paper and so on.

Producing inorganic chemicals inevitably involves the production of emissions and pollutant chemicals and that’s where AWS can help with its reliable and cost-saving solutions.

In this article you will find three different cases of chlor-alkali industries that relied on AWS solutions in different applications. Continue reading and discover how we solved filtration problems in this specific industry.


Process conditions

  • Gas flowrate: 12.000 Nm3/h
  • Temperature: 30°C
What needs to be filtered: NaOH solution mist from hydrogen gas

Technical solution

  • FiberwindTM filter with carbon fiberbed

Screens and flanges

Screens and flanges are supplied in AISI 316L, here below you can see a photo of the external cages still empty.

Filtering media

Our customer requested Carbon filter media for this specific application. Carbon filter is a matress wrapped around the element, unlike the usual glass fiber media which is winded as a rope.

The filter elements are working efficiently since years.
The foreseen lifetime of each candle is 7 to 10 years.


Process conditions

  • Gas flowrate: 5.100 Am3/h
  • Temperature: 18°C
What needs to be filtered: salts + moisture from chlorine gas.

Technical solution

AWS supplied a wet demister in FRP plus a set of Fiberwind filter elements with Titanium cage for the treatment of wet chlorine gas.


The Vessel has been constructed with FRP/Derakane material, painted in bright yellow and manufactured according to ASME VIII code div. 1 at full vacuum.

The vessel has been shipped safely via sea-freight from Italy to Canada.

Here below you can see some pictures of the vessel under construction and then packed for shipment.

Fiberwind filters

Screens and flanges are supplied in Titanium since this type of material is recommended in case of presence of corrosive salts & moisture in chlorine gas as alternative to screens fabricated in Derakane 470.

Titanium is very resistant against corrosion and the screens have much longer duration than standard FRP screens, which typically have a duration of 2-3 years from start-up and then they need to be replaced.

The candle filter media is made of special glass fiber rope.

APPLICATION: Dry chlorine line

Process conditions

  • Gas flowrate: 27 tons/hour max
  • Temperature: 40°C
  • Pressure: 10 bar(g)
What needs to be filtered: Sulphuric acid mist from chlorine gas.

Technical solution:

AWS supplied a set of Cyclones to be installed in a Chlorine industry.

These special devices separate chlorine gas from sulphuric acid droplets thanks to the intense centrifugal forces.

The separated acid mist flows down the surface of the inside wall, meanwhile the cleaned gas flows through the upper part of the droplet separator.

Design, construction, testing and acceptance procedure according to PED 97/23/EG. RX on 100% of the butt welding.

The codes and standards that will be followed for equipment supply are in accordance with all applicable codes and standards.

Vessel material: Carbon steel
Attachment parts material: Carbon steel

EUROPE - Corporate headquarter

AWS Corporation Srl.
Viale Padania n°10
24055 Cologno al Serio (BG)

  • Phone +39 035 4819888
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  • REA BG-392381 - C.F. e P.IVA 03328440247


AWS (Shanghai)
Room 908, No. 870 Maotai Road,
Changning district Shanghai