PACKED TOWER SCRUBBERS FOR SOLUBLE GASES
Packed tower scrubbers, sized to the gas you need to remove
Packed bed scrubbers for acid gases, ammonia, chlorine and other gases that dissolve or react in liquor. Tell us what is in the extract and a process engineer will size the bed, the liquor and the fan for your duty.
✓Bed depth, liquid-to-gas ratio and pressure drop calculated for your duty, and stated on the datasheet
✓Built in polypropylene, PVC, PVDF or GRP and wet-tested in our UK factory
✓Predicted outlet figures you can put in front of your regulator
Get a packed tower sized for your duty
Four fields to start. A process engineer will reply within 4 working hours to talk through your duty.
No obligation. Happy to sign your NDA first.
Is a packed tower right for your extract?
Built for gases that dissolve or react in liquor
Contaminated air rises through a wetted bed of packing while liquor flows down against it. The gas transfers into the liquor across a very large film surface, and the liquor chemistry neutralises it. For soluble gases, that gives high removal at a low pressure drop.
When we will suggest something else
Heavy dust or sticky mist will blind a packed bed. Most solvent vapours do not dissolve in water and need a different technology, such as activated carbon. If either applies, we will tell you before you spend anything.
Pickling, etching or plating? See acid fume scrubbers. Not sure which type you need? Start at wet scrubbers.
Real equipment
One of our packed towers on a recent install
How a packed tower works
From contaminated extract to clean discharge
Process extract
From reactor vents, tanks, baths or benches
Packed bed
Gas rises through the wetted packing, liquor falls against it
Sump and dosing
Recirculation pump, level and pH or redox control
Mist eliminator
Chevron blade or mesh pad stops liquor carry-over
Extract fan
Holds capture at the source
Clean discharge
To stack, within your limit
Spent liquor is bled under control. The datasheet states the bleed rate and what is in it.
Design envelope
Indicative ranges, then sized to your duty
| Parameter | Typical range |
|---|---|
| Duty range | 500 to 60,000 m³/h |
| Arrangement | Vertical counter-current or horizontal cross-flow |
| Gas velocity | Typically 1.5 to 2.5 m/s through the packed section |
| Liquid-to-gas ratio | Typically 1 to 3 litres per m³, set by duty |
| Packing depth | Typically 900 to 2,400 mm, in one or more beds |
| Body materials | PP, PVC, PVDF, GRP or 316L stainless |
| Removal efficiency | 95 to 99.5% on soluble gases, single stage |
| Pressure drop | Typically 400 to 1,200 Pa across the wetted bed |
| Mist elimination | Chevron blade or mesh pad |
Your own figures are calculated against your duty and issued on a datasheet before anything is built.
Why a Caldera packed tower
One team from sizing to commissioning
Sized, with the numbers shown
Bed depth, L/G ratio, packing type and reagent use are calculated from your inlet and required outlet, then set out on the datasheet.
Counter-current or cross-flow
Vertical counter-current for the most removal per metre of bed. Horizontal cross-flow where headroom is short.
Maintainable by design
Removable mist eliminator, access to the spray header, sample points and a drain-down one person can do.
What you receive
Evidence, not just equipment
- ✓Datasheet with inlet and predicted outlet concentration for each gas, liquor use, bleed and pressure drop
- ✓General arrangement drawing of the tower, fan, ducting and dosing
- ✓Factory wet test before the scrubber leaves our workshop
- ✓Signed commissioning record of setpoints and readings, ready for your permit file
To size a tower, we need
- What is in the extract, ideally a gas analysis
- Extract flow in m³/h and gas temperature
- Any dust or mist in the stream
- Your emission limit, from the permit or consent
- Space and services: footprint, water, drain, power
Missing some of it? Send what you have and we will help fill the gaps.
What happens when you ask
From enquiry to a commissioned tower
Tell us the duty
Four fields, plus flow and limits if you have them. NDA first if you need one.
Engineer reply in 4 hours
A process engineer comes back within 4 working hours to confirm a packed tower suits the duty.
Sizing and quotation
Datasheet, general arrangement and price in 10 working days.
Build, test, commission
Fabricated and wet-tested in the UK, then delivered and commissioned on your site.
Questions engineers ask us
Packed tower scrubbers: common questions
How do you size a packed tower?
From the gas and the limit. We set gas velocity through the packing, liquid-to-gas ratio, bed depth and liquor strength against your inlet concentration and the outlet you have to meet, then state all of it on the datasheet.
Counter-current or cross-flow?
Counter-current is the default: the cleanest gas meets the freshest liquor at the top of the bed, which drives the last few percent of removal. Cross-flow suits sites where headroom is short.
Which material should the tower be made from?
It depends on the gas, the liquor and the temperature. Polypropylene suits most acid and alkaline duties at moderate temperature. PVDF handles higher temperatures and stronger oxidisers. We set out the choice and the reason on the datasheet.
What removal can I expect?
Typically 95 to 99.5% on soluble gases in a single stage. Your figure is calculated for your duty and stated on the datasheet before anything is built.
Random or structured packing?
Random packing is the usual choice and tolerates some fouling. Structured packing gives a lower pressure drop in a shorter bed. Read our guide to packing types.
How much does a packed tower scrubber cost?
It depends on the flow, the chemistry and the materials. Send the duty and you will get a sized quotation with a datasheet in 10 working days.
Tell us what is in your extract
Send the gas, the flow and the limit you have to meet. We will tell you whether a packed tower will do it, and how big it needs to be, before anyone talks about price.
Request a quote Engineer reply within 4 working hours · hello@caldera-technologies.com