Biogas scrubbing
Remove CO₂ with water at near-atmospheric pressure.
- Bio-CNG and CBG plants
- Dairy and gaushala digesters
- STP digester gas
RESEARCH PARTNERSHIP / 03
Developed withIndian Institute of Technology Bombay#3 in engineering, NIRF 2025
Field validatedDelivered by Rispri Labs
Scrubbing, cooling, aeration.
One low-energy exchanger.
Rispri Labs delivers modular rotating-disk heat and mass exchangers, developed with IIT Bombay, for gas and biogas scrubbing, cooling towers, humidification, aeration and concentration. One platform, very low fan and pump energy, and no droplet carryover.
RESEARCH TO REALITYRispri Labs × IIT Bombay
IIT Bombay
What it means for you
Scrubbing, cooling and aeration in one exchanger.
<10 Pa
of fan pressure drop per stage, so fans use far less power.
No drive motor
The liquid flow itself turns the disks.
6 duties
Scrubbing, cooling, humidifying, aerating, stripping and concentrating.
Performance
Contact without the pressure drop.
Packed scrubbers, cooling-tower fill and air washers all force gas through a wetted bed, and pay for it in fan power, flooding, fouling and drift. Textured disks turning slowly through the liquid give a large, constantly renewed contact surface with almost no resistance to gas flow.
- <10Pa
- Gas-side pressure drop per rotor stage
- ~3m
- Pump head for liquid circulation
- 300–400m²/m³
- Contact surface packed into every cubic metre
- TRL 7–9
- Readiness across six applications
Figures are from the research team's field validation in operating conditions. Performance on your stream is confirmed in our laboratory before design.
Challenge and response
The problems this solves.
- 01The challenge
Packed scrubbers and fill burn fan power on high pressure drop.
How we solve itUnder 10 Pa per rotor stage keeps fan energy low.
- 02The challenge
Packing floods at high liquid flow and runs dry at low flow.
How we solve itWorks across a wide liquid-to-gas range, with no flooding or dry spots.
- 03The challenge
Packing and fill foul or scale, and the plant stops to clean.
How we solve itDisks are jet-cleaned in place while the unit runs.
- 04The challenge
Cooling towers and scrubbers lose droplets as drift.
How we solve itCarryover-free contact between gas and liquid.
How it works
The process, step by step.
- 1
Circulate
A low-head pump fills the reservoir under the rotors.
- 2
Rotate
The liquid flow itself turns the textured disks; no separate drive motor.
- 3
Contact
Gas or air sweeps the thin liquid film, exchanging heat and mass.
- 4
Clean
Online jets keep the disks clean without stopping the unit.
Use cases
Where rotating-disk gas scrubbing, cooling and aeration delivers.
Industrial gas scrubbing
Clean exhaust gases from kitchens, furnaces and power plants.
- Commercial kitchens
- Furnaces and boilers
- Power plant exhaust
Cooling towers and evaporative condensers
Cool with low fan power and no drift, on treated wastewater or seawater.
- Process cooling towers
- Evaporative condensers
- Evaporative pre-coolers
Humidification and air washing
Condition and clean air for buildings and processes.
- HVAC air washers
- Humidifiers and dehumidifiers
- Process air conditioning
Aeration and VOC stripping
Aerate wastewater and strip volatile compounds from groundwater.
- Wastewater aeration
- Groundwater VOC stripping
- Odour control
Stripping and concentration
Strip gases from liquids and concentrate solutions gently.
- Fruit juice concentration
- Milk concentration
- Seawater vaporisation
Comparison
How it compares.
| Factor | Packed tower / cooling-tower fill | Rispri solution |
|---|---|---|
| Gas-side pressure drop | High, and rises as packing fouls | Under 10 Pa per rotor stage |
| Liquid-to-gas range | Narrow; floods or dries out | Wide, without flooding or poor wetting |
| Drift and carryover | Needs drift eliminators | Carryover-free contact |
| Cleaning | Shutdown to clean or replace packing | Online clean-in-place jets |
| Materials | Fixed packing material | Disks in PP, PC, SS, Al or MS to suit the fluid |
| Scale-up | Custom tower for each duty | Modular rotor units added as needed |
Standards and regulations
Designed around the rules that apply to you.
We design each system to meet your consent conditions and the regulations for your sector, and our laboratory reports against them.
- IS 16087:2016Specification for upgraded biogas (Bio-CNG).
- Environment (Protection) Rules, 1986Stack emission limits for industrial exhaust.
- Energy Conservation Building Code, 2017Energy efficiency of HVAC and cooling systems in buildings.
- National framework on safe reuse of treated waterUse of treated wastewater as cooling-tower make-up.
Industries served
Built for the sectors that need it most.
- Waste-to-energy and biogas
- Hotels and resorts
- Dairy
- Power and refineries
- Food and beverage
- ETP, STP and ZLD plants
Why Rispri
Institute science. Industrial delivery.
Institute-developed technology
Built on patented and peer-reviewed research from our partnership with IIT Bombay.
Tested on your stream
Our accredited laboratory characterises your water or waste before design and verifies results after.
Engineering since 1999
The team that builds ETPs, STPs and ZLD plants across India takes each solution from pilot to full scale.
One accountable partner
Design, supply, installation, commissioning, operation and testing under one contract.
Questions
Frequently asked questions.
What can one exchanger do?
The same rotating-disk platform is configured for gas and biogas scrubbing, cooling towers and evaporative condensers, humidification and air washing, aeration and VOC stripping, and stripping or concentrating liquids. For effluent evaporation, see our ZLD evaporator.
Why is it so energy efficient?
Gas-side pressure drop is under 10 Pa per rotor stage, so fans draw very little power. The pump needs only about 3 m of head, and the liquid flow itself turns the disks, so there is no separate drive motor.
How ready is it for each application?
Wastewater vaporisation is at TRL 9 and biogas scrubbing at TRL 8. Cooling towers, seawater vaporisers, evaporative pre-coolers and evaporative condensers are at TRL 7.
How does it handle fouling and corrosion?
Disks are cleaned in place with water jets while the unit runs, and the disk material is chosen for the fluid: PP, PC, stainless steel, aluminium or mild steel.
Can it upgrade biogas to Bio-CNG?
Yes. It removes CO₂ with water at near-atmospheric pressure, so raw gas does not need compressing before scrubbing. Only the upgraded gas is compressed for Bio-CNG.
Research partnerships
More solutions from our partnerships.
THE NEXT STEP
Prove it on
your own stream.
Send us a sample or tell us about your site. We will test it, recommend a configuration and set up a pilot.
Request a pilot