Frequently asked questions
Short answers about our technology, the plant and where things stand.
What does Cairos do?
Cairos develops a catalytic methanation plant that produces renewable methane from biomass syngas, biogas, sewage gas or CO₂ together with renewable hydrogen. The methane can be fed into the existing gas grid and used like natural gas. Cairos is a spin-off project of Montanuniversität Leoben in Austria.
What is methanation?
Methanation is a chemical process in which carbon monoxide and carbon dioxide react with hydrogen on a catalyst to form methane. Methane is the main component of natural gas, so renewable methane can use the same pipelines, storage facilities and appliances.
Which input gases can the plant process?
Gasification gas and pyrolysis gas from biomass with steam or hydrogen, as well as biogas, sewage gas and CO₂ together with renewable hydrogen.
What is the difference between Bio-SNG and Renewable Natural Gas (RNG)?
Bio-SNG (synthetic natural gas) is made from solid biomass such as wood residues or straw, which is first gasified or pyrolysed into syngas. Renewable Natural Gas (RNG) is made from biogas, sewage gas or CO₂ together with renewable hydrogen. Both are renewable methane and can be used like natural gas.
Is CO₂ separation needed?
It depends on the route. With biomass syngas and steam (Solution 1), CO₂ is separated after methanation, for example by membrane separation or amine scrubbing. If renewable hydrogen is added (Solution 2), the CO₂ is also converted into methane and the gas reaches grid quality without CO₂ separation.
How big is the plant?
One module produces 2 MW of renewable methane, approximately 210 Nm³ per hour. The process equipment fits into two 20-foot standard containers, with the reactor and dry cooler mounted outside. Several modules can be combined, for example to 4 or 6 MW.
Has the technology been tested?
Yes. Cairos has operated three plants with 2, 20 and 200 kW. At the 200 kW pilot plant in Bruck an der Leitha, Austria, renewable methane of grid injection quality was produced from biogas and hydrogen. Validation with real tar-laden pyrolysis and gasification gases is ongoing.
What happens to the reaction heat?
Methanation releases heat. A thermal oil circuit removes it from the reactor and makes it usable. Depending on the input gas, a 2 MW module provides between 208 and 513 kW of usable heat.
Is the technology protected?
The technology is patent pending.
How can I get in touch?
Send us an email at office@cairos-energy.com. We look forward to hearing from potential partners, plant operators, funding bodies and investors.