Process and operation

The process



Gas upgrading

Biogas must be upgraded for contaminant levels (H2S, VOC, other) before conversion to biomethane. The system uses two or more activated carbon beds in dual configuration reactors in order to ensure continuity and effectiveness of the process.


Biogas upgrading:
Separation of methane and CO2

Based on vacuum pressure adsorption technology, operating at ambient pressure with low energy consumption, the biogas flows in several reactors containing adsorbents that capture CO2 and moisture and produce biomethane with high CH4 content (> 97%).


of biomethane and CO2 from the exhaust gas stream

The biomethane is cooled and converted into BIO-LNG via a Linde cycle without the use of external refrigerants (e.g. nitrogen). A fine purification stage removes the CO2 still contained in the biomethane to make it compliant with liquefaction regulations.


Tank and calibrated unloading system

Structure of our liquefaction plant


Plant sizes and production quantities

The “Green Line Liquid” solution can be modularly extended to any biogas production volumes. We are thus creating a standard solution to ensure the supply of spare parts and therefore can provide a safe operation.

Plant size
(equivalent power in kWel)*
Biogas production
(Nm³ per hour)**
Biomethane production
(Nm³ per hour)
Bio LNG production
(t per day)
Bio-CO2 production
(t per day)
500 240 135 2,3 4,1
700 320 175 3,0 5,5
1.000 480 265 4,5 8,2
1.400 640 355 6,0 10,9
1.700 800 445 7,5 13,7
2.000 950 525 9,0 16,2
4.000 1.900 1.050 18,0 32,4

*We can supply equipment for any production quantities.
**Biogas stream at a methane content of 55.5%.

Our partner

The technology is produced by our partner Ecospray that is based in Italy. Ecospray began operating a facility in late 2019 that pretreats landfill gas, upgrades it to biomethane, and liquefies the biomethane into bio-LNG. The plant is designed for a production capacity of one ton of bio-LNG per day.

Customer testimonials

“The consulting, planning and implementation with RUHE Biogas was super, and after a short time we could already see the positive effects in the entire biogas process.”

Gregor Gerwin, Bioenergy Gerwin Produktions GmbH & Co.KG, 49692 Cappeln

“Especially when it comes to marketing the bio-LNG, RUHE Biogas’ expertise and transparency has helped me a lot to realize the true value of my biogas.”

Dirk Huster-Klatte, HK Bioenergie GmbH, 49688 Lastrup

“Kunibert Ruhe already sold us a biogas plant back then, and we are still very satisfied today. Now we are starting bio-LNG production with RUHE Biogas – for us there is no better partner.”

Bernhard Siemer, Josef Siemer Biogas Verwaltungs GmbH, 49429 Visbek

You want to learn more about our technology?

We would be pleased to support you in the preparation of a feasibility study. This includes a profitability calculation based on your substrate mix, gas composition, vessel volumes, and energy sources used.