Nordsol technology for bio-lng from biogas
The Nordsol iLNG technology is essentially the use of conventional and proven technologies applied into a less complex process scheme. Biogas treatment and liquefaction are highly integrated in a compact, energy efficient system that is optimized for bio-LNG production from biogas. This makes small-scale bio-LNG production economically viable.
Biogas treatment
Methane in the biogas is separated from the CO2, water and other contaminants. The resulting biomethane needs to be very pure. Too high a concentration of contaminants can disrupt the liquefaction process. Plus, it results in a high-quality end product.
Biomethane liquefaction
Under atmospheric pressure, biomethane liquefies at -162°C. It makes liquefaction a complex process. The challenge is to prevent residual contaminants from freezing. This would disrupt the process and cause damage to equipment.
Bio-CO2 liquefaction
Integrated CO2 capture and liquefaction is unique to the Nordsol bio-LNG production technology. This step further improves the carbon intensity (CI) of bio-LNG. Depending on the feedstock, the CI could even become negative.
Biogas vs. natural gas
The technology for large-scale fossil LNG production has been around for decades. However, it cannot be used for small-scale, decentralized production of bio-LNG from biogas. Nordsol has reinvented the process of making LNG by carefully considering the key differences between natural gas and biogas:
- Required capacity of the installations
- Fluctuations in biogas composition and flow
- Complexity of the biogas composition
- Importance of energy management for economic viability
Biogas vs. natural gas
The technology for large-scale fossil LNG production has been around for decades. However, it cannot be used for small-scale, decentralized production of bio-LNG from biogas. Nordsol has reinvented the process of making LNG by carefully considering the key differences between natural gas and biogas:
- Required capacity of the installations
- Fluctuations in biogas composition and flow
- Complexity of the biogas composition
- Importance of energy management for economic viability
Biogas treatment using enhanced membrane technology
Nordsol solely utilizes membrane technology to remove carbon dioxide and any water. In just one energy-efficient step this separation process creates ultra-pure biomethane that’s ready for liquefaction. The key advantage is that no amine treatment with its high heat demand or pressure-swing adsorption units are needed.
Standard membrane technology is enhanced by sweeping the permeate side of the membranes with flash gas from the liquefaction unit. This improves the performance of the membranes and reduces residual CO2 in the retentate more than 10 times.
Standard membrane technology is enhanced by sweeping the permeate side of the membranes with flash gas from the liquefaction unit. This improves the performance of the membranes and reduces residual CO2 in the retentate more than 10 times.
Robust biomethane liquefaction
The liquefaction process is based on methane expansion and flash cooling. A major benefit of this process is that it is robust and easier to control than alternative processes. By creating conditions under which the methane has supercritical properties, the temperature in the heat exchangers can be higher than usual. This leads to less chance of residual carbon dioxide (or other residual contaminants) freezing out at this stage.
A three-phase separator ensures a constant and guaranteed quality of the bio-LNG. The device separates substances in different phases (solid, liquid, gas) from each other. This removes even the last impurities from the bio-LNG. Gas that flashes off during liquefaction is used to sweep (or purge) the membranes in the gas treatment step.
Integrated bio-CO2 liquefaction for a low CI index and zero methane slip
A bio-LNG plant based on Nordsol technology has a low carbon intensity (CI) index. This is a result of the energy efficiency of the plant and the integrated CCU facility. By capturing, liquefying, and reusing the removed carbon dioxide from the biogas, the CI index can even become negative.
In addition, any residual methane in the CO2 gas stream is fed back to the membranes rather than vented. It is a closed system with zero methane slip.
Key advantages of the iLNG technology
- High energy efficiency through smart integration
- Low carbon intensity and zero methane slip
- No adsorbents, solvents or heat demand
- Continuous and robust process avoiding freeze up issues
- Integrated CO2 liquefaction
Is your biogas ready for bio-LNG?
Are you interested in learning more about the possibility to produce bio-LNG from your biogas ? Click the button below and send us your information. We will contact you as soon as possible.
Is your biogas ready for bio-LNG?
Are you interested in learning more about the possibility to produce bio-LNG from your biogas ? Click the button below and send us your information. We will contact you as soon as possible.
