Until now, large and relatively expensive facilities have been needed to upgrade biogas to the quality of natural gas. However, DTI has now developed a unique plastic membrane that separates CO2 from biogas by a simple method. Neither chemicals nor large complicated facilities are required.
The underlying principle is that some plastic materials are able to retain specific gasses while allowing others to pass through. The idea is therefore to find a plastic type that blocks off either methane or CO2, thus separating the CO2 content of biogas.
- It’s actually quite simple, and the beauty of it is that the process consumes no energy. All it takes is lower gas pressure, which is needed anyway when the gas is released into the natural gas grid, explains Jens Christiansen, Head of Section at DTI, who heads off the project.
Promising plastic membrane prototype
The original project concluded in 2011. However, an additional allocation of EUR 0.2 million has been earmarked for DTI to develop the technology until the summer of 2013. Totax Plastic A/S is involved as a project partner during this phase.
- For Totax, this is an interesting project which allows us to expand our field of options via a combination of known production techniques, and introduces us to new materials. It’s also interesting to participate in developing products that will cover future energy needs, explains CSO and CMO Peter Michael Haugvik of Totax Plastic A/S.
- We’ll be looking into how to separate a greater volume of CO2. Our aim is that the gas will only contain a very low percentage of CO2. We can probably achieve this goal by combining plastic membranes with tiny ceramic particles, called zeolites, which resemble porous sand. The particles allow CO2 to penetrate while methane is retained, explains Jens Christiansen. He hopes that the combination of plastic and zeolites can upgrade the gas to a sufficiently high
Today, DONG Energy A/S uses conventional scrubber technology to clean biogas, but has responded positively to the new simple method which DTI is working to refine.
- If a membrane solution will reduce operational and investment costs, we’d definitely be interested, says Asger Myken, Project Manager of DONG Energy’s new biogas upgrading facility at Fredericia.
As a project partner, the Danish Gas Technology Centre is documenting the suitability of the gas for distribution through the natural gas grid.
In work with energy gases like natural gas, biogas, gasification gas or electrolytic gas, it is often relevant to determine the precise composition of the final gas or a gas at an intermediary step in the purification process. DTI offers to analyse gas samples and determine the precise composition of various energy gases.