Susana Almeida and Arne Gladis. Photo: Christian Ove Carlsson

Biogas upgrading for high-purity CO2 and natural gas distribution

State-of-the-art biogas cleaning and upgrading aims to remove CO₂ and impurities from biogas to allow for distribution and sale into the existing natural gas grid as biomethane.

Today, high-purity CO₂ from upgrading of biogas is emitted as a waste product into the atmosphere. As first objective, this project focuses on turning the otherwise emitted CO₂ into a valuable green product, namely BioCO₂, which can be sold as an additional commercial product by the biogas producer. The quality of the BioCO₂ should be high enough for food, biofuel, medicine production and welding purposes.

The second objective of the project is to reduce the energy consumption of the amine adsorption-based biogas upgrading technique by up to 45 % by introducing new additives to the process. This will contribute towards improving the financial viability of biogas production.

The project will include i) benchmarking of the envisaged technology from both an energy and cost perspective through analysis of data from existing biogas upgrading plants and ii) experimental testing of the performance of the new additives.

The experimental work is done in both lab-scale and pilot-scale to investigate the mass transfer and reaction kinetics in the MEA-CO₂-H₂O-additive system. Based on the experience from the experimental campaigns, a mobile demonstration test unit (MTU) is constructed. The MTU will be used to test the capability of the additive-improved amine upgrading technology to produce both biomethane and BioCO₂ at three industrial biogas production sites.

The project is a collaborative effort between CERE, DTU, Union Engineering A/S, and Dansk Gasteknisk Center and has a total budget of 14 million DKK. It is funded by the Danish Energy Agency’s Energy Technology Development and Demonstration Program (EUDP) and is scheduled to run from 2016-2023.

The BioCO₂ project has been in many different locations other than DTU:

Currently, the project operates the mobile test unit at Hashøj Biogas in Western Zealand. The plan is to stay until end of August 2022.