Foto: Martin Dam Kristensen

Modular plants to upgrade biogas

Friday 24 Mar 17
by Morten Andersen

MeGa-StoRE consortium

MeGa-StoRE (Methane Gas Storage for Renewable Energy) is a project in which three companies, Elplatek, NGF Nature Energy, and Green Hydrogen, collaborate with DTU Mechanical Engineering.

Elplatek produces electrocatalytic materials, for example those used in the project’s electrolysis plants, as well as catalytic materials for gas purification processes. In recent years, Elplatek has also produced surface solutions in connection with fuel cells.

Per Møller from DTU Mechanical Engineering is the project manager and initiator of MeGa-StoRE. The project is funded by the ForskEL programme under

From biogas to methane

The upgrading of biogas to pure methane is a two-step process.

The first step involves purifying the biogas from a large number of contaminants which may cause problems later in the process. Biogas contains far more contaminants than natural gas, which is why a new purification method has been developed in which toxic compounds (e.g. sulfides, oxidise mercaptans, and siloxanes) are converted into non-toxic compounds, which are removed regularly and readded to the degassed manure as useful nutrients. This process has made it necessary to develop new catalytic materials.

Following purification, the biogas is transmitted to step two, where a new catalyst triggers the reaction between the CO2 and hydrogen content of the biogas supplied from an electrolysis plant. This generates more methane—in addition to the methane already contained in the biogas. The project has succeeded in implementing this part of the methanization process with CO2 as a starting material in a single step, which is a breakthrough when it comes to upgrading biogas.

A new concept makes investing in the required upgrading technology affordable for the biogas sector.

A consortium composed of three companies and DTU Mechanical Engineering has developed technology capable of upgrading biogas to a quality equivalent to that of natural gas, as well as a new business concept.

“Unlike traditional energy plants, we’re focusing on plants designed as modules that fit into standard containers. This way, a biogas producer can get started with only a limited level of investment,” explains Karsten Bejder, Senior Scientist at Elplatek, which is one of the partners of the so-called MeGa-StoRE project (see fact box). Together with Professor Per Møller from DTU Mechanical Engineering, he has developed a biogas upgrading concept. Sebastian Villadsen and Christian Warm, both PhD students from DTU, also participate in the project.

“Our point of departure has been to focus not only on the technical functioning of the plants, but also on logistics and, not least, finance. The modular structure prevents the owner from investing capital in capacity which is not exploited. It facilitates moving modules to other places where they are needed more, to always ensure the highest possible contribution margin,” explains Karsten Bejder.

Upscaling on the agenda

The consortium behind the project has developed a modular plant, where biogas initially undergoes a purification process to remove impurities. The gas is then led to the actual plant where hydrogen is added. A special catalyst catalyses the reaction, converting the CO2 and hydrogen to methane.

The concept has been demonstrated at Lemvig Biogas, where a capacity of 24 m3 of upgraded biogas was achieved over a 24-hour period. The consortium is currently building yet another plant.

“The Lemvig plant has provided us with proof of concept, and now we must show that we can scale up things. The new plant is designed to process approx. ten times as much biogas,” says Karsten Bejder.

In addition to demonstrating the technology on a large scale, the new container is to serve as a model for a new business concept, where the plant is composed of modules to ensure flexibility and scalability.

“Biogas producers generally have plenty of space and ample room for a container-based solution on their site. At the same time, they can distribute investments over time. They can increase the size of the plant as their income rises,” says Karsten Bejder.

Generates income for suppliers

A way to minimize the costs of running the plants is to use standard components, and to establish the plant in standard containers originally developed for data centres—i.e. they are isolated and have elevated floors.

“Building modular systems is common when it comes to data centres. Depending on how needs develop, it’s easy to add or remove a number of modules. We want the upgrading of biogas to use the same approach,” says Karsten Bejder.

The concept is not only flexible manner in relation to the physical design, but also in relation to organization, he adds:

“A biogas producer can, of course, choose to own the plant himself, but there are definitely other options. For example, one or more operators can own a fleet of plants. This makes it possible to move plants to a different location which is more suitable at that time. It will further improve the possibilities of making money from the upgrade.”