Demonstration unit for carbon capture

Through an EUDP-supported project, ARC, together with DTU, Pentair and Rambøll, is investigating how carbon capture is best connected to waste incineration, and whether it can be made energy-neutral by using heat energy from the carbon capture process for district heating.

Carbon capture is particularly interesting in relation to energy utilization of waste, as it is possible to capture large amounts of biogenic CO₂, whereby a unit can help to actively lower the total amount of CO₂ in the atmosphere. Roughly two-thirds of the CO₂ discharge from Amager Bakke consists of biogenic CO₂.

The challenge of connecting carbon capture for a waste-to-energy plant is, however, that there are many variations in the composition of the flue gas that come from energy utilization of waste, as the waste brought to the plant is varied. This means that a carbon capture unit connected to waste energy must be able to handle changes without affecting efficiency.

The tests on a small pilot unit in 2021-2022 were very promising in terms of the efficiency of capture. This is why the partners behind from late 2023 have commissioned a larger demonstration unit with a capacity of capturing up to 4 tons daily. The unit has verified the results obtained from the pilot unit. Fewer solvents have been tested compared to the pilot unit. However, the tests conducted have been for longer periods.

The captured CO₂ is of food-grade quality and has been pressurized and converted into a liquid. It is temporarily stored in a storage tank outside Amager Bakke before being periodically collected and transported by Linde Gas. The captured CO₂ has, among other uses, been supplied to a greenhouse in Stevns. Like all other greenhouses, it uses CO₂ to accelerate and enhance the growth of vegetables, significantly improving yield in a shorter time. Traditionally, greenhouses have produced CO₂ using gas-fired boilers, and the goal is to phase out the use of fossil gas.

This is the first time that CO₂ captured at a waste-to-energy plant has been sent for industrial use.

The demonstration unit resembles in every way a full-scale unit, although of course it is much smaller.

You can read more about carbon capture, ARC’s project and results in the articles below:

Pilot-scale Post Combustion carbon Capture at Amager Resource Center (ARC) Denmark: Challenges and Experiences

The pilot unit for carbon capture was operational at ARC until April 2022. The aim was to test if CO₂ can be captured from flue gas from a waste-to-energy plant and gain practical experience with carbon capture technology. The pilot studies was the first of their kind at a waste incineration plant.

This research article summarises a number of the experiences gained from the project. Such experience is relevant to future experiments with carbon capture technologies.

Emission measurements and degradation of solvent from waste incineration plant Amager Resource Center (ARC), carbon capture pilot project

This research article deals with whether the completed carbon capture process at the pilot unit at ARC has led to any unwanted emissions.

CO₂ capture process takes place by capturing CO₂ in the flue gas with an amine-based solvent. The solvent is broken down over time due to impurities in the flue gas. Experience from the pilot unit at ARC shows that the breakdown can lead to unwanted emissions, e.g. from flue gas, and also consists of corrosion products. Installing a filter to clean the solvent of impurities fixed the problem.

A Call for Standards in the CO₂ Value Chain

The technology to capture CO₂ and then transport it to either underground storage or for use in PtX (as a basis for the development of green fuels) is ready to be implemented.

This research article points out that there is a lack of global harmonization of the framework for the entire value chain from capturing CO₂ until it has been transported further for storage or use. A standardization of the quality of CO₂ is particularly urgent. The higher the requirements, the higher energy consumption in the process of capturing and purifying CO₂. On the other hand, it becomes cheaper to transport and store. Coordinating this worldwide to reduce costs throughout the value chain is necessary. A CO₂ infrastructure and storage capacity across national borders is also required – as CO₂ does not respect national borders.

Solvent degradation and emissions from a CO2 capture pilot at a waste-to-energy plant – ScienceDirect

Degradation and emissions of amine-containing solvents from CO2 capture units are important to address as we are getting closer to full-scale deployment. This article describes solvent degradation and air emissions from CO2 capture with 30 wt% monoethanolamine (MEA) on the pilot unit treating flue gas from a ARC. The release of nitrosamines and nitramines was shown to be below the detection limit. Preliminary results showed that the installation of an acid wash removes gaseous degradation products from the depleted flue gas by up to 83% for MEA.

Results from pilot-scale CO2 capture testing using 30 wt% MEA at a Waste-to-Energy facility: Optimisation through parametric analysis – ScienceDirect

This article contains an overview of the data gained from the pilot unit. The pilot is fully automated, and the process control structure helps achieve multiple steady states at regular intervals. In addition, the pilot is capable of several configurations which can assist in optimising the energy required for solvent regeneration. The article discusses the base case configuration of the pilot unit by employing 30 wt% MEA as the solvent. Experiments were conducted to analyse the influence of reboiler duty, solvent flow rate, and gas flow rate on the pilot’s performance. The influence of these parameters on several aspects is discussed in detail, and recommendations for the optimal operation of such units are provided.

You can find out more about the project at EUDP´s website, and read more about the heat pump integration and net-zero-energy in Ebbe Hauge Jensen’s thesis at DTU from 2021