New membrane technology for reducing carbon dioxide emissions
The membrane-based separation of the greenhouse gas carbon dioxide from power stations and industrial facilities has been studied since January 2016 in a project funded by the Federal Ministry for Economic Affairs and Energy. Scientists from the Helmholtz-Zentrum Geesthacht (HZG), the Research Centre Jülich (FZJ) and the DVGW Research Centre at the Engler Bunte Insitute (EBI) in Karlsruhe are developing the membrane material and the technological methods for the project. The new technology is to be devised up to the pilot scale. Membrane testing under real conditions plays a vital role in the project. Polymer as well as ceramic membrane materials are under investigation. The selected materials preferentially absorb CO2 from the flue gas flow. If a pressure difference is applied, the CO2 concentrates on the low pressure side of the membrane.
The main objective of the new energy policy is for Germany to achieve a level of 80% renewable energy by 2050. In order to close the remaining gap as well as to compensate for fluctuating renewable production if necessary, conventional power stations will continue to provide energy using fossil-based fuels. The aim of the new MemKoR project ("Membrane Processes for Separation of Power Station Flue Gas Carbon Dioxide") is to minimize the release of the greenhouse gas CO2 into the atmosphere when burning coal and gas.
The objective to reduce anthropogenic climate warming to less that two degrees Celsius cannot be reached without CO2 separation. This necessity is indicated in reports by the German Environment Agency, the International Energy Agency (IEA) and the Intergovernmental Panel on Climate Change (IPCC).
With a sum of more than three million Euros, the Federal Ministry for Economic Affairs and Energy (BMWI) is funding the research into separating carbon dioxide produced by power stations and industrial facilities. These funds are available to the project consortium under the leadership of membrane researchers from Geesthacht for the coming three years.
Dr. Torsten Brinkmann, department head of the Institute of Polymer Research at the HZG, serves as coordinating scientist. Brinkman says of the project's goals: "Membrane-based separation of CO2 from power station flue gases is ideal for quickly and flexibly reacting to the changing flue gas flows in the now frequent partial-load operation. The modular structure of our membrane methods allows us to separate only partial quantities from the flue gas. This facilitates a simple adjustment to the scale of the material CO2 recovery and thus a system that is adjusted precisely to the needs."
While flue gases have already been filtered from nitrogen oxide and sulphur dioxide to a large extent, carbon dioxide separation is still a considerable research endeavour for the scientists. This particularly applies to the increase in efficiency, cost optimization and environmental compatibility of the different methods. The membrane-based separation as a relatively new method possesses advantages in contrast to conventional methods, such as chemical scrubbing.
Separation Behaviour in the Power Station Experiment
"We want to verify the long-term stability of our membrane materials, the membrane modules and the methodological technology on the pilot scale," explains Dr. Torsten Brinkmann. "For this task, we will equip our CO2 separation unit with up to fifteen square metres of membrane surface.The polymer membrane materials from Geesthacht and those made of ceramic from Jülich come into play here. We will then be able to test the influence of temperature, pressure, gas composition and dust on the separation behaviour of our membranes under real conditions at the Rhine Harbour Steam Power Plant of EnBW Energy Baden-Württemberg AG in Karlsruhe and at the Niederaußem Power Station of RWE Generation SE." The project group receives support from Linde AG in modelling the methods and in regards to questions of cost effectiveness.
The scientists are concerned with objectively evaluating the potential of membrane technology for CO2 separation, the process efficiency and the possible uses of CO2. Mainly, change of power station working conditions should be considered in times of energy transition. In the end, a completely new technology package should be created for membrane-based separation of CO2 from power station flue gas.