Decarbonisation Technology - November 2022

DMX CO 2 capture technology: an industrial demonstration An innovative CO 2 capture absorption process technology offers improved performance and reduced energy requirements compared with existing solvent

Christian Streicher Axens

A ll scenarios anticipating carbon neutrality by 2050, led by those of the International Energy Agency (IEA), confirm the need to shift to cleaner energy systems to achieve net-zero emissions through a wide range of solutions. Among the transformations proposed for the energy sector, heavy industries and transport, carbon capture and storage is ranked among the top solutions to reach this goal. Carbon capture is thus due to play a fundamental role in achieving the Net Zero Emissions scenario in 2050: indeed, as stated in IEA’s 2020 Global Status of CCS report, “Without CCS, net-zero is practically impossible.” CO₂ capture by amine scrubbing is currently considered a suitable technology for sectors with large, fixed CO₂ emissions due to its robustness, adaptability, and capability of producing a highly concentrated CO₂ stream, suitable for transporting and storing or reuse. Some significant challenges need, however, to be addressed for the industrial deployment of this technology, among which reducing the process energy penalty is critical. Other challenges, such as limiting solvent and VOC emissions, long-term process stability and footprint reduction, also need to be addressed. The DMX Process technology presented in this article provides improved solvent formulation and process configuration to answer those challenges. Technology presentation The DMX Process is a CO₂ capture process developed by IFP Energies nouvelles (IFPEN), based on CO₂ absorption by a demixing

Gas treated

CO lean solvent

Decanter

Lean solvent

Up to 5 barg

Absorber

CO rich solvent

Stripper

Flue gas

Reboiler

Rich solvent

Lean solvent

solvent. The DMX Solvent consists of a mixture of two organic compounds in an aqueous solution which is demixing under certain conditions of temperature and CO₂ partial pressure. Figure 1 illustrates the main steps of the Process. The flue gas (or other types of gas) to be treated is contacted with the solvent in a counter-current absorber. The rich solvent from the absorber bottom is preheated in a lean/rich heat exchanger, which creates conditions for demixing of the solvent. This demixing allows phase separation in a decanter into a lean solvent phase which can be directly recycled to the absorber and a rich solvent phase fed to a thermal regenerator. The DMX Solvent has a high cyclic capacity (much higher than standard monoethanolamine (MEA), for instance), and only the CO₂- rich phase needs to be regenerated, which Figure 1 Typical process flow diagram of DMX technology