Pilot-Scale Demonstration of New Compact CO2-Capture Technology at Elevated Pressures, and Design of Large-Scale Demonstration

Abstract

Compact, and lightweight solvent-based CO2-capture technology is developed. The technology has undergone pilot-scale demonstration and extensive testing. The aim of this research is to systematically quantify the effects on the process variables associated with pressurized CO2-capture of flue gas streams or other process streams, encompassing both low and high CO2 concentrations. The objective is to verify the technology and to obtain the data necessary for the design of a large-scale demonstration plant, capable of capturing CO2 under real operational conditions. Results from four months of operation of the pilot are presented. The novelty of the technology lies in the CO2 absorption aspect of a solvent-based capture technology, utilizing static mixers and separators for contacting the gas and liquid phases. Consequently, the pilot scale absorption unit has been integrated into an existing solvent regeneration system. The solvent utilized in the demonstration is a 30 wt% monoethanolamine (MEA) solution. Pressurized capture is benchmarked against previous research conducted using the same regeneration unit but previously done with a conventional atmospheric absorption column. The research project has performed extensive testing under atmospheric conditions, yielding substantial amounts of comparable data between conventional atmospheric CO2 capture and the new technology both at atmospheric and pressurized conditions. The results show a greater than 95% CO2 capture rate both for low (2.5 vol%) and high CO2 concentrations (10 vol%). Further, the testing shows significant improvement of mass transfer of CO2 between the phases, and reduced size requirements both from a physical aspect related to dimensions of gas piping, but also with regards to the size of the absorption equipment (i.e., Mixer, separator, and piping in between those two elements). The results obtained have been sufficient to design a large-scale demonstration plant, and dimensions, size, cost, energy requirement and OPEX considerations of a full-scale system will be presented. The novelty of the technology revolves around developing a compact CO2-capture system that can be retrofitted into facilities that has existing emissions points, but most importantly, being able to enable CO2 capture on offshore installations that is not suitable for conventional technologies. The technology is likely to provide a significant cost reduction from a CAPEX perspective due to the reduced size and weight. Capturing CO2 in a compact way at pressurized conditions is likely to add great benefits. Gas turbines manufacturers are developing methods of exploiting the pressurized exhaust after the compression stage upstream expansion to facilitate high pressure CO2-capture, while preserving the energy. The presented technology can be an enabler in this market and bring down cost, size and energy consumption for gas fired power production with CCS.