Approach of the Chemical Research Group

CO2 capture and storage (CCS) entails CO2 (a greenhouse gas) capture from fossil fuel combustion gas emissions from large emission sources such as electric power plants and factories, and subsequent containment of the captured CO2 into geological formations for storage or sequestration.

Current CO2 capture costs from emission sources are estimated to be about 60% of the CCS costs. Therefore, reduction of CO2 capture costs is an important aspect for practical application of CCS.

The Chemical Research Group studies various CO2 capture technologies, with a special focus on chemical absorption, membrane separation, and adsorption methods that have generated significant outcomes for the progress of worldwide research in this particular field. Materials development, processing, and system investigation are conducted in the group.

We developed innovative chemical absorbents under the Cost Saving CO2 Capture System by Utilizing Low-grade Waste Heat (COCS) project that enabled a CO2 capture energy consumption of 2.0 GJ/t-CO2 and CO2 regeneration from the absorbents at temperatures of less than 100°C that are lower than the required temperature of 120°C as featured under the CO2 Ultimate Reduction in Steelmaking Process by Innovative Technology for Cool Earth 50 (COURSE 50) project in the steel-making industry.

One of the outstanding developed absorbents was selected for application in a commercial CCS plant owned by a private Japanese company.

By developing molecular gate membrane technologies to selectively capture CO2 from H2-containing pressurized gases such as that in the integrated coal gasification combined cycle (IGCC), we are aiming for a CO2 capture cost target of 1500 JPY/t-CO2 by 2015.

Our investigations demonstrated the excellent separation performance of new types of dendrimer/polymer hybrid membranes for separating CO2 from CO2/H2 gas mixtures. Recently, we succeeded in further improving the separation performance by modification of polyvinyl alcohol (PVA) polymer materials; the target separation performance (CO2 permeance = 3 × 1010 m3/(m2·s·Pa); CO2/H2 selectivity = 125) was obtained at 0.7 MPa. RITE and three private companies have established a joint research association for developing membrane modules and separation systems for practical application.

Based on our technologies, including the development of RITE-solvents, we are also investigating solid sorbents for CO2 capture to efficiently reduce energy costs and methods for evaluation of the CO2 capture process. We are currently examining the synthesis of novel solid sorbents capable of achieving a 1.5 GJ/t-CO2 for regeneration energy. We have successfully developed a RITE-solvent-based solid sorbent that can be regenerated at low temperatures. Evaluation for practical use is now underway.

As mentioned above, we are promoting innovative CO2 capture technologies, thus establishing the foundations for the next generation, while developing practical technologies that are acceptable to industries.

Moreover, we have developed seed technologies such as CO2 separation by zeolite membranes, H2 separation by palladium membranes, a hybrid CO2 capture system that combines the membrane technology with chemical sorption processes, and baroplastics that have low-temperature flow under high pressures for various purposes. More specifically, the membrane/absorption hybrid CO2 capture technology has been used in a private company.

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