An accelerated generation of CO2, initiated by the industrial revolution, has amplified the greenhouse effect on the planet, distorting the equilibrium to which the existing species are adapted to. Due to continuously increase of energy demand, the fossil fuel power plants, as the main CO2 source, will remain the main energy source for a long time. Considering this, advanced technological achievements in CO2 emissions reduction are highly required. An appropriate solution is the carbon capture and storage (CCS), especially for the post-combustion power plants where a cost-effective retrofit can be managed. Herein, a CO2 capture system for the post-combustion natural gas combined cycle (NGCC) power plants is investigated, especially because of a visible shift from coal to natural gas power plants due to the lower price of natural gas and reduced CO2 emissions. As the CO2 concentration in NGCC flue gas is estimated to 5 vol%, the CO2 capture material must have a high affinity towards CO2, thus the amine-based materials are considered very suitable. The CO2 scrubbing in aqueous alkanolamines have been researched for more than 50 years, however, there still persists the drawbacks like energy penalty, corrosion, oxidation and loss of the active material. Considering this, we have developed a new solid sorbent based on high density aminosilane grafted (covalently bonded) on silica with a large pore volume, such as pore-expanded MCM-41. The main features of the solid sorbent are 1) high stability in the presence of high concentration of oxygen and CO2 in both sorption and desorption processes; 2) enable regeneration in pure CO2 in a temperature range of 120-140 oC; 3) high capacity of CO2 capture in a wide range of CO2 pressures; 4) fast kinetics of CO2 adsorption even at very low CO2 pressures (< 1kPm). The developed sorbents can be applied in different industrial processes for Capturing CO2 and providing pure CO2 for utilization or storage, such as nature gas power plant, coal or biomass based power plants, cement plants, chemical plants. It can be also applied for CO2 capture from air, or CO2 rich air. It can increase the energy efficiency and lower the cost comparing to conventional amine process.
In this project, we together with our industrial partner Fjell Technology Group (FTG), Norway aim to optimize the post-combustion CO2 capture where CO2 will be captured by novel polyethylenimine (PEI)/carbon low temperature spherical pellet as solid sorbents. It will be effectively integrated with the dual fluid bed reactor system and process to achieve 6-8% efficiency penalty and 25-30% cost reduction compared to current technologies. The current study includes development of chemically- and mechanically stable PEI/carbon spherical pellet as low temperature solid CO2 sorbents, 50 hour of continuous CO2 capture in a internally interconnected fluidized bed (IIFB) prototype reactor system, which is combination of bubbling bed and riser reactor, and complete- and integrated process simulation together with techno-economic evaluation. The chemically- and mechanically stable low temperature solid CO2 sorbents on will be developed by anchoring PEI into highly porous carbon spheres, with high CO2 capture capacity, fast kinetics and low adsorption heat. The novel IIFB reactor will effectively utilize the PEI/carbon spherical CO2 sorbents for continuous CO2 capture, thereby decreasing operating and initial investment cost. A process of natural gas combined cycle (NGCC) power plant with new integrated post CO2 capture will be designed and evaluated where the CO2 capture and regeneration are highly integrated in the process, and the development of low temperature solid CO2 sorbents and the new reactor are integrated in the process development, to achieve highest energy efficiency and low cost.