Membrane-Sorbent Hybrid System for Post Combustion Carbon Capture

The electricity produced from fossil fuels is essential to the worlds prosperity and security. On the other hand, increasing atmospheric CO2 concentration caused by the fossil fuel combustion are causing concerns regarding global warming. Although there are several methods for separating CO2 from the flue gases at existing coal-fired power plants, all of them have significant drawbacks, including loss of efficiency and increased capital and operating costs that dramatically increase the cost of electricity. TDA Research, Inc. (TDA), in collaboration with Membrane Technology Research Corporation and the University of California, Irvine are developing a low cost, high capacity sorbent that will integrate into a membrane-sorbent hybrid post-combustion carbon capture system to remove CO2 from coal-fired power plant effluents. In Phase I, we optimized the sorbent to meet the needs of the application. Our preliminary analysis results indicate the sorbent system operated in a concentration swing mode will have a significantly lower cost than an equivalent membrane system, increasing the economic viability of the carbon capture process. Sorbent improvements also enabled lower oxygen transfer rates from the boiler air intake side to the flue gas side. The process simulation suggested a plant efficiency of 29.74% for the hybrid system which is well above that can be achieved by the state-of-the-art amine scrubbing technology and the CO2 capture cost is estimated to be less than $42.2 per tonne on 2007 $ basis. In our Phase II work, we will work on further enhancing the CO2 capacity of the sorbent, while further reducing their oxygen affinity. We will assess the impact of critical parameters at bench- scale and carry out adsorption/desorption cycles (a minimum of 10,000 cycle test). We will then assess the performance of an integrated 2 to 5 scfm unit in the field using actual coal-derived flue gas. We will carry out the process simulation work and evaluate the techno-economic viability of the new CO2 capture technology retrofit to the existing pulverized coal power plants using the methodology described in NETLs Carbon Capture and Sequestration Systems Analysis Guidelines. CO2 is a major greenhouse gas and the most dominant source for the anthropogenic CO2 emissions. It is a by-product of the combustion of fossil fuels, in particular burning coal for generating electricity. The proposed technology will provide a cost effective way to control CO2 emissions from the existing and new coal-fired power plants. There will be a large market when legislation limiting or taxing carbon emissions is put in place.