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CO2 capture and storage

CO2 capture is performed on the three types of systems: IGCC (Integrated Gasification Combined Cycle), conventional thermoelectric power generation and oxygen combustion (oxy-coal-combustion). In each of the three types of systems, the following capture technologies are associated respectively: pre-combustion, post-combustion and oxy-combustion.

With regard to pre-combustion capture, the preparation process has been developed and oxidative barrier or ceramic Palladio based membranes have been characterized, for the separation of hydrogen in water-gas shift processes on synthesis gases.

The objective is to obtain lower costs and, in terms of purity and flow of hydrogen permeate, performance comparable with the international target. In particular, in addition to a series of factors which limit the reduction of the thickness of the palladium layer, issues related to the scale up of the preparation process of the membrane have been analyzed.

Furthermore, there has been collaboration in a European project on integrated gasification combined cycles (IGCC) evaluating degradation mechanisms of materials that constitute the coating of the hot parts of the latest gas turbines, which in this case are subjected to aggressive operating conditions.

For the post-combustion capture, a CO2 sorption unit (and desorption) has been developed from the flue gases based on chemical absorption with amines anchored to a solid support (solid sorbent).

Designed from a concept developed by RSE, four of these units are the central component of a pilot plant for CO2 capture in an advanced stage of implementation, which were installed by 2011 in a power plant fueled by coal.

The pilot plant will operate in batch and will be able to handle a flue gas flow rate of 100 Nm3/h. This innovative technology, compared to the conventional process based on amines in aqueous solution, does not present the typical drawbacks (corrosion of materials, formation of foams, oxidative degradation of the amines) and, thanks to the lower thermal energy requirement in the regeneration phase, allows recovery of about 3 percentage points of net electrical efficiency of the plant.

Within the scope of oxy-combustion and pre-combustion technologies, RSE activity is preparatory to the development of a membrane characterization technology in the laboratory for the separation of oxygen from the air. The membrane samples are initially provided as part of an agreement with a prestigious German research center. It is believed that the use of this technology will increase the net electrical efficiency of an IGCC plant, when compared to the traditional cryogenic plants, by 1 to 2%.