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The paper provides with a first assessment on the suitability of Pressure Swing Adsorption (PSA) as a valid option for Carbon Capture and Storage (CCS) in coal-fired power plants. A full-plant analysis of an Advanced SuperCritical (ASC) pulverized coal plant and of an Integrated Gasification Combined Cycle (IGCC) plant, operating with a PSA unit, is presented. The systems selected aim to represent the most diffused options for coalbased power generation, respectively in a post-and pre-combustion application of CO2 separation. The definition of the PSA process is tailored for the two different scenarios considered, starting from the adsorbent selected (zeolite 5A and activated carbon, respectively for post-and pre-combustion). The objective is to investigate the competitiveness of PSA with respect to the benchmark technology for CCS, namely absorption. In order to consider the different aspects measuring the effectiveness of a CO2 separation technique, the performance of the power plants is evaluated in terms of CO2 separation performance, energy efficiency and footprint of the technology. The post-combustion scenario analysis shows that PSA can be competitive with regard to the separation and the energy performance. PSA is able to match the CO2 separation requirements, and the relative energy penalty is slightly lower than that resulting from amine-absorption. Despite that, the footprint of the PSA unit demonstrates to be way larger than that related to absorption and unlikely acceptable. PSA in the pre-combustion scenario returns encouraging results, approaching the outcomes achieved with absorption both in terms of CO2 separation performance and plant energy efficiency. The footprint, even though significantly larger, appears to be reasonable for actual implementation.

Effective heat and power supply to offshore installations leads to environmental benefits, but the efficiency is often limited by requirements and constraints connected to the offshore environment. An exergetic analysis of gas turbines exhaust heat recovery on offshore platforms is performed to identify optimal approaches to produce heat and power. Two different configurations are presented, with heat delivery at two temperature levels and power production by an organic Rankine cycle (ORC). In one system (cascade), the high temperature heat is taken from the exhaust after the ORC, while low temperature heat is taken from the ORC condenser.Alternatively, high and low temperature heat is taken from the exhaust gas before the ORC feeds on the remaining exhaust thermal energy (series system). Four different working fluids (three siloxanes, one refrigerant) are considered. In addition, the exergetic effects of the heat loads and heat source temperatures are investigated. The results revealed that MM and R124 are the best working fluids for the cascade and series system, respectively. A recuperated ORC in the series

Global climate change resulting from the emission of greenhouse gases has become a widespread concern in the recent years. Carbon dioxide alone contributes roughly two-thirds to the enhanced greenhouse effect. Carbon capture and storage (CCS), an approach for mitigating potential global climate change, is widely known as a selected track towards sustainable application of fossil fuels. Technologies to separate and compress CO 2 from power plant flue gases are commercially available. Absorption, using monoethanolamine (MEA), is the most common technology applied to capture CO 2 from flue gas of fossil fuel power plants. However, the efficiency penalty induced by carbon capture within energy conversion systems poses a threat to the economic viability of these systems. The adsorption technology due to the ability to operate at moderate temperature and pressure, the increase of the capacity of CO 2 adsorption and the compliance with the environmental safety are the trickiest in the adsorbent design. The primary objective of this work was to design an adsorbent with ability of adsorbing large quantity CO 2 at efficient energy. A long chain polymer was grafted with a diamine to provide a large CO 2 anchoring site for carbamate formation, covering multiwalled carbon nanotubes (MWNTs) to enhance the surface area and pore volume. Thus, an advanced adsorbent was made after polycondensation of aspartic acid between 190°C-210°C in phosphoric acid medium and the use of dicyclohexylcarbodiimide (DCC) as the coupling agent; this resulted in long chain polysuccinimide (PSI) synthesis. A ethylenediamine (EDA) was grafted to the PSI to give a polyaspartamide (PAA), which, covering the MWNTs, has achieved an adsorbent with 100% EDA incorporation as showed 1 H NMR. The chemical surface of the PAA-MWNTs showed with FTIR analysis the primary amine group and the amide group as CO 2 anchoring sites and biodegradable bonds respectively. As evaluated via BET, the low surface area and pore volume of PAA have increased by 31 and 41 times respectively with the inclusion of MWNTs (8nm). Thus, the surface area, pore volume, and pore size of the synthesized adsorbent (PAA-MWNTs) were 60.4m 2 /g, 0.4cm 3 / respectively. Transmission electron microscope (TEM) analysis and the decrease of graphitized carbon as shown with Raman spectra have shown that the covering of MWNTs by the polymer PAA increased the diameter size from 8nm 2 adsorption using PAA-MWNTs as an adsorbent. The CO 2 th the use of TGA in order to evaluate the CO 2 adsorption capacity of the 2231 adsorbents. The PAA-MWNTs showed a higher CO 2 adsorption capacity of 70gCO 2 /kg compared to PAA, PSI, and MWNTs alone, where the adsorption capacity showed 46.17gCO 2 /kg, 26.90gCO 2 /kg, and 15.20gCO 2 /kg respectively.