Low-carbon power generation is receiving increasing interest due to climate warming concerns. The present article analyzes three low-carbon power cycles. The focus is on the feasibility of CO2 capture and opportunities for energy and mass integration. The first power cycle is a zero-carbon solid biomass fuelled multi-step gasification gas turbine power cycle involving multi-step solid biomass conversion, which is a more reversible process than one-step biomass combustion. The second zero-carbon coal-fired oxy-gasification steam chemical looping combustion gas turbine cycle benefits from: (i) improved cycle efficiency due to the increased reversibility of the chemical looping combustion process, (ii) cycle mass and energy integration due to the several recirculation loops involved, and (iii) extremely high CO2 capture rate due to the purity of the CO2/H2O mixture achieved at the outlet of a syngas reactor. The last power cycle - a biogas fuelled oxy-reforming fuel cell cycle - is superior in terms of the feasibility of CO2 capture, i.e. CO2 is captured from CO2-enriched streams, and due to the utilization of renewable biogas, negative net CO2 atmospheric emissions are achieved. It is concluded that high CO2 capture rates are feasible from pressurized CO2-enriched streams comprising either water or hydrogen, thus necessitating oxy-fuel power cycles. Opportunities for mass and energy integration are found to be greater in systems involving closed mass and energy recirculation loops. The discussions also emphasize that low-carbon power cycles could achieve minimized exergy losses by applying more reversible energy conversion processes.
Influence of manufacturing process and heat treatment on microstructure and mechanical properties of 12%Cr heat resistance martensitic steels has been discussed. These steels are used for elevated temperatures applications like: heat and power plants, chemical and petrochemical installations. Some cases of manufacturing mistakes of steam pipelines and turbine blades had been presented. These mistakes led to incorrect microstructure resulting in reduced lifetime and insufficient reliability of instalations.
PL
W pracy przeanalizowano wpływ procesów wytwarzania i obróbki cieplnej na mikrostrukturę i właściwości mechaniczne martenzytycznych stali żarowytrzymałych zawierających 12% chromu. Stale te stosowane są do pracy przy podwyższonych temperaturach w przemyśle energetycznym, chemicznym i petrochemicznym. Przedstawiono przypadki błędów w procesie wytwarzania rurociągów pary i łopatek turbin, które spowodowały niewłaściwą strukturę, a następnie skrócenie czasu eksploatacji i obniżenie niezawodności urządzeń.
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