In this paper the results of the thermodynamic analysis of the oxy-combustion type pulverized bed boiler integrated with a hybrid, membrane- cryogenic oxygen separation installation are presented. For the calculations a 600 MW boiler with live steam parameters at 31.1 MPa /654.9 oC and reheated steam at 6.15 MPa/672.4 oC was chosen. In this paper the hybrid membrane-cryogenic technology as oxygen production unit for pulverized bed boiler was proposed. Such an installation consists of a membrane module and two cryogenic distillation columns. Models of these installations were built in the Aspen software. The energy intensity of the oxygen production process in the hybrid system was compared with the cryogenic technology. The analysis of the influence of membrane surface area on the energy intensity of the process of air separation as well as the influence of oxygen concentration at the inlet to the cryogenic installation on the energy intensity of a hybrid unit was performed.
This article describes a thermodynamic analysis of an oxy type power plant. The analyzed power plant consists of: 1) steam turbine for supercritical steam parameters of 600 °C/29 MPa with a capacity of 600 MW; 2) circulating fluidized bed boiler, in which brown coal with high moisture content (42.5%) is burned in the atmosphere enriched in oxygen; 3) air separation unit (ASU); 4) CO2 capture installation, where flue gases obtained in the combustion process are compressed to the pressure of 150 MPa. The circulated fluidized bed (CFB) boiler is integrated with a fuel dryer and a cryogenic air separation unit. Waste nitrogen from ASU is heated in the boiler, and then is used as a coal drying medium. In this study, the thermal efficiency of the boiler, steam cycle thermal efficiency and power demand were determined. These quantities made possible to determine the net efficiency of the test power plant.