A HYBRID POWER GENERATION SYSTEM UTILIZING SOLAR THERMAL ENERGY WITH CO_2 RECOVERY BASED ON OXYGEN COMBUSTION METHOD

摘要

A CO_2-recovering power generation system utilizing solar thermal energy was proposed. In the system, relatively low temperature saturated steam around 200℃ is produced by using solar thermal energy and is utilized as the working fluid of a gas turbine in which generated CO_2 is recovered based on the method of oxygen combustion. Solar thermal utilization efficiency becomes considerably high compared with that of conventional solar thermal power plants in which high temperature steam near 400℃ has to be produced for steam turbines, and the requirement for solar radiation in the location in which the system is constructed can be significantly relaxed. The proposed system is a hybrid-type system using both the fossil fuel and solar thermal energy, and thus its capacity factor becomes very high. The fuel is utilized in an exergetically excellent way in the system, that is, is used for raising the steam temperature higher than 1000℃. The generated CO_2 is recovered by using oxygen combustion method, so that high CO_2 capturing ratio near 100% as well as no thermal NOx emission characteristics can be attained. It has been shown through simulation study that the proposed system has net power generation efficiency of 64.5% on the base of consumed fuel energy by using saturated steam with temperature 230℃, being higher than 48.3% compared with that of the conventional power plant with 43.5% efficiency.