Solar-aided power generation in biomass power plant using direct steam generating parabolic trough collectors

Abstract

Parabolic trough collectors may be used to increase the temperature of a heat transfer fluid flowing inside absorber tubes. A method of solar-aided power generation in thermal power plants is using heat transfer from the high-temperature heat transfer fluid for feed water heating. In doing so, less steam is extracted from steam turbine, and power output is increased. This paper investigates an alternative method of solar-aided power generation that uses direct steam generating parabolic trough collectors for feed water heating in a small biomass power plant. Such a power plant consists of an open feed water heater, which is more commonly known as deaerator due to its capability to remove dissolved gases from feed water. Feed water heating by solar energy in this power plant is more easily implemented by using parabolic trough collectors with direct steam generation than parabolic trough collectors with a heat transfer fluid. The proposed integration of parabolic trough collectors into a biomass power plant requires the supply of saturated steam from parabolic trough collectors to the deaerator. The steam quality reaches the maximum value when the direct normal irradiance is maximum. The performance of this system depends on the average value of effective direct normal irradiance. Simulation results show that there exists the optimum extracted steam pressure, which results in the maximum electrical energy generated by the power plant.