New solar-biomass power generation system integrated a two-stage gasifier

A new solar-biomass power generation system that integrates a two-stage gasifier is proposed in this paper. In this system, two different types of solar collectors, concentrating solar thermal energy at different temperature levels, are applied to drive solar-biomass thermochemical processes of pyrolysis (at about 643 K) and gasification (at about 1150 K) for production of solar fuel. The produced solar fuel, namely gasified syngas, is directly utilized by an advanced combined cycle system for power generation. Numerical simulations are implemented to evaluate the on-design and off-design thermodynamic performances of the system. Results indicate that the proposed system can achieve an overall energy efficiency of 27.93% and a net solar-to-electric efficiency of 19.89% under the nominal condition. The proposed two-stage solar-biomass gasification routine exhibits improved system thermodynamic performance compared to that in one-stage gasification technical mode, and the provided heat resource is in a good match with the requirements for the biomass gasification procedure. Under given simulation conditions in this paper, the energy level upgrade ratio in the proposed two-stage solar-biomass gasification system for the introduced solar thermal energy is as high as 32.35% compared to 21.62% in one-stage gasification mode. Meanwhile, the daily average net solar-to-electric efficiency on the representative days reaches to the range of 8.88-19.04%, while that of 9.97-15.71% in one-stage model. The research findings provide a promising approach for efficient utilization of the abundant solar and biomass resources in western China and reduction of CO2 emission.