Solar Thermal power generation systems

A hybrid power generation based on biomass gasification and concentrated solar thermal.

Investigation of optimal integration by pinch analysis.

Improvement of system efficiency by co-utilizing surplus heat and solar thermal.

Efficiency affected by composition and temperature of gasifying agent.

This paper describes the investigation of a hybrid power production system from biomass and solar energy. This paper suggests integration through heat exchanger network as a useful approach to obtain the synergy between biomass and solar. Biomass is first gasified in a bubbling fluidized bed (BFB) gasifier, and then syngas is used in a gas turbine. Excess heat exists in this sub-system and concentrated solar thermal process (CSTP) while there is a demand of steam for generating gasifying agent. Steam Rankine cycle exploits the heat created by these thermal streams to generate power while satisfying the steam demands. Thermodynamic performance was analyzed by process modelling with a semi-kinetic model of BFB gasifier and pinch analyses. The composition and temperature of gasifying agent showed some effect on the overall efficiency of the system. Higher overall efficiency of the system was achieved at higher temperature and higher O2 fraction in the O2-steam mixture as gasifying agent. The increase in thermal input from CSTP had positive effect on overall efficiency of the hybrid system until thermal input from CSTP becomes dominant against thermal stream related to the gasifier and the gas turbine.

Keywords

• Biomass gasification;
• Integrated gasification and combined cycle (IGCC);
• Semi-kinetic model;
• Concentrated solar power (CSP);
• Pinch analysis;
• HEATSEP method