DESIGNING FLEXIBILITY INTO A HYBRID SOLAR THERMAL POWER PLANT BY REAL-TIME, ADAPTIVE HEAT INTEGRATION

摘要

This study presents the concept of flexible heat integration (FHI) applied to a concentrated solar power (CSP)-natural gas hybrid power plant and employing non-1inear real-time optimization (RTO) to leverage the FHI concept. In a conventional CSP plant driven by a trough collector, solar energy is dispatched in series to heat sinks at decreasing temperature. FHI dispatches solar energy to the heat sinks within the power plant based upon ambient conditions, rather than always in series. During times of low solar activity, solar energy bypasses the steam generator and is dispatched directly to the preheater. A nonlinear optimization capitalizes on this flexible operation and establishes different collection temperature set points based upon the availability of solar power. This mechanism enables the plant to mitigate radiative heat losses of low-grade solar power, as observed when heat is only utilized at high temperature and in series. Applying FHI and RTO increases the solar fraction by 18.2% and the solar-to-electric efficiency by 15.5%. These results indicate the potential of significant improvement of solar power production in a hybrid plant by leveraging the benefits of RTO and FHI. Compared to a solar only power plant, the combination of the hybrid design, EHI, and RTO nearly doubles the amount of solar power produced.