title: Experimental and Numerical Investigation of the Integrated Solar Combined Cycle
Creators: name: Temraz, Ayman Lotfy Kabel
Publisher: name: UNSPECIFIED
Year: 2021

description: The Integrated Solar Combined Cycle (ISCC) features the advantages of renewable clean energy with a combined cycle. The combined cycle gas turbine (CCGT) power plants are the most recognized thermal power plants for their high efficiency, fast start-up capability and relatively low environmental impact. Moreover, their flexible unit dispatch supports the share of renewable energy, which contributes to carbon mitigation. The ISCC power plants integrate a solar field with a CCGT power plant to increases the efficiency of solar power plants while decreasing the CO2 emissions of CCGT power plants. In this thesis, experimental and numerical investigations of the ISCC were performed for an existing ISCC power plant in Kuraymat, Egypt. On one hand, energy and exergy analyses as well as dynamic process simulations were carried out. On the other hand, an experimental investigation was performed for two-phase dynamic instabilities in the Heat Recovery Steam Generator (HRSG). In the energy and exergy analysis, the overall thermal efficiency and the exergetic efficiency of each component in the ISCC power plant were calculated for different solar heat inputs and ambient temperatures. The analysis indicated that the exergetic efficiency of the plant components has its lowest value in the solar field followed by the combustion chamber. Further, the thermal efficiency and the exergetic efficiency of the ISCC power plant as a whole decrease with increasing ambient temperature and have their highest values in the combined cycle regime of operation. Owing to these results, an investigation on the sources of exergy destruction in the solar field was conducted. Then, to evaluate the limitations and capabilities of ISCC power plants and their control structures, a sophisticated dynamic process model of the plant has been developed using APROS software. The model describes the plant with a high level of detail including the solar field, the HRSG, and the control structures. The developed model was initialized using the operational design data and validated using actual measurements. Dynamic analysis of different four days was performed then the simulation results were presented and compared with actual measurements. The comparison showed that the course of the actual measurements could be predicted with high accuracy and the developed model can be considered in future planning decisions. Finally, the dynamic instabilities of the two-phase flow in the HRSG were investigated by performing experiments using demineralized water in a two-phase flow test rig with a horizontal evaporator tube. The experimental results for the main three types of dynamic instabilities (density wave oscillation, pressure drop oscillation, and thermal oscillation) were presented and compared in time and frequency domains. The comparison study showed that the density wave oscillations (DWOs) have a higher frequencies range, of about 0.04 to 0.1 Hz, compared with the pressure drop oscillations (PDOs), which have a frequencies range of about 0.012 to 0.024 Hz. The PDOs, with their lower frequencies compared to DWOs, have a more significant effect on thermal oscillations and increase the likelihood of tube burnout occurring. Since the amplitude of the surface temperature oscillations along the evaporator tube, associated with the PDOs, reached 60 °C.