A Solar-Hybrid Power Plant Integrated With Ethanol Chemical-Looping Combustion

Author(s):  
Hui Hong ◽  
Ying Pan ◽  
Xiaosong Zhang ◽  
Tao Han ◽  
Shuo Peng ◽  
...  

In this paper, a new solar hybrid gas turbine cycle integrating ethanol-fueled chemical-looping combustion (CLC) has been proposed, and the system was investigated with the aid of the Energy-Utilization Diagram (EUD). Chemical-looping combustion consists of two successive reactions: first, ethanol fuel is oxidized by metal oxide (NiO) as an oxygen carrier (reduction of metal oxide); secondly, the reduced metal (Ni) is successively oxidized by combustion air (the oxidation of metal). The reduction of NiO with ethanol requires a relative low-grade thermal energy at 150–200°C. Then concentrated solar thermal energy at approximately 200–300°C can be utilized to provide the process heat for this reaction. The integration of solar thermal energy and CLC could make the exergy efficiency and the net solar-to-electric efficiency of the system more than 54% and 28% at a turbine inlet temperature (TIT) of 1288°C, respectively. At the same time, the variation in the overall thermal efficiency (η) of the system with varying key parameters was analyzed, such as Turbine Inlet Temperature, pressure ratio (π) and the temperature of reduction reactor. Additionally, preliminary experiments on ethanol-fueled chemical-looping combustion are carried out to verify the feasibility of the key process. The promising results obtained here indicate that this novel gas turbine cycle with ethanol-fueled chemical-looping combustion could provide a promising approach of both efficient use of alternative fuel and low-temperature solar thermal and offer a technical probability of combining the chemical-looping combustion with inherent CO2 capture for the alternative fuel.

2006 ◽  
Vol 128 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Baiqian Liu

In this paper we propose a novel CO2-recovering hybrid solar-fossil combined cycle with the integration of methane-fueled chemical-looping combustion, and investigate the system with the aid of the Energy-Utilization Diagram (EUD). Chemical-looping combustion (CLC) consists of two successive reactions: first, methane fuel is oxidized by metal oxide(NiO)as an oxygen carrier (reduction of metal oxide); and second, the reduced metal (Ni) is successively oxidized by combustion air (the oxidation of metal). The oxidation of methane with NiO requires a relative low-grade thermal energy at 300°C-500°C. Then concentrated solar thermal energy at approximately 450°C-550°C can be utilized to provide the process heat for this reaction. By coupling solar thermal energy with methane-fueled chemical-looping combustion, the energy level of solar thermal energy at around 450°C-550°C can be upgraded to the chemical energy of solid fuel Ni for better utilization of solar energy to generate electricity. The synergistic integration of solar thermal energy and chemical-looping combustion could make the exergy efficiency and the net solar-to-electric efficiency of the solar hybrid system more than 60% and 30%, respectively, at a turbine inlet temperature (TIT) of 1200°C. At the same time, this new system has an extremely important advantage of directly suppressing the environmental impact due to lack of energy penalty for CO2 recovery. Approximately 9–15 percentage points higher efficiency can be achieved compared to the conventional natural gas-fired combined cycle with CO2 separation. The results obtained here are promising and indicate that this novel solar hybrid combined cycle offers the new possibility of CO2 mitigation using both green energy and fossil fuels. These results also provide a new approach for highly efficient use of solar thermal energy to generate electricity.


Author(s):  
Hui Hong ◽  
Tao Han ◽  
Hongguang Jin

A novel solar-hybrid gas turbine combined cycle was proposed. The cycle integrates methanol-fueled chemical-looping combustion and solar thermal energy at around 200°C, and it was investigated with the aid of the Energy-Utilization Diagram (EUD). Solar thermal energy, at approximately 150°C–300°C, is utilized to drive the reduction of Fe2O3 with methanol in the reduction reactor, and is converted into chemical energy associated with the solid fuel FeO. Then it is released as high-temperature thermal energy during the oxidation of FeO in the oxidation reactor to generate electricity through the combined cycle. As a result, the exergy efficiency of the proposed solar thermal cycle may reach 58.4% at a turbine inlet temperature (TIT) of 1400°C, and the net solar-to-electric efficiency would be expected to be more than 30%. The promising results obtained here indicate that this solar-hybrid combined cycle not only offers a new approach for highly efficient use of middle-and-low temperature solar thermal energy to generate electricity, but also provides the possibility of simultaneously utilizing renewable energy and alternative fuel for CO2 capture with low energy penalty.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Hui Hong ◽  
Tao Han ◽  
Hongguang Jin

A novel solar-hybrid gas turbine combined cycle was proposed. The cycle integrates methanol-fueled chemical-looping combustion and solar thermal energy at around 200°C, and it was investigated with the aid of the energy-utilization diagram (EUD). Solar thermal energy, at approximately 150°C–300°C, is utilized to drive the reduction in Fe2O3 with methanol in the reduction reactor, and is converted into chemical energy associated with the solid fuel FeO. Then it is released as high-temperature thermal energy during the oxidation of FeO in the oxidation reactor to generate electricity through the combined cycle. As a result, the exergy efficiency of the proposed solar thermal cycle may reach 58.4% at a turbine inlet temperature of 1400°C, and the net solar-to-electric efficiency would be expected to be 22.3%. The promising results obtained here indicate that this solar-hybrid combined cycle not only offers a new approach for highly efficient use of middle-and-low temperature solar thermal energy to generate electricity, but also provides the possibility of simultaneously utilizing renewable energy and alternative fuel for CO2 capture with low energy penalty.


Author(s):  
Hongguang Jin ◽  
Xiaosong Zhang ◽  
Hui Hong ◽  
Wei Han

In this paper, a novel gas turbine cycle integrating methanol decomposition and the chemical-looping combustion (CLC) is proposed. Two types of methanol-fueled power plants, including the new gas turbine cycle with CLC combustion and a chemically intercooled gas turbine cycle, have been investigated with the aid of the T-Q diagram. In the proposed system, methanol fuel is decomposed into syngas mainly containing H2 and CO by recovering low-temperature thermal energy from an intercooler of the air compressor. After the decomposition of methanol, the resulting product of syngas is divided into two parts: the part reacting with Fe2O3 is sent into the CLC subsystem, and the other part is introduced into a supplement combustor to enhance the inlet temperatures of the gas turbine to 1100–1500°C. As a result, the new methanol-fueled gas turbine cycle with CLC had a breakthrough in thermodynamic and environmental performance. The thermal efficiency of the new system can achieve 60.6% with 70% of CO2 recovery at a gas turbine inlet temperature of 1300°C. It would be expected to be at least about 10.7 percentage points higher than that of the chemically intercooled gas turbine cycle with the same recovery of CO2 and is environmentally superior due to the recovery of CO2. The promising results obtained here indicated that this novel gas turbine cycle with methanol-fueled chemical-looping combustion could provide a promising approach of both effective use of alternative fuel and recovering low-temperature waste heat and offer a technical probability of blending a combination of the chemical-looping combustion and the advanced gas turbine for carbon capture and storage.


Author(s):  
Fengjuan He ◽  
Tao Han ◽  
Hui Hong ◽  
Hongguang Jin

In this paper, we propose a new solar-hybrid trigeneration system with dimethyl ether (DME)-fueled chemical-looping combustion and solar thermal energy at approximately 550°C. The system is investigated using the energy-utilization diagram (EUD). In this system, the concentrated solar thermal energy is utilized to drive the endothermic reduction of CoO with DME in the fuel reactor, producing solid fuel of Co and gaseous CO2 as well as water vapor. Subsequently, the reduced metal oxide Co is transported into the air reactor to be oxidized for regeneration at 1,000 °C. The high-temperature flue gas from the air reactor is introduced into the gas turbine to generate power, and then it enters an absorption chiller with coefficient of performance (COP) of 1.2 to produce cooling. Finally, the high-temperature flue gas is used for the production of domestic hot water at 70 °C through a heat exchanger. The gaseous product from the fuel reactor consists only of CO2 and water vapor, so CO2 can be easily separated through the condensing method with super low extra energy penalty. As a result, the thermal efficiency of the new system is expected to be 96.7%, and the global exergy efficiency can reach 35%. Two important indicators of fuel energy saving ratio (FESR) and solar area saving ratio (SASR) are used to evaluate the performance of the system. FESR can reach 40.6% at a turbine inlet temperature of 1,000 °C, whereas SASR can reach 68.4%. A preliminary experiment is also conducted. The promising results obtained in this study provide a new approach for highly efficient use of solar thermal energy approximately 550°C and offer a possibility of simultaneously utilizing solar energy and alternative fuel for CO2 capture with low energy penalty.


Author(s):  
Yasuyoshi Kato

Three systems have been proposed for advanced high temperature gas-cooled reactors (HTGRs): a supercritical carbon dioxide (S-CO2) gas turbine power conversion system; a new MicroChannel Heat Exchanger (MCHE); and a once-through-then-out (OTTO) refueling scheme with burnable poison (BP) loading. An S-CO2 gas turbine cycle attains higher cycle efficiency than a He gas turbine cycle due to reduced compression work around the critical point of CO2. Considering temperature lowering at the turbine inlet by 30°C through the intermediate heat exchange, the S-CO2 indirect cycle achieves efficiency of 53.8% at turbine inlet temperature of 820°C and turbine inlet pressure of 20 MPa. This cycle efficiency value is higher by 4.5% than that (49.3%) of a He direct cycle at turbine inlet temperature of 850°C and 7 MPa. A new MCHE has been proposed as intermediate heat exchangers between the primary cooling He loop and the secondary S-CO2 gas turbine power conversion system; and recuperators of the S-CO2 gas turbine power conversion system. This MCHE has discontinuous “S”-shape fins providing flow channels with near sine curves. Its pressure drop is one-sixth reference to the conventional MCHE with zigzag flow channel configuration while the same high heat transfer performance inherits. The pressure drop reduction is ascribed to suppression of recirculation flows and eddies that appears around bend corners of zigzag flow channels in the conventional MCHE. An optimal BP loading in an OTTO refueling scheme eliminates the drawback of its excessively high axial power peaking factor, reducing the power peaking factor from 4.44 to about 1.7; and inheriting advantages over the multi-pass scheme because of the lack of fuel handling and integrity checking systems; and reloading. Because of the power peaking factor reduction, the maximum fuel temperatures are lower than the maximum permissible values of 1250°C for normal operation and 1600°C during a depressurization accident.


Energy ◽  
2019 ◽  
Vol 170 ◽  
pp. 93-101 ◽  
Author(s):  
Mahyar Silakhori ◽  
Mehdi Jafarian ◽  
Maziar Arjomandi ◽  
Graham J. Nathan

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