A Novel Solar-Hybrid Gas Turbine Combined Cycle With Inherent CO2 Separation Using Chemical-Looping Combustion by Solar Heat Source

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):  
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.


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):  
Hongguang Jin ◽  
Hui Hong ◽  
Jun Ji ◽  
Zhifeng Wang ◽  
Ruixian Cai

In this paper, we have proposed a novel solar–driven combined cycle with solar upgrading of methanol in middle temperature solar collectors, and investigated the effects of integration of solar thermal energy and methanol decomposition on the performance of the proposed cycle. The process of solar upgrading methanol is a catalytically endothermic decomposition reaction and proceeds in a range of 130–250° C. As a result, the proposed cycle has a breakthrough performance, with net solar–to–electric efficiency of 32.93% at the collector temperature of 220° C, and the turbine inlet temperature of 1062° C, superior to that of the present advanced cycle (REFOS of 20%). The exergy loss in indirect combustion of methanol proposed here is 7.5 percent points lower than that of the direct combustion. The optimum pressure ratio for thermal efficiency is approximately equal to 14. A key point emphasized here is that the proposed new cycle can utilize middle–temperature solar collector with lower cost. The promising results obtained here indicated that this novel solar–driven combined cycle could make a breakthrough in field of solar thermal power generation through integration of solar thermal energy and effective use of synthetic clean fuel.


2020 ◽  
Vol 12 (19) ◽  
pp. 8178
Author(s):  
Fahid Riaz ◽  
Kah Hoe Tan ◽  
Muhammad Farooq ◽  
Muhammad Imran ◽  
Poh Seng Lee

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3443
Author(s):  
Mohammed N. Khan ◽  
Schalk Cloete ◽  
Shahriar Amini

Chemical looping combustion (CLC) technology generates power while capturing CO2 inherently with no direct energy penalty. However, previous studies have shown significant energy penalties due to low turbine inlet temperature (TIT) relative to a standard natural gas combined cycle plant. The low TIT is limited by the oxygen carrier material used in the CLC process. Therefore, in the current study, an additional combustor is included downstream of the CLC air reactor to raise the TIT. The efficient production of clean hydrogen for firing the added combustor is key to the success of this strategy. Therefore, the highly efficient membrane-assisted chemical looping reforming (MA-CLR) technology was selected. Five different integrations between CLC and MA-CLR were investigated, capitalizing on the steam in the CLC fuel reactor outlet stream to achieve highly efficient reforming in MA-CLR. This integration reduced the energy penalty as low as 3.6%-points for power production only (case 2) and 1.9%-points for power and hydrogen co-production (case 4)—a large improvement over the 8%-point energy penalty typically imposed by post-combustion CO2 capture or CLC without added firing.


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