Waste heat recovery of a combined solid oxide fuel cell - gas turbine system for multi-generation purposes

Author(s):  
Yan Cao ◽  
Mohammad Zoghi ◽  
Hamed Habibi ◽  
Amir Raise
Author(s):  
Christopher J. Maxey ◽  
Gregory S. Jackson ◽  
Seyed-Abdolreza Seyed Reihani ◽  
Steven C. Decaluwe ◽  
Siddharth Patel ◽  
...  

To facilitate high-power density operation of a meso-scale solid oxide fuel cell (SOFC) system, fuel processing and anode exhaust catalytic combustor with waste heat recovery are critical components. An integrated modeling study of a catalytic combustor with a solid oxide fuel cell and a catalytic partial oxidation (CPOx) reactor indicates critical aspects of the butane-fueled system design in order to ensure stable operation of the SOFC as well as the combustor and CPOx reactor. The modeled system consists of: 1) a Rh-coated ceramic foam catalytic partial oxidation reactor, 2) a SOFC with a Ni/YSZ structural anode, a dense YSZ electrolyte, and a LSM/YSZ cathode layer, and 3) a Pt-coated anode exhaust combustor with waste heat recovery. Model results for a system designed to produce < 30 W electric power from n-butane show how the design of the inlet-air cooled catalytic combustor can maximize combustion efficiency of the anode exhaust and heat recovery to the system inlet air flow. The model also shows the need to minimize heat loss in the air flow passages in order to maintain stable SOFC operation at 700 °C or higher. There is a strong sensitivity of the system operation to the SOFC operating voltage as well as the overall air to fuel ratio, and these sensitivities place important bounds on the range of operating conditions.


2012 ◽  
Vol 622-623 ◽  
pp. 1162-1167
Author(s):  
Han Fei Tuo

In this study, energetic based fluid selection for a solid oxide fuel cell-organic rankine combined power system is investigated. 9 dry organic fluids with varied critical temperatures are chosen and their corresponding ORC cycle performances are evaluated at different turbine inlet temperatures and exhaust gas temperature (waste heat source) from the upper cycle. It is found that actual ORC cycle efficiency for each fluid strongly depends on the waste heat recovery performance of the heat recovery vapor generator. Exhaust gas temperature determines the optimal fluid which yields the highest efficiency.


Author(s):  
Valentina Amati ◽  
Enrico Sciubba ◽  
Claudia Toro

The paper presents the exergy analysis of a natural gas fuelled energy conversion process consisting of a hybrid solid oxide fuel cell coupled with a gas turbine. The fuel is partly processed in a reformer and then undergoes complete reforming in an internal reforming planar SOFC stack (IRSOFC). The syngas fuels in turn a standard gas turbine cycle that drives the fuel compressor and generates excess shaft power. Extensive heat recovery is enforced both in the Gas Turbine and between the topping SOFC and the bottoming GT. Two different configurations have been simulated and compared on an exergy basis: in the first one, the steam needed to support the external and the internal reforming reactions is completely supplied by an external Heat Recovery Steam Generator (HRSG), while in the second one that steam is mainly obtained by recirculating part of the steam-rich anode outlet stream. The thermodynamic model of the fuel cell system has been developed and implemented into the library of a modular object-oriented Process Simulator, Camel-Pro®; then, by means of this simulator, the exergetic performance of the two alternative configurations has been analyzed. A detailed analysis of the exergy destruction at component level is presented, to better assess the distribution of irreversibilities along the process and to gain useful design insight.


Author(s):  
Souman Rudra ◽  
A. S. M. Sayem ◽  
S. K. Biswas ◽  
Soonil Lee ◽  
Hyung Taek Kim

The fuel cell model developed to this research is based on a solid oxide fuel cell (SOFC) integrated with a heat recovery steam generator (HRSG), a gas turbine (GT) and a steam turbine (ST). Three possible technological approaches are compared to suggest the desirable combine cycle. First approach indicates the generation of the required steam in the coupled SOFC and gas turbine cycle. Then the exhaust gas from gas turbine involves driving the HRSG. And the last one involves of using exhaust gases in the HRSG which drives the steam turbine by producing steam for additional power works. To achieve the more efficient conversation of the thermal energy to power output, the component design mainly HRSG and steam turbine have to be made in a great concern. And HRSG is considered as a triple pressure for the taken model. This article is also delineated the analysis of coal fed instead of normal methane gas fed, for the reforming power generation based on thermodynamic processes including CO2 Capture. External reforming in SOFC-HRSG plants fueled by high quality coal enhances efficiency due to improved exhaust heat recovery and higher voltage produced by higher hydrogen partial pressure in the anode inlet. For improving the whole cycle efficiency, power output generation from both SOFC and conventional system (steam turbine and gas turbine) are described as combine system. This model is simulated by the ASPEN plus software which is able to provide thermodynamic and parametric analysis to evaluate the effects of various parameters like air flow rate, temperature, pressure and fuel flow rate on the system performance. Some MATLAB simulations are also added to provide strong opinion for this model through this paper.


Author(s):  
Giulio Vialetto ◽  
Marco Noro ◽  
Masoud Rokni

In this paper, a new heat recovery for a microcogeneration system based on solid oxide fuel cell and air source heat pump (HP) is presented with the main goal of improving efficiency on energy conversion for a residential building. The novelty of the research work is that exhaust gases after the fuel cell are first used to heat water for heating/domestic water and then mixed with the external air to feed the evaporator of the HP with the aim of increasing energy efficiency of the latter. This system configuration decreases the possibility of freezing of the evaporator as well, which is one of the drawbacks for air source HP in Nordic climates. A parametric analysis of the system is developed by performing simulations varying the external air temperature, air humidity, and fuel cell nominal power. Coefficient of performance (COP) can increase more than 100% when fuel cell electric power is close to its nominal (50 kW), and/or inlet air has a high relative humidity (RH) (close to 100%). Instead, the effect of mixing the exhausted gases with air may be negative (up to −25%) when fuel cell electric power is 20 kW and inlet air has 25% RH. Thermodynamic analysis is carried out to prove energy advantage of such a solution with respect to a traditional one, resulting to be between 39% and 44% in terms of primary energy. The results show that the performance of the air source HP increases considerably during cold season for climates with high RH and for users with high electric power demand.


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