Thermodynamic modelling of a recompression CO2 power cycle for low temperature waste heat recovery

Banik, Shubham; Ray, Satyaki; De, S. K.

doi:10.1016/j.applthermaleng.2016.06.179

Cited by 34 publications

(4 citation statements)

References 25 publications

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“…Exergy efficiency has been used to evaluate and optimize systems in many works. 12,[23][24][25][26] Guo et al 27 proposed a novel quantity-entransy, to describe the heat transfer ability. The total entransy is always dissipated in isolated systems, and the entransy dissipation could measure the irreversibility in heat transfer processes.…”

Section: Evaluation Of Heat Transfer and Whr Systemmentioning

confidence: 99%

Analysis of two‐stage waste heat recovery based on natural gas‐fired boiler

et al. 2019

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Summary Waste heat recovery (WHR) is crucial to the efficiency improvement of natural gas‐fired boiler systems. Two‐stage WHR systems based on the natural gas‐fired boiler were analyzed from the viewpoints of thermal efficiency and heat transfer irreversibility. An overall entransy dissipation‐based thermal resistance was derived to evaluate the irreversibility of WHR, including the entransy dissipations during condensation and in absorption heat pump (AHP). Compared with the basic WHR system, the two‐stage WHR systems have higher boiler efficiency and less irreversibility. The air‐humidified system recycles both the heat and vapor in flue gas, while the unutilized latent heat in the recovered vapor causes the boiler to be less efficient than the AHP system. Investigation on heat exchanger effectiveness of two‐stage WHR systems illustrated: in the two‐stage WHR system with air humidification, the increasing effectiveness of both heat exchangers could effectively increase boiler efficiency and reduce heat transfer irreversibility. In the two‐stage WHR system with AHP, boiler efficiency has a local optimum when the dew point occurs near the outlet of the first heat exchanger; increasing the second heat exchanger effectiveness is more efficient in improving boiler efficiency. The present work may provide available references and guidance for the design and optimization of the two‐stage WHR systems.

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Section: Evaluation Of Heat Transfer and Whr Systemmentioning

confidence: 99%

Analysis of two‐stage waste heat recovery based on natural gas‐fired boiler

et al. 2019

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“…The improved CO2 based power cycle gives better performance compared to the basic cycle and the ORC. Thermodynamic modelling of a recompression CO2 power cycle for WHR was performed by Banik et al [24] for potential higher cycle efficiency. The thermodynamic performance of basic recuperated sCO2 cycle is limited by heat capacity mismatch in the recuperator.…”

Section: Introductionmentioning

confidence: 99%

Dynamic modelling and control of supercritical CO2 power cycle using waste heat from industrial processes

Olumayegun

Wang

2019

Fuel

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Large amount of waste heat is available for recovery in industrial processes worldwide. However, significant proportion (up to 50%) of this thermal energy is released directly to the environment. Application of waste heat to power (WHP) technologies can increase the energy efficiency and cut CO2 emissions from these facilities. Steam Rankine cycle (SRC) and organic Rankine cycle (ORC) are commonly deployed for this purpose. The main drawback of SRC and ORC is the high irreversibility in the heat exchangers. In addition, ORC has limited temperature range and low efficiency while SRC has a large footprint. Supercritical CO2 (sCO2) power cycle is considered an attractive option, which provides better matching of waste heat temperature in the main heater (i.e. low irreversibility). It offers compact design, improved performance and it is applicable to a wide range of waste heat source temperature. The conditions of industrial waste heat sources are highly variable due to continuous fluctuations in the operation of the process. This is likely to significantly affect the dynamic performance and operation of the sCO2 power cycle. In this work, dynamic model in Matlab/Simulink was developed to assess the dynamic performance and control of the sCO2 power cycle for waste heat recovery from cement industry. The case of waste heat at 380 0 C utilized to deliver 5 MWe of power was considered. Steady state simulation was performed to determine the design point values. Open loop simulation was performed to show the inherent dynamic response to step change in the temperature of the waste heat. The dynamic performance and control of the system under varying exhaust gas flow rate between 100% and 50% of the design value were studied. Similar study was done for varying exhaust gas temperature between 380 0 C and 300 0 C. The results showed that the thermal efficiency of proposed single recuperator recompression sCO2 is about 33%. Stable operation of the system can achieved by using cooling water control and throttle valve to maintain constant precooler outlet condition. Dynamic simulation result showed that it is best to allow the turbine inlet temperature to vary according to the fluctuation in the waste heat source. These findings indicated that dynamic modelling and simulation of WHP system could contribute to understanding of the behaviour and control system development under fluctuating waste heat source conditions.

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“…Recently, Wang et al [34] reviewed and compared the main s-CO2 cycle configurations integrated with molten salt solar power towers having both the main heater and a reheater. S-CO2 cycles and the various configurations have also been investigated as bottoming cycles for fuel cell [20] and gas turbine system [15] as well as an alternative power conversion system for other waste heat recovery processes [35,36] and biomass plants [7]. Bae et al [20] investigated s-CO2 cycle configurations comprising an s-CO2 Brayton-steam Rankine cycle cascade, a recompression cycle and two simple recuperated cycle (a supercritical and a transcritical cycle) as bottoming cycles for molten carbonate fuel cell.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic performance evaluation of supercritical CO2 closed Brayton cycles for coal-fired power generation with solvent-based CO2 capture

Olumayegun

Wang

Oko

2019

Energy

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Power generation from coal-fired power plants represents a major source of CO2 emission into the atmosphere. Efficiency improvement and integration of carbon capture and storage (CCS) facilities have been recommended for reducing the amount of CO2 emissions. The focus of this work was to evaluate the thermodynamic performance of s-CO2 Brayton cycles coupled to coal-fired furnace and integrated with 90% post-combustion CO2 capture. The modification of the s-CO2 power plant for effective utilisation of the sensible heat in the flue gas was examined. Three bottoming s-CO2 cycle layouts were investigated, which included a newly proposed single recuperator recompression cycle. The performances of the coal-fired s-CO2 power plant with and without carbon capture were compared. Results for a 290 bar and 593 0 C power cycle without CO2 capture showed that the configuration with single recuperator recompression cycle as bottoming cycle has the highest plant net efficiency of 42.96% (Higher Heating Value). Without CO2 capture, the efficiencies of the coal-fired s-CO2 cycle plants were about 3.34-3.86% higher than the steam plant and about 0.68-1.31% higher with CO2 capture. The findings so far underscored the promising potential of cascaded s-CO2 power cycles for coal-fired power plant application.

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Thermodynamic modelling of a recompression CO2 power cycle for low temperature waste heat recovery

Cited by 34 publications

References 25 publications

Analysis of two‐stage waste heat recovery based on natural gas‐fired boiler

Analysis of two‐stage waste heat recovery based on natural gas‐fired boiler

Dynamic modelling and control of supercritical CO2 power cycle using waste heat from industrial processes

Thermodynamic performance evaluation of supercritical CO2 closed Brayton cycles for coal-fired power generation with solvent-based CO2 capture

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