Thermodynamic Analysis of a Condensate Heating System from a Marine Steam Propulsion Plant with Steam Reheating

Mrzljak, Vedran; Lorencin, Ivan; Anđelić, Nikola; Car, Zlatan

doi:10.1007/s11804-021-00191-5

Cited by 5 publications

(8 citation statements)

References 61 publications

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“…In this research, that components are SA and MC. The confirmation of this statement can be found in [64] where is confirmed that in the marine condensate/ feedwater heating system, heater which is the closest to the main condenser (and which operating parameters are the closest to the ambient state) has the lowest exergy efficiency and is highly influenced by the change in the ambient parameters.…”

Section: Figure 5 -Exergy Destruction Of All Components From the Obse...mentioning

confidence: 66%

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Exergy Analysis of Supercritical CO2 System for Marine Diesel Engine Waste Heat Recovery Application

Mrzljak,

Jelić,

Poljak

et al. 2023

JMTS

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In this research is performed an exergy analysis of supercritical CO2 system which uses various waste heat flows from marine diesel engine to produce additional mechanical power. The performed exergy analysis contains whole system as well as each system component individually. The observed system produces useful mechanical power equal to 2299.47 kW which is transferred to the main propulsion propeller shaft. Additionally produced mechanical power by using waste heat only will reduce marine diesel engine fuel consumption and exhaust gas emissions. Main cooler has the highest exergy destruction of all system components and simultaneously the lowest exergy efficiency in the observed system, equal to 32.10% only. One of the possibilities how main cooler exergy efficiency can be increased is by decreasing water mass flow rate through the main cooler and simultaneously by increasing water temperature at the main cooler outlet. Observed system has five heat exchangers which are involved in the CO2 heating process, and it is interesting that the last CO2 heater (exhaust gas waste heat exchanger) increases the CO2 temperature more than all previous four heat exchangers. Whole analyzed waste heat recovery supercritical CO2 system has exergy destruction equal to 2161.68 kW and exergy efficiency of 51.54%. In comparison to a similar CO2 system which uses waste heat from marine gas turbine, system analyzed in this paper has approximately 12% lower exergy efficiency due to much lower waste heat temperature levels (from marine diesel engine) in comparison to temperature levels which occur at the marine gas turbine exhaust.

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Section: Figure 5 -Exergy Destruction Of All Components From the Obse...mentioning

confidence: 66%

“…4. For the specific exergies calculation must be defined the base ambient state [64]. The base ambient state can be selected arbitrarily and is related to the pressure and temperature of the ambient in which observed component or a system operates.…”

Section: Operating Parameters Required For the Waste Heat Recovery Su...mentioning

confidence: 99%

Exergy Analysis of Supercritical CO2 System for Marine Diesel Engine Waste Heat Recovery Application

Mrzljak,

Jelić,

Poljak

et al. 2023

JMTS

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“…Exergy analysis shows different kind of losses in comparison to the energy analysis, therefore the conclusions obtained in energy analysis can strongly differ in regards to exergy analysis conclusions. Moreover, energy analysis of some systems or processes can be practically unusable due to its high dependence on the measurement Pomorski zbornik 62 (2022), 9-30 Thermodynamic Analysis... Vedran Mrzljak, Tomislav Senčić, Igor Poljak, Vedran Medica-Viola equipment accuracy and precision -one example can be found in [58] for a condensate/ feedwater marine heating system.…”

Section: Resultsmentioning

confidence: 99%

Thermodynamic Analysis of Steam Cooling Process in Marine Power Plant by Using Desuperheater

Mrzljak

Senčić

Poljak

et al. 2022

JMTS

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Thermodynamic (energy and exergy) analysis of steam cooling process in the marine steam propulsion plant is presented in this research. Steam cooling is performed by using Desuperheater which inject water in the superheated steam to obtain wet steam. Wet steam is used in auxiliary heaters for various heating purposes inside the marine steam propulsion system. Auxiliary heaters require wet steam due to safety reasons and for easier steam condensation after heat transfer. Analysis of steam cooling process is performed for a variety of steam system loads. Mass flow rates of cooling water and superheated steam in a properly balanced cooling process should have the same trends at different system loads -deviations from this conclusion is expected only for a notable change in any fluid temperature. Reduction in steam temperature is dependable on the superheated steam temperature (at Desuperheater inlet) because the temperature of wet steam (at Desuperheater outlet) is intended to be almost constant at all steam system loads. Energy losses of steam cooling process for all observed system loads are low and in range between 10-30 kW, while exergy losses are lower in comparison to energy losses (between 5-15 kW) for all loads except three the highest ones. At the highest system loads exergy losses strongly increase and are higher than 20 kW (up to 40 kW). The energy efficiency of a steam cooling process is very high (around 99% or higher), while exergy efficiency is slightly lower than energy efficiency (around 98% or higher) for all loads except the highest ones. At the highest steam system loads, due to a notable increase in cooling water mass flow rate and high temperature reduction, steam cooling process exergy efficiency significantly decreases, but still remains acceptably high (between 95% and 97%). Observation of both energy and exergy losses and efficiencies leads to conclusion that exergy analysis consider notable increase in mass flow rate of cooling water which thermodynamic properties (especially specific exergies) strongly differs in comparison to steam. Such element cannot be seen in the energy analysis of the same system.

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“…The same conclusion can be found in the literature [77] for a steam turbines which dominantly operate by using superheated steam. The exergy efficiency of the analyzed steam turbine is low sensitive by the ambient temperature change what significantly differs in comparison to some other components (for example, low pressure condensate heaters) which also uses wet steam for its operation [98].…”

Section: Exergy Analysis During the Ambient Temperature Changementioning

confidence: 96%

“…Also, it was interesting to analyze did a new operating pa-rameters obtained by each algorithm notably influenced steam turbine sensitivity on the ambient temperature change, especially by taking into consideration fact that the dominant operation of any steam turbine from any nuclear power plant is performed with wet (not superheated) steam. As presented in [98], components which operates by using wet steam (in this example, heat exchangers) can be notably influenced by the ambient temperature change. So, the analysis presented in this paper represents a continuation of a previous research with an aim to get a deeper insight into the steam turbine operation after optimization of the whole power plant.…”

Section: Operating Parameters Required For the Observed Steam Turbine Exergy Analysismentioning

confidence: 99%

The influence of various optimization algorithms on nuclear power plant steam turbine exergy efficiency and destruction

et al. 2021

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This paper presents an exergy analysis of the whole turbine, turbine cylinders and cylinder parts in four different operating regimes. Analyzed turbine operates in nuclear power plant while three of four operating regimes are obtained by using optimization algorithms – SA (Simplex Algorithm), GA (Genetic Algorithm) and IGSA (Improved Genetic-Simplex Algorithm). IGSA operating regime gives the highest developed mechanical power of the whole turbine equal to 1022.48 MW, followed by GA (1020.06 MW) and SA (1017.16 MW), while in Original operating regime whole turbine develop mechanical power equal to 996.29 MW. In addition, IGSA causes the highest increase in developed mechanical power of almost all cylinders and cylinder parts in comparison to the Original operating regime. All observed optimization algorithms increases the exergy destruction of the whole turbine in comparison to Original operating regime - the lowest increase causes IGSA, followed by GA and finally SA. The highest exergy efficiency of the whole turbine, equal to 85.92% is obtained by IGSA, followed by GA (85.89%) and SA (85.82%), while the lowest exergy efficiency is obtained in Original operating regime (85.70%). Analyzed turbine, which operates by using wet steam is low influenced by the ambient temperature change. IGSA, which shows dominant performance in exergy analysis parameters of the analyzed turbine, in certain situations is overpowered by GA. Therefore, in optimization of steam turbine performance, IGSA and GA can be recommended.

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Thermodynamic Analysis of a Condensate Heating System from a Marine Steam Propulsion Plant with Steam Reheating

Cited by 5 publications

References 61 publications

Exergy Analysis of Supercritical CO2 System for Marine Diesel Engine Waste Heat Recovery Application

Exergy Analysis of Supercritical CO2 System for Marine Diesel Engine Waste Heat Recovery Application

Thermodynamic Analysis of Steam Cooling Process in Marine Power Plant by Using Desuperheater

The influence of various optimization algorithms on nuclear power plant steam turbine exergy efficiency and destruction

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