The paper presents thermodynamic (energy and exergy) analysis of low-power steam turbine with one extraction for marine applications. Analyzed steam turbine is divided in two parts-High Pressure (HP) part before steam extraction and Low Pressure (LP) part after steam extraction. Analysis shows that HP turbine part produces the majority of cumulative turbine power and consequentially has higher mechanical, energy and exergy losses when compared to LP turbine part. Regardless of heavier operating conditions, LP turbine part has higher effi ciencies and lower specifi c losses (in both energy and exergy analysis) when compared to HP turbine part. Whole analyzed turbine has energy and exergy effi ciencies equal to 62.84% and 65.58%, while energy and exergy turbine losses are 696.74 kW and 618.50 kW. Cumulative produced power at the turbine shaft outlet is equal to 1178.40 kW. Steam extraction which divides analyzed turbine on HP and LP part can deliver a notable amount of heat to any marine heat consumer, what represents a signifi cant advantage of observed turbine in comparison with similar low-power marine steam turbines which usually does not have steam extractions. Sažetak U radu je prikazana termodinamička (energijska i eksergijska) analiza parne turbine male snage s jednim oduzimanjem pare za primjenu u pomorstvu. Analizirana parna turbina podijeljena je u dva dijela-visokotlačni dio (HP) prije oduzimanja pare i niskotlačni dio (LP) nakon oduzimanja pare. Analiza pokazuje da visokotlačni dio proizvodi većinu snage turbine i posljedično ima veće mehaničke, energijske i eksergijske gubitke u usporedbi s niskotlačnim dijelom turbine. Bez obzira na teže radne uvjete, niskotlačni dio turbine ima veću učinkovitost i manje specifi čne gubitke (u energijskoj i eksergijskoj analizi) u usporedbi s visokotlačnim dijelom turbine. Cijela analizirana turbina ima energijsku i eksergijsku učinkovitost jednaku 62.84 % i 65.58 %, dok su gubici energije i eksergije turbine 696.74 kW i 618.50 kW. Kumulativna proizvedena snaga na izlazu turbinskog vratila jednaka je 1178.40 kW. Oduzimanjem pare kojim se analizirana turbina dijeli na visokotlačni i niskotlačni dio može se isporučiti značajna količina topline bilo kojem potrošaču topline u pomorskoj industriji, što predstavlja značajnu prednost promatrane turbine u usporedbi sa sličnim brodskim parnim turbinama male snage koje obično nemaju oduzimanje pare. KEY WORDS steam turbine low-power steam extraction marine applications thermodynamic analysis KLJUČNE RIJEČI parna turbina mala snaga oduzimanje pare primjena u pomorstvu termodinamička analiza

This paper presents an exergy analysis of marine waste heat recovery CO2 closed-cycle gas turbine system. Based on the operating parameters obtained in system exploitation, it is performed analysis of each system component individually, as well as analysis of the whole observed system. While observing all heat exchangers it is found that combustion gases-CO2 heat exchangers have the lowest exergy destructions and the highest exergy efficiencies (higher than 92%). The lowest exergy efficiency of all heat exchangers is detected in Cooler (51.84%). Observed system is composed of two gas turbines and two compressors. The analysis allows detection of dominant mechanical power producer and the dominant mechanical power consumer. It is also found that the turbines from the observed system have much higher exergy efficiencies in comparison to compressors (exergy efficiency of both turbines is higher than 94%, while exergy efficiency of both compressors did not exceed 87%). The whole observed waste heat recovery system has exergy destruction equal to 6270.73 kW, while the exergy efficiency of the whole system is equal to 64.12% at the selected ambient state. Useful mechanical power produced by the whole system and used for electrical generator drive equals 11204.80 kW. The obtained high exergy efficiency of the whole observed system proves its application on-board ships.

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The world is considering various solutions to reduce exhaust emissions, the use of alternative fuels and the development of more efficient marine engines. IMO the company gave guidance for future borders of individual exhaust components, taking into account a variety of applications and conditions for the operation of marine engines. Engine manufacturers have been forced to develop new technologies, to meet the existing IMO rules and regulations that are yet to come, for the emission of harmful exhaust emissions.This paper describes the experimental procedure that support the modeling of the operating parameters of marine internal combustion engines in order to diagnose the condition, optimization of engine and reduce exhaust emissions. Special attention was given to verify the adequacy of the investigation, its accuracy and relevance. It outlines experiments that support the selection procedure tests during sea trials and later in the exploitation of the ship.