Abstract
Developed power variation of turbogenerator (TG) steam turbine, which operates at the conventional LNG carrier, allows insight into the change in turbine exergy efficiency and exergy destruction during the increase in turbine power. Measurements of required operating parameters were performed in eight different TG steam turbine operating points during exploitation. Turbine exergy efficiency increases from turbine power of 500 kW up to 2700 kW, and maximum exergy efficiency was obtained at 70.13% of maximum turbine developed power (at 2700 kW) in each operating point. From turbine developed power of 2700 kW until the maximum power of 3850 kW, exergy efficiency decreases. Obtained change in TG turbine exergy efficiency is caused by an uneven intensity of increase in turbine developed power and steam mass flow through the turbine. TG steam turbine exergy destruction change is directly proportional to turbine load and to steam mass flow through the turbine—higher steam mass flow results in a higher turbine load which leads to the higher exergy destruction and vice versa. The higher share of turbine developed power and the lower share of turbine exergy destruction in the TG turbine exergy power inlet lead to higher turbine exergy efficiencies. At each observed operating point, turbine exergy efficiency in exploitation is lower when compared to the maximum obtained one for 8.39% to 12.03%.
Highlights
Marine propulsion systems nowadays are usually based on diesel engines [1]
Steam propulsion system on the Liquefied natural gas TG (LNG) carrier always consists of two steam generators [8] due to safety and reliable operation. ose steam generators have burners which can operate with two fuels simultaneously—with evaporated natural gas from cargo tanks and with heavy fuel oil, so its operation dynamics differ greatly when compared to industrial scale furnaces [9]
Obtained areas of turbine maximum exergy efficiency and minimum exergy destruction were compared with the real LNG carrier exploitation. e main conclusion of TG steam turbine exergy analysis is that, in exploitation, turbine should be more loaded to obtain higher exergy efficiency in each operating point, but it would not be advisable that turbine operates at maximum load
Summary
Marine propulsion systems nowadays are usually based on diesel engines [1]. Because of their wide usage, a lot of simulation and optimization numerical models were developed [2, 3] in order to investigate their operating parameters. E structure of marine steam propulsion system does not differ greatly in comparison with land-based steam power systems [7], but some of its components and the principle of operation can significantly vary. Ose steam generators have burners which can operate with two fuels simultaneously—with evaporated natural gas from cargo tanks and with heavy fuel oil, so its operation dynamics differ greatly when compared to industrial scale furnaces [9]. Each steam generator has an air heater where the air is heated with a steam because flue gasses from marine steam generators do not have high enough temperature for additional heating purposes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
