The Design And Performance Analysis Of Waste Heat Recovery System For A10000TEU Container Ship

The10000TEU container ship has the characteristics of high technology, highperformance and high additional value. The main engine installed in a10000TEU containership is the low speed two-stroke large power output electronic control diesel engine, and therated power output is above5.5MW. The higher the international oil prices, the higher theproportion of oil costs in total operating costs, and to reduce the total operating costs hascaught ship owners’ attention. Meanwhile, the waste heat amount of exhaust gas is huge,exhaust gas waste heat recovery has been one of the most important ways to reduce the totaloperating costs for10000TEU container ship. However, the payback time of waste heatrecovery system is so long that no ship owners or manufacturers would take account of it.In this paper, the new generation10000TEU container ship of environmentally friendlyand energy saving is the main study object. Based on the thermodynamic parametersanalysis of main engine’s exhaust gas, three exhaust gas waste heat recovery conceptualsystems had been proposed, i.e. Rankine cycle exhaust gas waste heat recovery system,combined turbines exhaust gas waste heat recovery system and organic Rankine cycleexhaust gas waste heat recovery system. In order to analyze thermodynamic performancesand payback time of these three waste heat recovery systems, thermodynamic models ofmain components and payback time models had been given, thermodynamic performanceanalysis and payback time calculation programs had been developed, results show thatorganic Rankine cycle exhaust gas waste heat recovery system using R141b as workingfluid has the highest exergy efficiency; combined turbines exhaust gas waste heat recoverysystem has the biggest net power output; Rankine cycle exhaust gas waste heat recoverysystem has the shortest payback time under the premise that main engine’s structure doesnot change.The10000TEU container ship often operates under part load conditions due todifferent natural conditions and various navigation requirements, resulting in the change ofwaste heat recovery system’s load, so that it is necessary to make part load analysis of wasteheat recovery system. In this paper, dynamic models had been built by using transferfunction method and modular modeling method, and waste heat recovery systems’performances variation with time had been analyzed for systems whose payback time wereshorter, i.e. Rankine cycle exhaust gas waste heat recovery system, organic Rankine cycle exhaust gas waste heat recovery system using R141b as working fluid and organic Rankinecycle exhaust gas waste heat recovery system using n-pentane as working fluid. Resultsshow that these systems have self balancing abilities to disturbances, and organic Rankinecycle exhaust gas waste heat recovery system using R141b as working fluid has the shortesttransition time.Energy Efficiency Design Index and Energy Efficiency Operational Indicator are usedto calculate the energy efficiency level of ship. In this paper, Energy Efficiency DesignIndex and Energy Efficiency Operational Indicator calculation programs had beendeveloped to get Energy Efficiency Design Index and Energy Efficiency OperationalIndicator of the10000TEU container ship, the values got in this paper agreed very well withresults from the existing programs developed by other organizations. The results show thatwaste heat recovery system is one of the important ways to improve the energy efficiencylevel of ship.After design and comprehensive analysis of waste heat recovery systems, it draws aconclusion that organic Rankine cycle exhaust gas waste heat recovery system using R141bas working fluid is suitable for the10000TEU container ship; meanwhile, this paper couldgive a guide to the design and application of waste heat recovery system for low exhaust gastemperature intelligent diesel main engine.