Host Energy Consumption Distribution Of 72000DWT Oil Tanker And Establishment Of Evaluation Index Of Energy Efficiency

As the increasingly severe in environment pollution, the demand of engine emissions control is higher and higher around the world, which promotes the dramatically strict in engine emission regulations making. The operating activities of ship at sea are strong liquidity, diffusivity, long lasting. At the same time, with the development of marine and constantly strict emission regulations of land mobile machinery, ship diesel engine exhaust emissions rate is rising in recent years. Therefore, it is of great importance in ships energy saving technology and ship energy efficiency evaluation to the establishment of Ships energy distributed computing and ships energy distributed computing.Take the instantaneity of Ships energy consumption calculation and the limitation of the real-ship measurement parameters into consideration, based on the distribution of phase and Seiliger circulation and average method, this paper use a 72000 DWT oil tanker as the research object, establishing the model of thermal performance calculation in ship main propulsion system step by step. According to the different crank angle of cylinder switching,refining the inside thermal process of the cylinder: polytropic compression, constant volume combustion Isobaric heat, polytropic expansion and ventilation. We calculate the key parameters of performance in different conditions of each stage. Using the first law of thermodynamics to build the model of energy distribution in ship main propulsion system,calculating the host power and cooling loss, high temperature exhaust gas loss and heat loss under different working conditions. Find out the large part of energy consumption, mining the potential of energy saving combined with the ship waste heat recovery. Establish evaluation system of comprehensive energy efficiency of the three main ship type vessel based on the entropy method and AHP method (AI IP method).Take thermodynamic parameters calculation under the conditions of 100%, 70%, 40%,comparing with the designed data, the errors of thermal performance parameters are under 5%, which means the accuracy of the model is verified. From the energy consumption, the host power rate is 47.15% under the condition of 100%, heat losing of smoke vent is 40.48%, the heat loss rate of cooling system is 9.92%. The recovery rate of waste heat is 7.73%, in which the recovery rate of light jacket water system, the HRSG and the turbo-charging are 3.45%,3.01% and 1.27%. With the reduction of the load in different work condition, the host cycle time increases from 0.57s under 100% operating condition to 0.78s of 40%; effective power of host decreases, cylinder cooling loss also decreases, as the temperature and flow of exhaust gas falls, the loss of smoke extraction reduced as well; the temperature of exhaust in gas turbine outlet decreases first and then increases, the minimum is 489.99K under 80% condition. In addition, in view of the important position of EEDI in the evaluation of ship energy saving, come up with two projects. Case 1 included direct parameters' method, relative factors' method, and subjective grading method, were scored 0.390,0.589,0.021. Case 2 included the technical, economic and environment, which were scored 0.480,0.490,0.031.Through results analysis, we have better understanding and implementation plan on the energy-saving potential of vessel at sea. The large energy consumption parts have great energy-saving potential. This provides reference for future analysis on the energy consumption of other systems in different ship types.