船载GT-sCO_(2)双布雷顿联合循环经济分析与多目标优化

Exergoeconomic Analysis and Multi-Objective Optimization of a Marine GT-sCO_(2) Dual Brayton Combined Cycle

为了进一步提高船载动力系统中燃气轮机的效率且降低能源消耗与经济成本,本文对由燃气轮机循环与超临界二氧化碳循环组成的双布雷顿联合循环系统GT-sCO_(2)进行了热力性能与经济性能的分析与优化。对拟建系统进行了[火用]经济分析,选取6个决策变量并研究参数对[火用]效率和单位电力成本两个目标函数的影响。采用基于非支配排序遗传算法的多目标优化方法,对联合循环进行优化以获得最优的系统参数。结果表明,在设计工况下,相对于单一的燃气轮机循环,GT-sCO_(2)联合循环净功率增加了29.44%,[火用]效率提高了29.21%,单位电力成本降低了6.2%,联合循环从热力性能和经济性能上都具有明显优势。联合循环各部件的[火用]损失之和约占总输入[火用]的31.66%,[火用]损失成本占总成本的69.85%,需要优化关键部件的热力参数以提高循环的[火用]经济性。通过控制变量进行的参数研究结果表明,系统[火用]效率及单位电力成本具有不同决策变量的最优值。多目标优化获得联合系统最佳的[火用]效率为48.44%,最佳的单位电力成本为0.292 6元/(kW·h),循环的净输出功率为42 804 kW。本文从热力性和经济性的角度为船舶燃气轮机循环及其余热回收循环的联合性能研究提供参考。

To further improve the efficiency of the gas turbine in shipboard power system and reduce energy consumption and costs, this paper analyzes and optimizes the thermal and economic performance of the gas turbine and supercritical carbon dioxide(GT-sCO_(2)) dual Brayton combined cycle. Firstly, the exergetic and exergoeconomic analyses are conducted for the proposed system;then 6 decision variables are selected and their influence on the two objective functions(namely, exergetic efficiency and unit power cost) is studied;finally, a multi-objective optimization method based on non-dominated sorting genetic algorithm is used to optimize the combined cycle and obtain the optimal system parameters. The results show that under the design conditions, compared with the single gas turbine cycle, the GT-sCO_(2)combined cycle increases the net power by 29.44% and the exergetic efficiency by 29.21%, and decreases the unit power cost by 6.2%, showing obvious advantages in terms of both thermodynamic performance and economic performance. The sum of exergetic loss of all components thereof accounts for 31.66% of the total exergetic input, and the cost of exergetic loss accounts for 69.85% of the total cost. Thermal parameters of key components should be optimized to improve the exergoeconomic performance of the cycle. Parametric studies with variables controlled show that there are possible optimal exergetic efficiency and unit power cost by controlling the decision variables. Through multi-objective optimization, the optimal exergetic efficiency of the combined system is 48.44%, the optimal unit power cost is 0.292 6 yuan/(kW·h), and the net output power is 42 804 kW. This paper provides reference for the performance research on the combined cycle composed of the marine gas turbine cycle and waste heat recovery cycle from the perspective of thermal performance and economic performance.