Five configurations of the S-CO2 Brayton cycle (SCBC) were constructed for flue gas waste heat recovery (WHR) of the marine low-speed engine HHM-6EX340EF on the EBSILON platform using the bench test data to save energy, reduce emissions and the efficient operation of ocean-going vessels. Experimental data from Sandia National Laboratories (SNL) was utilised to validate the accuracy of the model and the effect of Brayton cycle parameters on flue gas WHR for different configurations was analysed. The parameters of the SCRBC (S-CO2 recompression Brayton cycle) were optimised by combining the Neural Network Fitting (NNF) model, Multi-objective optimisation algorithms, and multi-criteria decision-making methods. Finally, the thermodynamic analysis of the low-speed engine was comprehensively evaluated by comparing five configurations of SCSBC (S-CO2 simple Brayton cycle), SCCBC (S-CO2 recuperative Brayton cycle), SCHBC (S-CO2 reheating Brayton cycle), SCIBC (S-CO2 intercooling Brayton cycle), and SCRBC. The optimised SCIBC configuration had the highest net recuperated work of 195.76 kW and the highest Brayton cycle efficiency of 20.13 %. The engine efficiency was improved by 0.82 %, 1.45 %, 1.78 %, 1.86 % and 1.68 %, the BSFC was decreased by 3.20 g/kW·h, 5.56 g/kW·h, 6.82 g/kW·h, 7.04 g/kW·h, and 6.43 g/kW·h, and the output power increased by 86.90 kW, 153.33 kW, 195.76 kW, 189.36 kW, and 178.14 kW, respectively. The maximum exergy loss of the cooler was 162.67 kW with an exergy loss efficiency of 14.54 % in the SCSBC configuration. Optimising the flue gas heat exchanger and cooler will further enhance the efficiency and reduce emissions. Research on the parameter and configuration optimisation of the SCBC for marine low-speed diesel engines can be extended to other low-speed engines.

中文翻译：

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船用低速发动机烟气S-CO2布雷顿循环设计、优化与评价


利用台架试验数据，在EBSILON平台上构建了五种S-CO2布雷顿循环（SCBC）配置，用于船用低速发动机HHM-6EX340EF的烟气余热回收（WHR），以达到节能减排和降低排放的目的。远洋船舶的高效运营。利用桑迪亚国家实验室（SNL）的实验数据验证了模型的准确性，并分析了不同配置下布雷顿循环参数对烟气余热比的影响。结合神经网络拟合（NNF）模型、多目标优化算法和多准则决策方法对SCRBC（S-CO2再压缩布雷顿循环）参数进行优化。最后，通过比较SCSBC（S-CO2简单布雷顿循环）、SCCBC（S-CO2回热式布雷顿循环）、SCHBC（S-CO2再热布雷顿循环）、SCIBC五种构型，对低速发动机的热力学分析进行了综合评估。 （S-CO2 中冷布雷顿循环）和 SCRBC。优化后的 SCIBC 配置具有最高的净回收功 195.76 kW 和最高的布雷顿循环效率 20.13%。发动机效率分别提高0.82%、1.45%、1.78%、1.86%和1.68%，BSFC降低3.20g/kW·h、5.56g/kW·h、6.82g/kW·h、7.04g/ kW·h和6.43 g/kW·h，输出功率分别增加86.90 kW、153.33 kW、195.76 kW、189.36 kW和178.14 kW。 SCSBC 配置中冷却器的最大火用损失为 162.67 kW，火用损失效率为 14.54%。优化烟气换热器和冷却器将进一步提高效率并减少排放。 船用低速柴油机SCBC参数及配置优化研究可推广到其他低速柴油机。