MSR Supercritical Carbon Dioxide Brayton Cycle System and Thermodynamic Analysis
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摘要: 熔盐堆(MSR)能实现在线填料和后处理,出口温度较高,应配备一种与之出口温度相匹配的创新型循环方式,且可达到较高的循环效率。本文基于中国科学院上海应用物理研究所设计的小型模块化熔盐堆(smTMSR-400)设计超临界二氧化碳(SCO2)布雷顿循环系统,使用控制变量法分析了分流比、压缩机/透平效率、主压缩机出口温度、低温换热器换热温差/阻力对SCO2布雷顿循环系统的影响。分析结果表明:①存在最佳分流比使低温换热器两侧温差相等;②相较于压缩机效率,等幅度的透平效率提升可使系统循环效率和㶲效率更高;③主压缩机出口压力增大为系统带来正面影响,但循环效率/㶲效率与其斜率都逐渐降低;④换热器换热温差和流动阻力都为系统循环带来了可量化的负担: 换热温差每增加10 K,循环效率降低1.85%,㶲效率降低2.70%;流动阻力每增加1 MPa,循环效率降低6.58%,㶲效率降低10.22%。最后根据分析结果和系统㶲流变化设计了5种物理参考方案。
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关键词:
- 熔盐堆(MSR) /
- 超临界二氧化碳(SCO2) /
- 布雷顿 /
- 热力学分析
Abstract: Molten salt reactor (MSR) can realize on-line packing and post-processing, and the outlet temperature is higher, so it shall be equipped with an innovative cycle mode that matches its outlet temperature, and can achieve higher cycle efficiency. In this paper, a supercritical carbon dioxide (SCO2) Brayton cycle system is designed based on the small modular molten salt reactor (smTMSR-400) designed by Shanghai Institute of Applied Physics, Chinese Academy of Sciences. The effects of split ratio, compressor/turbine efficiency, outlet temperature of main compressor and heat exchange temperature difference/resistance of low temperature heat exchanger on SCO2 Brayton cycle system are analyzed by using the control variable method. The analysis results show that: ①there is an optimal split ratio to make the temperature difference between the two sides of the low temperature heat exchanger equal; ②compared with the compressor efficiency, the equal-amplitude turbine efficiency improvement can make the system cycle efficiency and exergy efficiency higher; ③ the increase in the outlet pressure of the main compressor has a positive impact on the system, but the cycle efficiency/exergy efficiency and its slope gradually decrease; ④the heat exchange temperature difference and flow resistance of the heat exchanger bring quantifiable burden to the system cycle: for every 10 K increase in the heat exchange temperature difference, the cycle efficiency decreases by 1.85% and exergy efficiency decreases by 2.70%; When the flow resistance increases by 1 MPa, the cycle efficiency decreases by 6.58% and exergy efficiency decreases by 10.22%. At last ,this paper designs 5 physical reference schemes based on the analysis results and system exergy changes.-
Key words:
- MSR /
- SCO2 /
- Brayton /
- Thermodynamic analysis
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表 1 系统初始参数表
Table 1. Initial Parameter Table of System
参数名 参数值 低温换热器低温侧温差/K 40 低温换热器低温侧阻力/kPa 100 高温换热器阻力/kPa 100 预冷器阻力/kPa 100 熔盐换热器阻力/kPa 100 压缩机/透平效率 0.89/0.93 分流比 0.3 功率/MW 400 表 2 主要节点参数表
Table 2. Main Node Parameters
节点参数 参数值 主压缩机入口温度(K)/压力(MPa) 308.2/7.7 主压缩机出口温度(K)/压力(MPa) 370.3/20.0 分流温度(K)/压力(MPa) 410.3/7.8 合流温度(K)/压力(MPa) 527.6/19.9 透平入口温度(K)/压力(MPa) 973.2/19.7 透平出口温度(K)/压力(MPa) 849.4/8 熔盐换热器入口温度(K)/压力(MPa) 776.7/19.8 高温换热器低压侧出口温度(K)/压力(MPa) 572.8/7.9 系统循环效率/% 37.7 系统㶲效率/% 57.0 表 4 物理参考方案
Table 4. Physical Reference Schemes
方案编号 1 2 3 4 5 换热温差/K 20 25 30 35 40 流动阻力/kPa 275 225 175 125 75 压缩机效率/% 93 92 91 90 89 透平效率/% 89 90 91 92 93 分流比 0.321 0.314 0.306 0.297 0.287 预冷器㶲损/% 11.61 12.20 12.70 13.41 14.06 低温换热器㶲损/% 10.50 11.31 12.20 13.09 14.16 高温换热器㶲损/% 14.00 13.28 12.52 11.69 10.70 循环效率/% 43.50 42.54 41.51 40.39 39.11 㶲效率/% 65.72 64.34 62.87 61.23 59.35 -
[1] 魏泉,郭威,王海玲,等. 熔盐堆物理热工耦合程序开发及验证分析[J]. 核技术,2017, 40(10): 100605. [2] 缪洪康,陈玉爽,吕刘帅,等. 板翅式换热器新型翅片换热特性数值模拟研究[J]. 核技术,2018, 41(10): 100601. [3] 黄潇立,王俊峰,臧金光. 超临界二氧化碳布雷顿循环热力学特性研究[J]. 核动力工程,2016, 37(3): 34-38. [4] FEHER E G. The supercritical thermodynamic power cycle[J]. Energy Conversion, 1968, 8(2): 85-90. doi: 10.1016/0013-7480(68)90105-8 [5] ANGELINO G. Carbon dioxide condensation cycles for power production[J]. Journal of Engineering for Gas Turbines and Power, 1968, 90(3): 287-295. [6] LADISLAV V, VACLAV D, ONDREJ B, et al. Pinch point analysis of heat exchangers for supercritical carbon dioxide with gaseous admixtures in CCS systems[J]. Energy Procedia, 2016, 86: 489-499. doi: 10.1016/j.egypro.2016.01.050 [7] DOSTAL V, HEJZLAR P, TODREAS N, et al. Medium-power lead-alloy fast reactor balance-of-plant options[J]. Nuclear Technology, 2004, 147(3): 388-405. doi: 10.13182/NT147-388 [8] DOSTAL V, HEJZLAR P, DRISCOLL M J. High-performance supercritical carbon dioxide cycle for next-generation nuclear reactors[J]. Nuclear Technology, 2006, 154(3): 265-282. doi: 10.13182/NT154-265 [9] DOSTAL V, HEJZLAR P, DRISCOLL M J. The supercritical carbon dioxide power cycle: comparison to other advanced power cycles[J]. Nuclear Technology, 2006, 154(3): 283-301. doi: 10.13182/NT06-A3734 [10] SARKAR J, BHATTACHARYYA S. Optimization of recompression S-CO2 power cycle with reheating[J]. Energy Conversion and Management, 2009, 50(8): 1939-1945. doi: 10.1016/j.enconman.2009.04.015 [11] 刘生晖,黄彦平,刘光旭,等. 不同状态方程对超临界二氧化碳强迫对流传热中流动加速因子的影响[J]. 核动力工程,2019, 40(1): 18-22. [12] 赵新宝,鲁金涛,袁勇,等. 超临界二氧化碳布雷顿循环在发电机组中的应用和关键热端部件选材分析[J]. 中国电机工程学报,2016, 36(1): 154-162. [13] 邹春燕, 余呈刚, 朱贵凤, 等. 利用超铀核素启动的小型模块化钍基熔盐堆中子学性能研究[J]. 核技术, 2020, 43(12): 120601. [14] 杨映麟, 张尧立, 赵英汝, 等. 超临界二氧化碳再压缩布雷顿循环变工况特性分析[J]. 原子能科学技术, 2018, 52(9): 1625-1634