通过对各设备进行建模,以某300 MW热电联产机组为例,对热泵供热及利用小型膨胀机发电后排汽供热两种方案进行变工况分析。结果表明,对于热泵供热方案,在不同的主蒸汽流量下,都存在一个最佳出口热网水温,使系统煤耗最低;采用热泵最佳参数与膨胀机方案进行变工况对比,发现在采暖抽汽参数较低时,热泵方案的煤耗高于膨胀机方案,随着采暖抽汽参数的增大,当热泵出口最佳热网水温超过70 ℃时,热泵方案的煤耗开始低于膨胀机方案;同样,在采暖抽汽参数较低时,热泵供热㶲率比膨胀机方案低,当热泵出口最佳热网水温超过64 ℃时,热泵方案供热㶲效率开始超过膨胀机方案;提出等效节能量指标,并通过计算表明该指标可用于对比两方案的节能效益。
Abstract
Heat pump heating and back-pressure expander heating are two common schemes for cascade utilization of extraction steam for heating. However, the off-design characteristics of the two schemes are not clear, and there are few comparative studies between the two schemes. Through modeling for each equipment, taking a 300 MW cogeneration unit as an example, the thermodynamic performances of the two schemes under variable working conditions are analyzed. The results show that for the heat pump heating scheme, there is an optimal outlet temperature under different main steam flow rates corresponding to the lowest coal consumption rate of the system. The heat pump heating scheme with the optimal parameters is compared with the expander heating scheme, it is found that when the extraction steam parameters are low, the coal consumption rate of the heat pump heating scheme is higher than that of the expander heating scheme. With the increase of extraction steam parameters, when the optimal outlet temperature of the heat pump is higher than 70 ℃, the coal consumption of the heat pump heating scheme is lower than that of the expander heating scheme. Similarly, when the extraction steam parameters are low, the heating process exergy efficiency of heat pump heating scheme is lower than that of expander heating scheme. When the optimal outlet temperature of the heat pump exceeds 64 ℃, the heating process exergy efficiency of the heat pump heating scheme begins to exceed that of expander heating scheme. The equivalent energy saving index is proposed, and the calculation results show that the index can be used to compare the energy-saving benefits of the two schemes.
关键词
供热 /
热力学 /
火用 /
梯级利用 /
热泵 /
膨胀机 /
模型
Key words
heating /
thermodynamics /
exergy /
cascade utilization /
heat pump /
expander /
model
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参考文献
[1] 习近平. 在第七十五届联合国大会一般性辩论上的讲话[J]. 中华人民共和国国务院公报, 2020(28): 5-7.
XI J P.Speech at the general debate of the 75th session of the United Nations General Assembly[J]. Gazette of the State Council of the People’s Republic of China, 2020(28): 5-7.
[2] 李晖, 刘栋, 姚丹阳. 面向碳达峰碳中和目标的我国电力系统发展研判[J]. 中国电机工程学报, 2021, 41(18): 6245-6259.
LI H, LIU D, YAO D Y.Analysis and reflection on the development of power system towards the goal of carbon emission peak and varbon neutrality[J]. Proceedings of the CSEE, 2021, 41(18): 6245-6259.
[3] 住房和城乡建设部. 2019年城乡建设统计年鉴[EB/OL]. 北京: 住房和城乡建设部, 2020[2020-12-31]. http://www.mohurd.gov.cn/xytj/index.html.
Ministry of Housing and Urban-Rural Development. Urban-rural construction statistical yearbook(2019)[EB/OL]. Beijing: Ministry of Housing and Urban-Rural Development, 2020[2020-12-31]. http://www.mohurd.gov.cn/xytj/index.html.
[4] 潘杭萍, 杨建明, 王昌朔, 等. 抽汽供热底置式背压汽轮机的运行分析[J]. 汽轮机技术, 2019, 61(5): 361-364.
PAN H P,YANG J M, WANG C S, et al.Operation analysis of bottom backpressure steam turbine in extraction heating[J]. Turbine technology, 2019, 61(5): 361-364.
[5] 周振起, 李晓东, 王涛, 等. 采用凝汽系数法分析喷水减温方式对机组热经济性的影响[J]. 热力发电, 2013, 42(3): 1-4.
ZHOU Z Q,LI X D, WANG T, et al.Exhaust coefficient method based analysis on influence of different spray desuperheating modes on unit thermal economy[J]. Thermal power generation, 2013, 42(3): 1-4.
[6] SUN F T, FU L, SUN J, et al.A new waste heat district heating system with combined heat and power (CHP) based on ejector heat exchangers and absorption heat pumps[J]. Energy, 2014, 69: 516-524.
[7] 李军烁, 沈成喆, 魏书州. 凝汽机组余热余压梯次利用耦合供热系统研究[J]. 热能动力工程, 2020, 35(9): 10-15.
LI J S, SHEN C Z, WEI S Z.Study on cascade further utilization of residual heat and pressure in coupling heating system for large coal-fired condensers[J]. Journal of engineering for thermal energy and power, 2020, 35(9): 10-15.
[8] 和学豪, 赵梓良, 郑磊, 等. 供热抽汽减温水对机组热力性能的影响研究[J]. 热力发电, 2022, 51(2): 98-104.
HE X H, ZHAO Z L, ZHENG L, et al.Study on the influence of desuperheating water of extraction steam on thermal performance of cogeneration units[J]. Thermal power generation, 2022, 51(2): 98-104.
[9] 赵世飞, 戈志华, 陈浩, 等. 增设无再热汽轮机热电联产系统节能研究[J]. 中国电机工程学报, 2016, 36(23): 6441-6447.
ZHAO S F, GE Z H, CHEN H, et al.Energy saving research of a novel combined heat and power system integrating with a non-reheat steam turbine[J]. Proceedings of the CSEE, 2016, 36(23): 6441-6447.
[10] CHEN H, XU J D, XIAO Y, et al.An improved heating system with waste pressure utilization in a combined heat and power unit[J]. Energies, 2018, 11(6): 1515
[11] 王勇, 叶军, 林琳, 等. 基于工业供汽的给水泵背压式汽轮机驱动方案热经济性分析[J]. 热力发电, 2018, 47(10): 103-107.
WANG Y, YE J, LIN L, et al.Thermal economy research on back pressure turbine-driven scheme for feed water pumps based on industrial steam supply[J]. Thermal power generation, 2018, 47(10): 103-107.
[12] 付林, 江亿, 张世钢. 基于Co-ah循环的热电联产集中供热方法[J]. 清华大学学报(自然科学版), 2008, 48(9): 1377-1380.
FU L, JIANG Y, ZHANG S G.District heating system based on Co-ah cycles in combined heating and power systems[J]. Journal of Tsinghua University (science and technology), 2008, 48(9): 1377-1380.
[13] 孙士恩, 田亚, 高新勇. 热泵与低真空耦合回收循环水余热的热力性能分析[J]. 太阳能学报, 2018, 39(5): 1309-1319.
SUN S E, TIAN Y, GAO X Y.Thermodynamic analysis on coupling system of heat-pump and low-vacuum with circulating water heat recovery[J]. Acta energiae solaris sinica, 2018, 39(5): 1309-1319.
[14] 刘浩晨, 耿直, 顾煜炯. 基于膨胀机-热泵(st-hp)的大型吸收式热电联产机组集中供热方法[J]. 化工进展, 2020, 39(2): 468-477.
LIU H C, GENG Z, GU Y J.Central heating supply method of large scale absorption CHP based on st-hp[J]. Chemical industry and engineering progress, 2020, 39(2): 468-477.
[15] 张学镭, 陈海平. 回收循环水余热的热泵供热系统热力性能分析[J]. 中国电机工程学报, 2013, 33(8): 1-8.
ZHANG X L, CHEN H P.Thermodynamic analysis of heat pump heating supply systems with circulating water heat recovery[J]. Proceedings of the CSEE, 2013, 33(8): 1-8.
[16] ASHRAE. 2009 ASHRAE handbook-fundamentals[M]. Atlanta: American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc, 2009.
[17] 郭中旭, 戈志华, 赵世飞, 等. 耦合吸收式热泵机组变工况分析[J]. 热能动力工程, 2018, 33(2): 25-32.
GUO Z X, GE Z H, ZHAO S F, et al.Analysis of the off-design operation conditions of a coupled absorption type heat pump unit[J]. Journal of engineering for thermal energy and power, 2018, 33(2): 25-32.
[18] FARSHI L G, MAHMOUDI S, ROSEN M A.Analysis of crystallization risk in double effect absorption refrigeration systems[J]. Applied thermal engineering, 2011, 31(10):1712-1717.
[19] AZHAR M, SIDDIQUI M A.Comprehensive exergy analysis and optimization of operating parameters for double effect parallel flow absorption refrigeration cycles[J]. Thermal science and engineering progress, 2020, 16: 100464.
[20] WEI J Y, HUA Q, WANG J D, et al.Overview of the development and application of the twin screw expander[J]. Energies, 2020, 13(24): 6586.
[21] LI P C, LI J, TAN R H, et al.Thermo-economic evaluation of an innovative direct steam generation solar power system using screw expanders in a tandem configuration[J]. Applied thermal engineering, 2019, 148: 1007-1017.
[22] LI P C, LI J, GAO G T, et al.Modeling and optimization of solar-powered cascade Rankine cycle system with respect to the characteristics of steam screw expander[J]. Renewable energy, 2017, 112: 398-412.
[23] CHEN H, XIAO Y, XU G, et al.Energy-saving mechanism and parametric analysis of the high back-pressure heating process in a 300 MW coal-fired combined heat and power unit[J]. Applied thermal engineering, 2019, 149: 829-840.
[24] ZHANG Y J, XIONG N, GE Z H, et al.A novel cascade heating system for waste heat recovery in the combined heat and power plant integrating with the steam jet pump[J]. Applied energy, 2020, 278: 115690.
[25] 戈志华, 张倩, 熊念, 等. 330 MW供热机组低压缸近零出力热力性能分析[J]. 化工进展, 2020, 39(9): 3650-3657.
GE Z H,ZHANG Q, XIONG N, et al.Thermal performance analysis of 330 MW heating unit with low pressure cylinder near zero output[J]. Chemical industry and engineering progress, 2020, 39(9): 3650-3657.
[26] 成岭, 张婧, 金璐, 等. LiBr-H2O吸收式热泵的热力学分析[J]. 制冷学报, 2019, 40(1): 128-134.
CHENG L, ZHANG J, JIN L, et al.Thermodynamic analysis of LiBr-H2O absorption heat pump[J]. Journal of refrigeration, 2019, 40(1): 128-134.
[27] ALEXANDER N, ANDREAS B.Investigating a small oil-flooded twin-screw expander for waste-heat utilization in organic Rankine cycle systems[J]. Energies, 2017, 10(7): 869.
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