基于太阳能颗粒集热的超临界CO_2流化床换热器模拟研究
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摘要
基于太阳能颗粒集热的超临界CO_2布雷顿循环系统效率高,发展潜力巨大。本文应用更加精确的颗粒侧传热模型,构建了超临界CO_2流化床换热器模型,以100 kW换热功率的换热器工况参数为基础,对传热管外径尺寸、管束数量、颗粒粒径和流化气体温度进行优化。结果表明:在满足CO_2流动压损为0.01MPa的条件下,优化后换热器的管束参数为管外径10 mm,壁厚2.9 mm,管束数量97根;选择小粒径颗粒时,临界流化速度较低、流量较小,可以有效降低气体热损失,提高换热器热效率和降低风机能耗,优化管束参数条件下,当颗粒粒径从100μm增至500μm时,气体热损失从70.32 W增至1 176.00 W,热效率从99.93%降至98.84%,风机能耗从21.60 W增至405.97 W;流化气体入口温度从570℃提高到630℃,换热器热效率从98.52%提升至99.64%。
With high thermal efficiency, the supercritical CO_2 Brayton cycle system based on solar particle-receiver has great development potential. By applying a more accurate particle-side heat transfer model, the supercritical CO_2 fluidized bed heat exchanger model is established. On the basis of the operating parameters of the heat exchanger with 100 kW heat transfer power, the external diameter, tube bundle number, particle size and fluidized gas temperature of the heat transfer pipes are optimized. The results show that, under the condition that the flow pressure loss of CO_2 is 0.01 MPa, the optimized tube bundle parameters of the heat exchanger are as follows: the outer diameter of the tube is 10 mm, the thickness of the tube is 2.9 mm, the number of the tubes is 97. When the small particle size particles are selected, the critical fluidization velocity is low, the flow rate is small, so the heat loss of the gas can be effectively reduced, the heat efficiency of the heat exchanger can be improved, and the energy consumption of the fan can be decreased. With the optimized tube bundle parameters, when the particle size increases from 100 μm to 500 μm, the heat loss increases from 70.32 W to 1 176.00 W, the thermal efficiency declines from 99.93% to 98.84%, the fan power consumption increases from 21.60 W to 405.97 W, the inlet temperature of the fluidized gas rises from 570 ℃to 630 ℃, and the thermal efficiency of the heat exchanger increases from 98.52% to 99.64%.
With high thermal efficiency, the supercritical CO_2 Brayton cycle system based on solar particle-receiver has great development potential. By applying a more accurate particle-side heat transfer model, the supercritical CO_2 fluidized bed heat exchanger model is established. On the basis of the operating parameters of the heat exchanger with 100 kW heat transfer power, the external diameter, tube bundle number, particle size and fluidized gas temperature of the heat transfer pipes are optimized. The results show that, under the condition that the flow pressure loss of CO_2 is 0.01 MPa, the optimized tube bundle parameters of the heat exchanger are as follows: the outer diameter of the tube is 10 mm, the thickness of the tube is 2.9 mm, the number of the tubes is 97. When the small particle size particles are selected, the critical fluidization velocity is low, the flow rate is small, so the heat loss of the gas can be effectively reduced, the heat efficiency of the heat exchanger can be improved, and the energy consumption of the fan can be decreased. With the optimized tube bundle parameters, when the particle size increases from 100 μm to 500 μm, the heat loss increases from 70.32 W to 1 176.00 W, the thermal efficiency declines from 99.93% to 98.84%, the fan power consumption increases from 21.60 W to 405.97 W, the inlet temperature of the fluidized gas rises from 570 ℃to 630 ℃, and the thermal efficiency of the heat exchanger increases from 98.52% to 99.64%.
引文
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[8] STEINER P, SCHWAIGER K, WALTER H, et al.Fluidized bed particle heat exchanger for supercritical carbon dioxide power cycles[C]//ASME 2016. ASME International Mechanical Engineering Congress and Exposition, Volume 14:Emerging Technologies; Materials:Genetics to Structures, Safety Engineering and Risk Analysis:V014T07A014. DOI:10.1115/IMECE 2016-67104.
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[10] GOMEZ-GARCIA F, GAUTHIER D, FLAMANT G.Design and performance of a multistage fluidized bed heat exchanger for particle-receiver solar power plants with storage[J]. Applied Energy, 2017, 190:510-523.
[11] HO C K. Characterization of particle flow in a freefalling solar particle receiver[C]//ASME 2015. ASME 2015 9th International Conference on Energy Sustainability, ES2015, collocated with the ASME 2015 Power Conference,the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. 2015.
[12] KIM S W, AHN J Y, KIM S D, et al. Heat transfer and bubble characteristics in a fluidized bed with immersed horizontal tube bundle[J]. International Journal of Heat and Mass Transfer, 2003, 46(3):399-409.
[13] BOISSIERE B, ANSART R, GAUTHIER D, et al.Experimental hydrodynamic study of gas-particle dense suspension upward flow for application as new heat transfer and storage fluid[J]. The Canadian Journal of Chemical Engineering, 2015, 93(2):317-330.
[14] THONGLIMP V, HIQUILY N, LAGUERIE C. Vitesse minimale de fluidisation et expansion des couches fluidisées par un gaz[J]. Powder Technology, 1984,38(3):233-253.
[15] MICKLEY H S, FAIRBANKS D F. Mechanism of heat transfer to fluidized beds[J]. Aiche Journal, 1955, 1(3):374-384.
[16] OZKAYNAK T F, CHEN J C. Emulsion phase residence time and its use in heat transfer models in fluidized beds[J]. Aiche Journal, 1980, 26(4):544-550.
[17] BASKAKOV A P, BERG B V, VITT O K, et al. Heat transfer to objects immersed in fluidized beds[J]. Powder Technology, 1973, 8(5):273-282.
[18] SAXENA S C. Heat transfer between immersed surfaces and gas-fluidized beds[J]. Advances in Heat Transfer,1989, 19:97-190.
[19] KUNII D, LEVENSPIE O. Fluidization engineering[M].USA:Butterworth-Heinemann, 1991:313-336.
[20] GNIELINSKI V. On heat transfer in tubes[J]. International Journal of Heat&Mass Transfer, 2013, 63(3):134-140.
[21] ERGUN S. Fluid flow through packed columns[J].Chemical Engineering Progress, 1952, 48:89-94
[2] HO CLIFFORD K. A review of high-temperature particle receivers for concentrating solar power[J]. Applied Thermal Engineering, 2016, 109:958-969.
[3] BAUMANN T, ZUNFT S. Development and performance assessment of a moving bed heat exchanger for solar central receiver power plants[J]. Energy Procedia, 2015,69:748-757.
[4] ALBRECHT K J, HO C K. Heat transfer models of moving packed-bed particle-to-SCO2 heat exchangers[C].ASME 2017 11th International Conference on Energy Sustainabilit:V001T05A006. DOI:10.1115/ES2017-3377.
[5] WEAST T, SHANNON L. Thermal energy storage systems using fluidized bed heat exchangers[R]. Report NASA-CR-159868, DOE/NASA/0096-1, 1980.
[6] STEINER P. Experimental investigations and application analysis of a particle-based high temperature thermal energy storage[D].Wien:TU Wien, 2017:50.
[7] SCHWAIGER K, HAIDER M, HAEMMERLE M, et al. Fluidized bed steam generators for direct particle absorption CSP-plants[J]. Energy Procedia, 2015, 69:1421-1430.
[8] STEINER P, SCHWAIGER K, WALTER H, et al.Fluidized bed particle heat exchanger for supercritical carbon dioxide power cycles[C]//ASME 2016. ASME International Mechanical Engineering Congress and Exposition, Volume 14:Emerging Technologies; Materials:Genetics to Structures, Safety Engineering and Risk Analysis:V014T07A014. DOI:10.1115/IMECE 2016-67104.
[9] MA Z, MARTINEK J. Fluidized-bed heat transfer modeling for the development of particle/supercritical-CO2 heat exchanger[C]//ASME 2017. ASME 2017 11th International Conference on Energy Sustainability:V001T05A002.DOI:10.1115/ES2017-3098.
[10] GOMEZ-GARCIA F, GAUTHIER D, FLAMANT G.Design and performance of a multistage fluidized bed heat exchanger for particle-receiver solar power plants with storage[J]. Applied Energy, 2017, 190:510-523.
[11] HO C K. Characterization of particle flow in a freefalling solar particle receiver[C]//ASME 2015. ASME 2015 9th International Conference on Energy Sustainability, ES2015, collocated with the ASME 2015 Power Conference,the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. 2015.
[12] KIM S W, AHN J Y, KIM S D, et al. Heat transfer and bubble characteristics in a fluidized bed with immersed horizontal tube bundle[J]. International Journal of Heat and Mass Transfer, 2003, 46(3):399-409.
[13] BOISSIERE B, ANSART R, GAUTHIER D, et al.Experimental hydrodynamic study of gas-particle dense suspension upward flow for application as new heat transfer and storage fluid[J]. The Canadian Journal of Chemical Engineering, 2015, 93(2):317-330.
[14] THONGLIMP V, HIQUILY N, LAGUERIE C. Vitesse minimale de fluidisation et expansion des couches fluidisées par un gaz[J]. Powder Technology, 1984,38(3):233-253.
[15] MICKLEY H S, FAIRBANKS D F. Mechanism of heat transfer to fluidized beds[J]. Aiche Journal, 1955, 1(3):374-384.
[16] OZKAYNAK T F, CHEN J C. Emulsion phase residence time and its use in heat transfer models in fluidized beds[J]. Aiche Journal, 1980, 26(4):544-550.
[17] BASKAKOV A P, BERG B V, VITT O K, et al. Heat transfer to objects immersed in fluidized beds[J]. Powder Technology, 1973, 8(5):273-282.
[18] SAXENA S C. Heat transfer between immersed surfaces and gas-fluidized beds[J]. Advances in Heat Transfer,1989, 19:97-190.
[19] KUNII D, LEVENSPIE O. Fluidization engineering[M].USA:Butterworth-Heinemann, 1991:313-336.
[20] GNIELINSKI V. On heat transfer in tubes[J]. International Journal of Heat&Mass Transfer, 2013, 63(3):134-140.
[21] ERGUN S. Fluid flow through packed columns[J].Chemical Engineering Progress, 1952, 48:89-94