搭建30 kW浅层多级流态化颗粒换热试验台,在约1.5倍临界流化速度、换热器采用直管管束逆流形式布置时颗粒侧换热系数可达590~860 W/（m2·K）。采用双欧拉流体模型对流化床内水平埋管管束换热进行数值模拟,模拟结果与试验结果偏差在10%以内。利用析因设计与线性回归模型研究颗粒粒径、颗粒导热系数和流化气体速度对流态化换热效果的影响。发现颗粒粒径是换热系数的主要影响因素,流化气体速度是次要因素。对于100 MW级太阳能超临界CO2布雷顿循环系统,流态化颗粒换热温度范围为650~900 ℃,换热器热效率约为98.7%,效率约为80.6%,效能约为61.9%,满足设计要求。
Abstract
A lab-scale 30 kW particle heat exchanger of fluidized bed was designed and tested, with straight tube bundles for countercurrent-flow heat exchange. The heat transfer coefficient of particle side reached 590-860 W/（m2·K） at a fluidization speed of 1.5 times of the critical. Euler-Euler Two-Fluid Model was adopted to simulate heat transfer characteristics between fluidizing particles and immersed horizontal tubes. The deviation was within 10% between simulation and experimental results. Factorial design and linear regression model were used to study the effects of particle size, particle thermal conductivity and fluidizing gas velocity on heat transfer. It was found that the particle size was a main factor while the fluidization speed was a minor. As to a 100 MW supercritical CO2 Brayton system of CSP, the temperature range of heat exchanger was 650-900 ℃, and the thermal efficiency was about 98.7%, exergy efficiency was about 80.6%, effectiveness was about 61.9%.
关键词
太阳能热发电 /
流态化换热 /
布雷顿循环 /
超临界 /
CO2 /
试验 /
模拟
Key words
solar thermal power generation /
heat transfer-fluidized beds /
Brayton cycle /
supercritical /
carbon dioxide /
experiments /
simulation
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参考文献
[1] GONZALEZ-ROUBAUD E, PEREZ-OSORIO D, PRIETO C.Review of commercial thermal energy storage in concentrated solar power plants: Steam vs. molten salts[J]. Renewable and sustainable energy reviews, 2017, 80: 133-148.
[2] IRENA. Renewable power generation costs in 2018[R/OL].www.irena.org. International Renewable Energy Agency, Abu Dhabi, 2019.
[3] MEHOS M, TURCHI C, VIDAL J, et al.Concentrating solar power Gen3 demonstration roadmap[R/OL]. www.nrel.gov. NREL/TP-5500-67464, 2017.
[4] TENG L, XUAN Y M.A novel solar receiver for supercritical CO2 brayton cycle[J]. Energy procedia, 2019, 158: 339-344.
[5] IZQUIERDO-BARRIENTOS M A, SOBRINO C, ALMENDROS-IBÁÑEZ J A. Experimental heat transfer coefficients between a surface and fixed and fluidized beds with PCM[J]. Applied thermal engineering, 2015, 78: 373-379.
[6] WEAST T, SHANNON L.Thermal energy storage systems using fluidized bed heat exchangers[R]. DOE/NASA/0096-1, 1980.
[7] GUSTAVSSON M, ALMSTEDT A E.Numerical simulation of fluid dynamics in fluidized beds with horizontal heat exchanger tubes[J]. Chemical engineering science, 2000, 55(4): 857-866.
[8] GOMEZ-GARCIA F, GAUTHIER D, FLAMANT G, et al.Design and performance of a multistage fluidised bed heat exchanger for particle-receiver solar power plants with storage[J]. Applied energy, 2017, 190: 510-523.
[9] BISOGNIN P C, BASTOS J C S C, MEIER H F, et al. Influence of different parameters on the tube-to-bed heat transfer coefficient in a gas-solid fluidized bed heat exchanger[J]. Chemical engineering and processing-process intensification, 2020, 147: 107693.
[10] MA Z W, MARTINEK J.Fluidized-bed heat transfer modeling for the development of particle/supercritical-CO2 heat exchanger[C]//11th ASME International Conference on Energy Sustainability, Charlotte, NC, USA, 2017.
[11] LI S, KONG W B, ZHANG H L, et al.The fluidized bed air heat exchanger in a hybrid Brayton-cycle solar power plant[C]//Solarpaces 2018: International Conference on Concentrating Solar Power and Chemical Energy Systems, Casablanca, Morocco, 2019.
[12] 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.
[13] STEINER P, SCHWAIGER K, WALTER H, et al.Fluidized bed particle heat exchanger for supercritical carbon dioxide power cycles[C]//ASME International Mechanical Engineering Congress and Exposition, Phoenix AZ, USA, 2016.
[14] SULZGRUBER V, WUNSCH D, HAIDER M, et al.Numerical investigation on the flow behavior of a novel fluidization based particle thermal energy storage (FP-TES)[J]. Energy, 2020, 200: 117528.
[15] HO C K, CHRISTIAN J M, ROMANO D, et al.Characterization of particle flow in a free-falling solar particle receiver[J]. Journal of Solar Energy Engineering, 2017, 139(2): 021011.
[16] GUNN D J.Transfer of heat or mass to particles in fixed and fluidised beds[J]. International journal of heat and mass transfer, 1978, 21(4): 467-476.
[17] LEGAWIEC B, ZIOLKOWSKI D.Structure, voidage and effective thermal conductivity of solids within near-wall region of beds packed with spherical pellets in tubes[J]. Chemical engineering science, 1994, 49(15): 2513-2520.
[18] 岑可法. 循环流化床锅炉理论设计与运行[M]. 北京: 中国电力出版社, 1998.
CEN K F.Theoretical design and operation of circulating fluidized bed boiler[M]. Beijing: China Electric Power Press, 1998.
[19] 王勤辉, 骆仲泱, 倪明江, 等. 循环流化床内颗粒停留时间分布[J]. 燃烧科学与技术, 2001, 7(4): 221-225.
WANG Q H, LUO Z Y, NI M J, et al.Particle residence time distribution in a circulating fluidized bed[J]. Journal of combustion science and technology, 2001, 7(4): 221-225.
[20] GOMEZ-GARCIA F, GAUTHIER D, FLAMANT G.Design and performance of a multistage fluidised bed heat exchanger for particle-receiver solar power plants with storage[J]. Applied energy, 2017, 190: 510-523.
[21] 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.
基金
浙江省杰出青年基金（LR20E060001）; 国家重点研发计划（2018YFB1501002）
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