低温蒸汽联合回热ORC系统变工况热效率的优化

Optimization of Heat Utilization Efficiency in Low Temperature Steam Combined Regeneration ORC System under Variable Working Conditions

为研究变工况下抽汽-乏汽联合回热系统的热力性能,建立热源与冷源变化的联合回热系统模型,对不同抽汽压力、不同回热器效能下系统热力性能随热源温度T_g与冷源温度T_0变化的规律进行分析,并在变工况下对不同回热循环系统的热力性能进行比较。结果表明:在不同抽汽压力与回热器效能下,系统净输出功、热效率均随热源温度升高不断增加,效率存在一最佳值;系统各热力性能随冷源温度增加则不断降低;在变工况下,当热源温度较高或冷源温度较低时增加抽汽回热、乏汽回热效果显著,在热源温度T_g=140℃,冷源温度T_0=10℃时,其热效率分别比其他三种循环(抽汽回热系统、乏汽回热系统、无回热系统)高1.03%、1.13%及2.78%,同时,热源与冷源温度增加,最佳抽汽压力增大,反之降低。

In order to study the thermal performance of extracted-exhausted combined regenerative system,the combined regenerative ORC system model which have variable heat and cold source has been established based on the laws of thermodynamics.The change law of system thermal performance under different regenerator effectiveness and extraction steam pressure with heat source temperature（T_g） and cold source temperature（T_0） is analyzed,with the thermal performance of different regenerative cycle system under variable working conditions compared.The result shows that the net output work,thermal efficiency increases with the heat source temperature while the energy efficiency had an optimum value; as for the cold source,the performance decreases.Compared to other system,the efficiency of combined regenerative system are improved by 1.03% 、1.13% 、2.78% under the condition which T_g is 140℃ and T_0 is 10℃ at the same time,the optimum extraction pressure increases with the temperature of heat and cold sources,otherwise reduces.