蒸发壁式超临界水氧化能量回收的模拟研究

Simulation and optimization on energy recovery of the transpiring-wall supercritical water oxidation

为了解决蒸发壁式超临界水氧化(SCWO)反应产物余热回收率低,且相关高压分离参数缺乏的问题,采用有机朗肯循环(ORC)对反应产物余热进行深度回收,利用Aspen Plus建立余热回收及高压分离的模拟流程.研究ORC回收余热过程中运行参数对系统性能(热效率和火用效率)的影响,并探讨温度、压力对反应产物中O_2与CO_2分离的影响规律.研究表明:提高蒸发温度、增大过热度或降低冷凝温度均有利于ORC系统性能的提升,而增大过冷度则会降低系统性能.此外,蒸发温度较高时,采用乏汽回热可显著提升ORC系统性能.当高压分离器温度为30℃～40℃、压力为6～7 MPa时,O_2与CO_2分离效果最佳.采用ORC系统回收反应产物余热可降低SCWO系统能耗,其中ORC系统投资回收期为5.91年.

In order to solve the problems of low waste heat recovery rate in the transpiring wall SCWO system and the lack of relevant high pressure separation parameters, the organic Rankine cycle （ORC） was used to recover the waste heat of the reaction product,and Aspen Plus was used to establish the simulation process of waste heat recovery and high pressure separation. In this paper, the influence of operating parameters on system performance （thermal efficiency and exergy efficiency） during the recovery of ORC waste heat is studied, and the influence of temperature and pressure on the separation of O2 and CO2 from the reac tion products is discussed. The predicted results showed that increasing the evaporation tern perature,increasing the superheat,or lowering the condensing temperature are all beneficial to the improvement of the performance of the ORC system, while increasing the degree of undercooling reduce the system performance. When the evaporating temperature is higher, regenerative exhaust steam can significantly improve system performance. In addition, when the high pressure separatorls temperature and pressure were set to 30 ℃~40 ℃and 6~7 MPa,the separation effect is the best. Using ORC system to recover the waste heat of the reaction product can reduce the energy consumption of the SCWO system, and the ORC system has an investment recovery period of 5.91 years.