超临界CO_2萃取装置运行不稳定的机理分析及改进措施

Analysis of the unsteadiness causation of running of supercritical CO_2 extraction device and improvement measures

从超临界CO2的BWR方程出发,对萃取系统的CO2压缩过程和节流降压过程进行了热力学分析,指出了超临界CO2萃取装置运行不稳定的原因是液态CO2被压缩时明显的放热升温现象,使加压泵无法正常运行;超临界CO2节流至分离状态时,温度会下降到0℃以下,引起节流阀损坏及下游管道堵塞。提出了设置加压泵冷却系统和节流阀加压系统,来解决系统运行不稳定问题,并用超临界CO2热物性参数计算式,计算了压缩机冷却系统所需冷量及节流阀所需加热量。

On the basis of the BWR equation of supercritical CO2, analyzing the compression and throttling expansion process of supercritical CO2 extraction system in thermodynamic way ,we find the reason of instability in the running process of supercritical CO2 extraction device：the remarkable heat release and temperature rise of liquid COs compressed result in the abnomality running of the pressurization pump; with the throttling the supercritical CO2 to the separation pressue state, the temperature of the supercritical CO2 decrease to 0℃, and this phenomenon cause plugging of the throttle valve and the piping behind it. We make measures for this problem by setting the cooling system of the pressurization pump and the heating system of the throttle valve. Making use of the correlations for thermodynamic character of SCF CO2, we calculate the cooling load of compressor and heating load of throttle valve.