高压单螺杆膨胀机初步性能试验

摘要

In order to recover the pressure energy of the pipeline below 6 MPa in the natural gas letdown station, the high pressure single screw expander ( HPSSE) with a diameter of 117 mm was independently developed in laboratory. The high pressure air was used as the working medium, and the performance of this HPSSE was tested by changing the inlet, outlet pressure and rotational speed. The variation rules of performance parameters were obtained. Results show that the maximum inlet pressure, output power, volumetric efficiency, shaft efficiency, and lowest air-consumption ratio is 5. 8 MPa, 56. 5 kW, 91. 8％, 51. 9％, and 66. 4 kg/( kW·h) , respectively. The volumetric efficiency increased with the increase in the rotational speed, the volumetric efficiency was immensely affected by inlet pressure under fairly slow rotational speed and a slight change in volumetric efficiency was observed under considerably high rotational speed. The shaft efficiency increased with the increase in the rotational speed, and the shaft efficiency initially increased and gradually stabilized thereafter with the increase in the inlet pressure. The HPSSE adopted the axial discharge technology, which relieved the under expansion and extended the high efficient operation area. The experimental results provide technical support for demonstration project of the pressure energy recovery by using HPSSE in the next stage.%为了回收天然气门站中6 MPa以下输气管道的压力能,自主研发了螺杆直径117 mm的高压单螺杆膨胀机.以高压空气为工质对高压单螺杆膨胀机进行了初步性能测试.通过改变高压单螺杆膨胀机进出口压力和转速,得到了各性能参数的变化规律.试验结果表明,高压单螺杆膨胀机的最大进口压力为5.8 MPa、最大输出功率为56.5 kW、容积效率为91.8％,轴效率为51.9％,最小气耗率为66.4 kg/(kW·h);容积效率随着转速的增加而增加,在高转速时,进口压力对其影响较小,低转速时影响较大;轴效率随着转速的增加而增加,随着进口压力的增加先增加后逐步稳定;高压单螺杆膨胀机采用轴向排气技术,减弱了欠膨胀程度,拓宽了膨胀机高效运行范围.通过以上试验性能研究,为下一阶段利用高压单螺杆膨胀机建立压力能回收示范项目提供技术支持.