Performance of the steam ejector used for low pressure gas well drainage gas recovery
Zhiyi XIONG1,2*, Yang LIU1,2, Yuan LI3, Hongtao HUANG1,2, Tao LI4
1. College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing 102249, China
2. Beijing Key Laboratory of Process Fluid Filtration and Separation, Beijing 102249, China
3. Sinopec Sichuan to Eastern China Transmission Gas Pipeline Co. Ltd., Wuhan, Hubei 430020, China
4. Beijing Affairs Department of Changqing Oilfield Company, Beijing 100088, China
Abstract：At present, traditional drainage gas recovery technology is not suitable for low-pressure gas wells. In this work, a new type of ejector drainage gas recovery technology was proposed to solve this problem. High-pressure gas was used as a driving fluid to prevent secondary contamination. The problem of low efficiency was solved by forming a composite process with the foam scrubbing, and the ejector was the core of the technology. The aim of this study was to investigate the ejector flow characteristics for gas flow field by Computational Fluid Dynamics (CFD), the entrainment ratio was selected as the performance index, and the influence of ejector structure size and operation condition was obtained. The results showed that the ejection process both of pumping action and shear acceleration action existed in ejection process, and the shear acceleration action only made the ejection fluid to run up to sonic speed. The mass flow rate of ejection fluid was controlled by area and speed together, if the flow area was steady, and the gas speed could not increase in any condition, so that the flow state was in chocking phenomenon. In the chocking condition, the performance of ejector was determined by pumping action. Furthermore, the chocking condition retarded with the increasing of diffused segment conical degree and area ration of the ejector nozzle. In addition, the shear acceleration action played the major role if the flow was not in chocking condition. Operation parameters had an impact on shock wave intensity and ejector flow state, the increasing of operation pressure and the decreasing of outlet pressure would enhance entrainment ratio and cause the chocking condition occur.
熊至宜 刘洋 李元 黄宏韬 李涛. 低压气井排水采气用喷射器的性能[J]. 过程工程学报, 2020, 20(7): 770-778.
Zhiyi XIONG Yang LIU Yuan LI Hongtao HUANG Tao LI. Performance of the steam ejector used for low pressure gas well drainage gas recovery. Chin. J. Process Eng., 2020, 20(7): 770-778.