Process Study Of NGL Recovery For No.3 Treatment Plant Of Tahe Oilfield

NGL recovery refers to the process of recovering propane and above components in natural gas in liquid form.Its purpose is not only to control the dew point of hydrocarbon and meet the quality requirements of commercial gas,but also to obtain NGL as much as possible,which has good economic benefits.With the exploration of Tahe oil field,the associated gas production within the managed area of the No.3 treatment station has significantly increased.There are too much heavy components are contained in the associated gas.In order to meet the gas specification of the downstream gas power plant and produce high value-added liquefied gas and stable light hydrocarbon,it is proposed to build a NGL recovery unit with capacity of 50×10~4m~3/d relying on the No.3 Treatment Plant of Tahe oilfield.The purpose of this study is to compare and optimize the NGL recovery process,determine the process flow.Considering the actual situation,the NGL recovery process of"expander+secondary cold resource+DHX"has been adopted,which can obtain qualified natural gas,LPG and stable light hydrocarbon products.The process has the advantages of simple process,reliable operation,less investment and low energy consumption,which can be well adapted to No.3 Treatment Plant of Tahe Oilfield.Aspen HYSYS software has been used to carry out process simulation calculation,analyze the influence of feed gas composition,condensation pressure,condensation temperature,equipment operation parameters and many other factors on propane yield and unit energy consumption,so as to optimize the core operating conditions.Based on the selected process and parameters,the types of main process equipment are compared and determined.The analysis of the process parameters of turbo expansion refrigeration and DHX is helpful to understand the essential characteristic of NGL recovery process,so as to find the key factors to improve yield of propane and reduce energy consumption.It can provide the basis and guidance for the engineering of natural gas processing and follow-up on-site production,operation and management,which can greatly promote the development of NGL recovery industry.