Study On The Metering Technology Of Wet Gas Based On Slotted Orifice And Vortex Procession Flowmeter

Wet natural gas flow is a gas-liquid two phase flow with low liquid fractions, there is no commercial wet gas meter in Domestic market. It is one of the major unsolved problems for oil and gas industry.Based on a self developed prototype of wet gas meter and experimental data set, a series of works have been carried out. The main target of this thesis is to develop a fast and efficient data processing method for wet gas meter by Slotted Orifice and Vortex Procession Flowmeter composition.This thesis consists of three parts. The first part is mainly focus on the metering characteristics of slotted orifice, detail analysis about which factor affect slotted orifices over-reading with different beta ratios and pressure. The second part is focus on the metering characteristics of Vortex differential pressure and Precession frequency. The third part is based on Soft measurement techniques with multi-sensor combination to achieve the amount of wet gas flow measurement.Based on the mean value of differential pressure, analysis about which factor affect slotted orifices over-reading with different beta ratios and pressure further. A new correlation for slotted orifice was put forward used TableCurve 3D software and nonlinear regression method. The proposed correlation shows a more accurate calculation results compared with the existing correlations.Based on the mean value of Vortex differential pressure and according to Venturi meter research, proposed a new correlation for test conditions.This thesis uses all phase spectral analysis method to extract precession frequency and analysis about relationship between frequency and two phase flow mass rate. By defining a factor called'Less-Reading', studied about which factor affect'Less-Reading'and proposed a new correlation for Volume flow rate measurement with precession frequency.Through the slotted orifice, vortex differential pressure, precession frequency correlation combination, established the steady-state modelâ… ,â…¡andâ…¢. Based on experimental data, analysis of various steady-state model errors, combined with slotted orifice correlation and precession frequency-dependent correlation, it can be accurately measured gas flow under a certain liquid flow rate condition.Finally, through steady-state model, the instantaneous flow of gas has been tested with LabVIEW software, when the liquid flow rate is less than 1.0m3/h, the gas flow mass rate calculated relative error within 5%.