Parametrical Diagnostics of Gas Turbine Performance on Site at Gas Pumping Plants Based on Standard Measurements

Abstract

The operation and maintenance of gas pumping units at the Gazprom transport systems are carried according to the current number of equivalent working hours of the gas turbine and the centrifugal natural gas compressor. Modern concepts of lean production requires maintenance procedures are to be done according to the current technical operating performance of units and its parametrical diagnostics. To meet these requirements an appropriate research project is ongoing at Ural Federal University. In this article a methodology for the technical performance estimation of GTU’s is proposed, verified and discussed. The method is based on processing of data gathered from standard thermodynamic measurements and therefore is applicable in the frame of most gas turbine units without major modifications. The method includes a verified high-order mathematical model based on the Gas dynamic function for the precise analytical description of turbomachinery aerodynamics. A correction factor is introduced for adjusting the mathematical model in case of a non-traditional (not optimised) design applied in the exact turbine design. Models are defined for different types of multi-shaft GT’s and an automated algorithm for calculation of the coefficients of technical performance of the overall unit is provided. A series of experiments showed convergence between traditional and new methods in effective power output and efficiency of units does not exceed 2%. Special software is designed for online monitoring of technical performance.

Technical Condition Estimation of the Gas Turbine Axial Compressor

“…In this study, to assess the technical condition, only the thermogasdynamic parameters noted in figure 2 were used. The processing of the measured parameters and the calculation of the GTU power can be carried out by any known approaches [10][11][12][13][14], in this case, [11] was used. Before analysis, the operational parameters of the gas turbine unit must undergo filtration to exclude transient operating modes of the unit and unreliable measurements.…”

Estimation of the driven gas turbine unit technical performance using the standard measuring systems

“…Any unit can be tested before and after washing [20] or tip clearance recovery in an axial compressor, and, as a result, CTP gain can be defined. The same test series were carried out on marine derivative GTU before and after compressor washing [9].…”

“…This method requires the proper measurement of the natural gas massflow which is not always possible. Gas path analysis methods for gas turbine performance estimation are also used [8,9]. Special attention is paid to the gas turbines with the flow part variable geometry of the power turbine (PT) [10].…”

“…In any case, a gas pumping station remains a very complicated system to have enough measuring facilities and human power for estimation of the real performance of every module, so mathematical models still has opportunities for implementation [2,9].…”

Redesign of an Axial Compressor With Mass Flow Reduction of 30%

“…The value of certain adjustments is dictated by axial speed of the core flow, which is, in turn, a function of pressure ratio of upcoming stages, effective spanwise blockage and compressor efficiency. More detailed approach can be found in [6].…”