Modeling of the modes of natural gas transportation by main gas pipelines in the conditions of underloading

Abstract

The current state of transit of natural gas through the Ukrainian gas transmission system (GTS) is estimated in the paper. The prerequisites for further reduction of the GTS load in the coming years are considered, in particular in the direction of Europe through the gas measuring station "Orlivka" (south direction), taking into account the construction of alternative bypass gas pipelines. On the basis of the review of literature sources on the problem of efficient operation of gas pipelines under conditions of underloading, a method for determining the capacity and energy consumption of the gas pipeline for a given combination of working gas pumping units (GPU) was developed. The Ananyev-Tiraspol-Izmail gas pipeline at Tarutino-Orlivka section was selected as the object of research. The methodology includes the calculation of the physical properties of gas by its composition, the calculation of gas compression, the calculation of the linear part, the gas flow to the compressor station's own needs, and the calculation of the total power of the gas-pumping units under the specified technological limitations. With the help of the original software developed in the MATLAB programming language, cyclical multivariate calculations of the capacity and energy consumption of the gas pipeline were carried out and the operating modes of the compressor shop were optimized in the load range from 23 ... 60 million m3/day. Optimization criterion is the minimum total capacity of the GPU. Variable parameters at the same time are the speeds of the superchargers, different combination of working GPU, load factor. According to the results of the optimization graphical dependences were constructed: the optimum frequency of the rotor of the supercharger on the performance of the pipeline; changes in power and pressure depending on the performance of the pipeline when operating a different combination of superchargers. Recommendations have been developed to minimize fuel gas costs at the compressor station.