DEVELOPMENT OF A MATHEMATICAL MODEL FOR CALCULATING HYDRATE FORMATION IN A PIPELINE TAKING INTO ACCOUNT TEMPERATURE CHANGE

Abstract

The development of the main transport of natural gas is of great importance for the economy and industry of the Russian Federation in SHAPE \\* MERGEFORMAT the context of sanctions from the West. Reducing the cost of servicing and eliminating accidents and emergencies is an extremely urgent task that requires a solution with the involvement of modern scientific achievements and discoveries in this area. In this regard, it is necessary to solve a number of tasks that could reduce the risks of accidents and emergencies in the main pipelines caused by the formation of technogenic gas hydrates. The purpose of this study is to develop a mathematical model for calculating the formation of hydrates in the cavity of the main gas pipeline, which would take into account the change in the temperature of the pipeline in the section under consideration, the relief of the route, as well as the carryover of a part of the inhibitor (methanol) by the flow of natural gas. To implement the proposed mathematical model, it is necessary to solve the differential equations proposed in the methodology of Gazprom PJSC for determining the gas temperature. The developed mathematical model should make it possible to reduce the consumption of methanol due to the accuracy of determining the site of the beginning of moisture condensation and supplying the inhibitor to these areas, as well as more accurate determination of the temperature and pressure of natural gas. In this study, the authors obtained an original mathematical model, which is adapted to operating conditions and allows using real data from the operating facility of the Ukhta -Torzhok gas pipeline to calculate the methanol consumption. The authors also take into account the equilibrium content of methanol and water vapors in the «natural gas - watermethanol solution» system in the developed mathematical model, and also introduce certain equations to determine the concentration of methanol that saturates the gas, the concentration of methanol that saturates the liquid, which make it possible to specify the volume of the reagent required for supplying gas to the flow in order to prevent the formation of hydrates and maintain a hydrate-free regime. The authors used a special nomogram to determine the equilibrium content of methanol and water vapors in the «natural gas - water-methanol solution» system, which has become quite widespread at the facilities for transporting hydrocarbon raw materials of Gazprom PJSC. In this paper, the main parameters influencing the formation of hydrates in the pipeline cavity are determined, and the obtained mathematical model is checked for compliance with the real data of the operating object of the main gas pipeline.