Slobodian N. Methods and measures improvement to increase main gas pipelines hydraulic efficiency

The dissertation is devoted to the improvement of methods and measures to increase the hydraulic efficiency of main gas pipelines and gas transmission systems, taking into account the physical properties of deposits in the pipe cavity when planning and optimizing the cleaning process. The obtained results make it possible to increase the coefficient of hydraulic efficiency and ensure a high degree of cleaning of existing main gas pipelines. The paper considers modern methods of increasing the efficiency of pipeline transport cleaning. The most effective method of increasing the efficiency of the pipeline is its periodic cleaning using mechanical cleaning devices. The reasons for the decrease in efficiency are the presence of liquid in the cavity of the pipeline, which can be in two forms - high-viscosity resin deposits and low-viscosity liquid deposits. Deposits reduce the cross-sectional area and increase the hydraulic resistance. Regardless of the design of the treatment plant, none of them can completely remove liquid contaminants. The causes of overflows across the moving boundary, which lead to the deterioration of the quality of gas pipeline cleaning, are analyzed. The influence of physical properties of liquids on the process of purification of main gas pipelines from liquid accumulations is investigated. A formula for calculating the correction factor, which takes into account the rheological properties of the liquid. The optimal speed of the purification device, which depends on the properties and rheology of the non-Newtonian fluid, is determined. The estimation of speed change of the clearing device movement at change of the main gas pipeline technological scheme is carried out. The mathematical model of process on the basis of which regularities of the clearing device movement at change of the gas pipeline technological scheme, is established is constructed. An algorithm has been developed and a program for calculating the degree of reduction of the piston speed depending on the type of technological parameters and technical characteristics of the treatment device and the pipeline has been developed. An algorithm for increasing the efficiency of pipeline cleaning is proposed, which is based on the reduction of flows through the moving boundary when expelling liquid from the pipeline by a cleaning piston by aeration of liquid contaminants. The influence of the gas content of liquid accumulations on the amount of flows into the space behind the piston is established. A mathematical model of the process is constructed, on the basis of the realization of which the regularities of pressure fluctuations in a gas - liquid medium are established. The process of gas transmission systems cleaning with the help of cleaning pistons is technologically complex and expensive. Therefore, when planning it is necessary to create all the conditions that would ensure maximum cleaning efficiency and be cost-effective. Increasing the number of cleanings of gas transmission systems increases their hydraulic efficiency, which leads to an increase in profits of gas transmission organizations. As a result, the cost of cleaning increases, which leads to a decrease in profits of gas transmission companies. Therefore, the number of cleanings of gas pipelines and gas transmission systems should be equal to the optimal number of cleanings for a certain period of time. Assessment indicators of economic efficiency of internal cavity cleaning measures of gas pipelines are analyzed. It is established that a more specific indicator of the assessment of gas pipeline cleaning measures is the increase in the total profit of the gas transmission company. The dependence of the profit of the gas transportation enterprise on the number of cleanings of the gas pipeline for a certain period of time is investigated. A method for determining the optimal frequency of gas transmission systems cleaning has been developed. A mathematical model of the process is built, on the basis of which a transcendental equation is obtained to find the optimal number of cleanings of gas transmission systems for a certain period of operation. A graphoanalytical method for its solution is proposed.