Economic and mathematical model of selecting a gas supply system based on biomethane and natural gas

Introduction. A promising direction in the development of gas supply systems, which is widely used in the developed countries of the world, is the use of an alternative energy source — biomethane. The effective use of biomethane requires the development of scientific provisions and recommendations for the use of biomethane gas supply systems, taking into account technical and economic factors. Therefore, it is urgent to develop an economic and mathematical model for choosing a gasification method and determining the area of rational use of gas supply systems with biomethane. Materials and methods. To develop an economic and mathematical model for choosing a method for gasification of settlements, methods of mathematical modeling and parametric optimization were used. The implementation of the economic and mathematical model was carried out in the Mathcad software package. Mathematical and graphic processing of the results obtained was carried out. Results. An economic and mathematical model was developed for determining the rational area of application of biome­thane for gas supply to settlements. The model is based on the technical and economic calculation of the reduced costs for gas supply systems with network natural gas and biomethane. Using the developed model, the technical parameters of the biomethane gas supply system were determined: the critical length of the gas pipeline branch, the radius of the biomethane plant, the biomethane consumption, the length of the gas pipeline for the biomethane supply, and the reduced costs to the gas supply system. A graph of the dependence of the critical length of the gas pipeline branch on the population size has been obtained, which makes it possible to determine the area of rational use of biomethane for gas supply to settlements. It was found that for a rural settlement with a population of 5,000 people, the critical length of the gas pipeline branch is 24.820–28.044 km, for an urban-type settlement with a population of 15,000 people, the length of the gas pipeline branch is 50.923–64.677 km, and for a city with a population of 30,000 people — 89.617–127.279 km. Conclusions. The results obtained can be used for the development and design of gas supply systems based on biomethane for the gasification of settlements remote from the main gas pipelines. The use of biomethane makes it possible to gasify settlements in developed agricultural regions and to increase the efficiency of the gas transportation system of the Russian Federation.