Thermodynamic analysis of a system to generate electrical energy from the mechanical energy of a natural gas

Abstract

The objective of this work is to design a system for generating electricity from the mechanical energy of a natural gas at high pressure. The main motivation for the development of the research is based on the need to detect by the natural gas distribution industry, where it is considered that the use of the mechanical energy of natural gas (flow energy and kinetic energy) can be used for the Electric power generation, through a turbo expander, and thus power the electromechanical components of a substation. In this way, energy consumption costs are reduced, which translates into unquestionable gains in energy efficiency. The methodology applied is based on the use of physical principles such as the conservation of mass and energy in a control volume. Likewise, the guidelines established in the guideline for the expression of measurement uncertainty allowed us to estimate an interval where the real value of the mechanical power generated at the output of the turboexpander is found. Based on experimental data in a natural gas distribution substation, the consolidated results allowed quantifying the average mechanical power at the inlet of a turboexpander (8155 W) and, in the typical situation where the turboexpander reduces its outlet pressure to 50% , an average mechanical power is generated at the output of the turboexpander equal to 4893 W, which translates into an efficiency of 40%. This research work allowed us to conclude that the design of a system for electric power generation is viable based on the thermodynamic and dimensional parameters associated with the natural gas distribution system, as well as the mechanical power that can be generated at the exit of a turboexpander.