Obtaining electricity through the utilization of waste heat from gas-pumping aggregates based on a screw expander

Abstract

Relevance: one of the key factors in increasing the energy efficiency of mainline gas transmission systems is the utilization of low-temperature waste heat generated during the operation of gas pumping units. This task becomes especially urgent in conditions of remote trails and limited infrastructure availability, where the rational use of all available resources is of paramount importance.

Aim: the purpose of this study is to develop and feasibility study a method for converting low-potential waste heat into useful electrical energy by introducing a direct thermodynamic cycle using a screw expander.

Methods: to achieve this goal, a thermodynamic modeling technique was used for various direct cycle circuits (including with and without steam overheating), with the selection of a working fluid and the analysis of energy parameters. The characteristics of the compressor station and the operating conditions of the expander have been calculated, including an assessment of thermal efficiency for various configurations.

Results: it has been established that the introduction of a screw expander operating on dry saturated steam can significantly increase thermal efficiency. It is shown that using a superheater reduces the pressure in front of the expander and leads to a threefold decrease in efficiency compared to the basic scheme without steam overheating.