Analysis of Residual Pressure Power Generation in Natural Gas Pressure Regulating Station

Abstract

Turboexpander, placed parallel to the regulator in natural gas pressure regulating station (PRS), was proposed to utilize the residual pressure by engineers and researchers. However, the relationship between the power generated by the turboexpander and the energy used to preheat the natural gas (NG) needs to be carefully analysed. This article estimated the electric power that could be generated using residual pressure based on an actual PRS in China. An analysis model was established to study the relationship between electric power generated by the turboexpander and energy used to preheat the NG. Pressures both inlet and outlet and inlet temperature of the established power generation model were carefully analysed as well as the natural gas hydrate formation temperature. The results indicate that the electric power generated by the turbine expander and the energy used to preheat natural gas decrease as the pressure difference decreases. Most of the energy needed to preheat NG in the procedure of PRS can be obtained through the established turboexpander. What’s more, residual electric power can be obtained when the difference pressure is less than the critical point in which the energy used to preheat NG is equal to the energy generated by the turboexpander.