Simulation and optimization of micro power generation process by utilizing urban natural gas pipeline pressure energy

Transmission pipelines carrying natural gas across long distances often work at high pressures (up to 10 MPa). The high-pressure natural gas is regulated though a throttling device, which results in much waste of pressure energy. Meanwhile, more pressure reducing stations exist the problem of no electric or lack of electric. In this paper, a novel micro power generating process is designed and simulated by Aspen Plus software to utilize the pressure energy. Voltage is selected as the objective function of the process optimization, with several variables. The available energy of whole process is also calculated and discussed. Furthermore, the exergy losses and efficiency are evaluated and analyzed in details. The results showed when the process properly runs, electricity facilities voltage is 220 V, the best expansion ratio range is 3.0 ~ 3.0, the optimal speed range is 650 ~ 750 r/min, the optimal noise range is 71 ~ 72 dB, the corresponding power is 2.6 ~ 2.8 kW. The process capacity is not much, 2 ~ 3 kW output can satisfy the demand of most of the city, to solve the gas pressure regulating stations widespread without electricity, less electricity, and other issues. This process has forward popularization value.