Energy Recovery In A Gas Distribution Station By Combination Of Expanders With Planetary Gear And Optimum Single Valve Control.
The prevailing use of expansion gases in distribution stations can be economically replaced by the application of turbo expanders. The advantage of turbine impulse wheels is that they have high efficiencies, even at very low partial load. With a single valve control easily programmable, seven valve points can be achieved with three control valves. Thereby, throttle losses can be minimized. The design of the valves and their drives can be adapted to the operation requirements. Bearings and couplings are deleted by a combination of expander and gear in one unit, resulting in less power loss, lower investments, and higher availability. The advantages of planetary gears compared to helicals are higher efficiency, smoother running, lower tooth loads, lower noise, and smaller plot plan. This results in secondary advantages such as smaller oil systems, baseplates, and foundations. The disadvantages are higher quality requirements regarding production and more components which, however, are smaller. When an automatic clutch is used, the LP section is shut down as soon as the gas mass flow is zero. The LP section is back into operation within a few seconds after having gas flow. The plant operates fully automatically without operators and maintenance personnel being present at the location. The economic application of expansion turbines used for energy recovery depends not only on a turbine, but on all plant components. The gain of the useful energy is higher than the expenditure of investments, operating costs and maintenance costs. The possibilities of energy recuperation from the natural gas pressure in distributing mains shall be demonstrated by means of an example. The natural gas distribution station of a large German town is supplied from a 41 bar distribution main and transmits the natural gas in two networks of 13 bar or 5 bar. Previously, the natural gas was depressured through throttle valves, and the energy contained in the natural gas was destroyed. Now the gas expansion will be used for the generation of electric energy by the use of expansion turbines.
Beer, Helmut G. H. (1990). Energy Recovery In A Gas Distribution Station By Combination Of Expanders With Planetary Gear And Optimum Single Valve Control.. Texas A&M University. Turbomachinery Laboratories. Available electronically from