Natural Gas Turbo Expander Generator Set For Power Generation With Residual Pressure

Natural gas residual pressure turbo-expander generator set

As the throttole valve for process flow depressure in the industrial systems causes such problems as energy loss, increased power consumption, cavitation damage, reduced product ratio and etc., the endusers are looking for a better solution. And the natural gas residual pressure turbo-expander generator set is an ideal option for application in natural gas related plants.

The natural gas residual pressure turbo-expander generator set developed by SMDERI can be applied in natural gas station depressuring, gas turbine power plant pipeline depressuring, pipeline depressuring for plants changing fuel from coal or oil to gas and other cases. It functions to recover the pressure of high pressure natural gas to directly generate electricity or become the power supply to drive other machine. When the turbo-expander works to reduce the pressure, the cold energy produced can be used by the system via heat transfer.

The natural gas entering the volute will evenly distribute the working medium to the nozzle ring along the flow channels inside the volute. After the nozzle, the working medium obtains acceleration and converts the pressure energy into kinetic energy and then it flows to the impeller radially. When the impeller performs external work, the pressure energy and kinetic energy are converted into the kinetic energy of rotor to drive it to run at high speed.

With work effect produced by almost isentropic expansion process of natural in the turbine, the natural residual pressure turbo-expander converts the energy contained in the HP natural flowing into the turbo-expander into mechanical energy and delivers it through the main shaft so as to fulfill the residual pressure recovery.

Similar with other turbo-expander types, the natural residual pressure turbo-expander is also the made up of the turbo-expander, gearbox, generator, lube oil system, measuring system and control system. Owing to the nature of natural gas, a dry gas seal is provided in the turbo-expander to prevent gas leakage and ensure safe operation. Accordingly, related control system is provided for the dry gas seal other than the DCS/PLC.

                                     Fig.1 Natural gas residual pressure turboexpander outline drawing

Based on the inlet pressure, the natural gas turboexpander is divided into 3 series and more details are listed in the form below.