Process and device for generating power by pressure energy of small natural gas pipeline network

The invention discloses a process and a device for generating power by pressure energy of a small natural gas pipeline network. A high-pressure pipeline network of the device is connected with a gas inlet of an expansion machine through a pipeline; a gas outlet of the expansion machine is connected with a gas inlet of a temperature balancer through a pipeline; an outlet of the temperature balancer is connected with a low and medium-pressure gas pipeline network through a pipeline; a main shaft of the expansion machine is connected with a gearbox; the gearbox is connected with a power generator; the power generator is connected with a transformer synchronizer; the expansion machine adopts an improved AT15-65 type gas expansion machine; one end of the main shaft is connected with an air cylinder in a totally-closed way; a first seal ring and a second seal ring, which have sealing effects, are arranged between the other end of the main shaft and a wheel drum; a flow guide pipe is arranged in a closed cavity between the two seal rings; the flow guide pipe is connected with an inert gas bottle. The device can be used for continuously and stably providing a 220 V/380 V stable power supply for an interruptible and closed 1-5 kW low-power user.