RU38802U1 - TURBO-EXPANDER POWER PLANT - Google Patents

Abstract

A turboexpander power plant belongs to power engineering and can be used to create small power plants to generate electricity through the energy of compressed natural gas. The device comprises an electric generator, on the shaft of which the impellers of the turboexpander are cantilevered from both ends so that the axial forces from the gas-dynamic forces are subtracted. Therefore, the axial load on the thrust bearing is reduced. And this leads to an increase in the resource of the bearing and the entire device. High pressure natural gas is used to lubricate bearings. Cold natural gas of low pressure after it leaves the turbine expander is used to cool the generator. In this case, the gas is heated to a temperature in a predetermined interval.

Description

The utility model relates to power engineering and can be used to create small power plants to generate electricity through the energy of compressed natural gas.

Known turboexpander power plants containing an electric generator with a multi-stage turboexpander installed on a high-pressure natural gas pipeline, - [1]. Also known are gas turbine units, the impellers of which are located on the rotor shaft of the electric generator cantilever, - [2] (prototype).

However, the known devices in the first case have a significant axial force on the rotor, which reduces the resource of the thrust bearing and the device as a whole, and in the second case, the turbine impeller is cantilevered on one side of the generator shaft. At the same time, the second end of the shaft is not used to place the impeller, or wheels, of the turbine, which reduces the possibility of a significant pressure drop occurring on the turbine when using high pressure natural gas as a working fluid on the turbine. In addition, high pressure natural gas is not used as a lubricant on known devices, and low-temperature natural gas is not used as a cooling medium after it has passed through turbine expander stages.

The objective of the proposed device is to reduce the axial force on the thrust bearing in order to increase the resource, as well as using natural gas as a lubricant (for bearings) and a cooling medium (for an electric generator).

This is achieved by the following innovations. One or more impellers of the first stages of the turboexpander are placed cantilever on one of the ends of the generator shaft. And one or several impellers of the subsequent stages of the turboexpander are placed cantilever on the other end of the generator shaft. Gas flows on the blades of the impellers on

the mentioned groups have the opposite direction. Therefore, axial forces are subtracted. Through the rotor shaft of the generator, the axial force difference arising on the two groups of impellers acts on the thrust bearing. On the high-pressure natural gas pipeline, a lubrication line for bearing lubrication is provided. And after passing through the turboexpander, the cooled natural gas is fed into the annular cavity between the casing and the casing to cool the generator. The natural gas warmed up from the electric generator then goes to the highway for its supply to the consumer.

These innovations give the following technical result. The thrust bearing of the rotor of the electric generator unloaded from the axial force has an increased resource, which increases the resource of the product as a whole. In addition, the use of high pressure natural gas bearings as a lubricant simplifies the lubrication system. And cold natural gas after the turboexpander, on the one hand, cools the generator, and on the other hand it warms up itself and removes the problem of heating it before being sent to the consumer, since there are known limitations on the temperature of the natural gas supplied to the consumer.

The proposed device is illustrated in the drawing, which shows a longitudinal section of a turboexpander power plant.

The turboexpander power station contains an electric generator 1 with a housing 2 and a rotor 3 and a two-stage turboexpander with impellers 4 and 5 located cantilever on the shaft of the rotor 3 of the electric generator 1. Arrows IN and OUT indicate the places where natural gas enters the turbine expander and leaves it in the main for supply to the consumer.

On the body 2 there is a fitting 6 for supplying high-pressure natural gas to the gas-static support 7 of the rotor 3 of the electric generator 1. The same fitting is available for supplying natural gas to the gas-static support 8.

The curved arrow in the drawing indicates the direction of movement of natural gas from the impeller 5 of the turboexpander into the annular cavity 9 between the housing 2 and the casing 10 and further into the exhaust pipe 11.

In operation, natural gas is supplied through the nozzles 12 and 13, the annular cavity 14 and the nozzle apparatus 15 to the impeller 4 of the turboexpander. After the impeller 4, natural gas enters the annular cavity 16 and then through pipes 17 and 18 into the annular cavity 19. From the annular cavity 19 through the nozzle apparatus 20

natural gas enters the impeller 5 of the turboexpander. From the impeller 5 it is fed into the annular cavity 9 and then into the exhaust pipe 11. Passing through the impellers 4 and 5, natural gas converts the pressure energy into mechanical energy of rotation of the rotor 3 of the generator 1. At the same time, the temperature of the natural gas decreases. Cold gas during the passage of the annular cavity 9 cools the generator 1 and is heated itself. The fitting 6 is connected to a high-pressure natural gas pipeline. Gas is supplied through a nozzle 6 and another similar nozzle to lubricate the gas-static supports 7 and 8. After passing the gas-static supports 7 and 8, natural gas enters the internal cavity 21 of the electric generator 1, cools the electric generator, and then passes through the openings 22 into the annular cavity 9 and into the exhaust nozzle 11.

Claims (3)

1. A turboexpander power plant comprising an electric generator with a multi-stage turboexpander having an inlet pipe or inlet pipes connected to a high-pressure natural gas line and an exhaust pipe connected to a natural gas supply line to the consumer, and the turbine-expander impellers are located on a cantilever rotor shaft, characterized in that the impeller of the first stage or several impellers of the front stages of the turboexpander are fixed at one end of the shaft, and one or ultiple subsequent stages of impellers mounted at the other, opposite end of the shaft, the vanes on the impellers are configured such that the gas flows along the axis of the turbine expander to the impellers, arranged on opposite ends of the rotor shaft elekrogeneratora have opposite directions. 2. The turboexpander power station according to claim 1, characterized in that it has a line for extracting natural gas from the high-pressure natural gas line connected to channels for supplying gas to the lubrication of the supports of the rotor of the generator, while the cavities of the exit of natural gas from the supports are communicated through an internal cavity an electric generator with an exhaust pipe connected to a natural gas supply line to a consumer. 3. The turboexpander power plant according to claim 1, characterized in that it has an annular cavity between the outer casing and the casing of the generator, connected on one side to a cavity for the exit of natural gas from the turboexpander, and on the other hand, with an exhaust pipe connected to the supply line natural gas to the consumer.